Some standard content:
Mechanical Industry Standard of the People's Republic of China
LOW-voltage contactors and AC motor starters in ships1 Subject content and scope of application
JB/T 2290-1993
Replaces JB2290-78
This standard specifies the general basic requirements for low-voltage contactors and AC motor starters in ships, including terms, characteristics, normal working and installation conditions, structure and performance requirements, test methods and inspection rules. This standard applies to low-voltage contactors and AC motor starters for ships or mobile and fixed offshore devices with AC 50Hz or 60Hz, voltage 1000V or DC 1200V and below in the main circuit. (hereinafter referred to as contactors and starters). This standard does not apply to the following contactors and starters: star-delta starters for special purposes and continuous operation in the starting position, rotor rheostat starters and auto-coupling pressure reducing starters; b. unbalanced (i.e. the resistance values of each phase are different) rotor rheostat starters; c. starters used not only for starting but also for speed regulation; d. liquid starters and "liquid-gas" starters; e. semiconductor contactors and starters using semiconductor contactors in the main circuit; ii. stator rheostat starters; iii. contactors and starters for special purposes. 2 Reference standards
GB3783
GB 14048.1
GB14048.2
GB 14048.4
GB14048.5
GB 2423. 4
GB 2423.16
GB 2423.17||tt| |GB 2900. 1
GB 2900.18
CB4025
GB4026
Basic requirements for marine low-voltage electrical appliances
General provisions for low-voltage switchgear and controlgear
Low-voltage switchgear and controlgearLow-voltage circuit breakersLow-voltage switchgear and controlgearLow-voltage electromechanical contactors and motor startersLow-voltage switchgear and controlgearControl circuitsElectrical appliances and switch elementsPart 1Electromechanical control circuitsElectrical appliancesBasic environmental testing procedures for electrical and electronic productsTest A: Low temperature test methodBasic environmental testing procedures for electrical and electronic productsTest B: High temperature test methodBasic environmental testing procedures for electrical and electronic productsTest Db: Alternating damp heat test methodBasic environmental testing procedures for electrical and electronic productsTest J: Mildew growth test methodBasic environmental testing procedures for electrical and electronic productsTest Ka: Salt spray test method Electrical terminology Basic terminology
Electrical terminology Low-voltage electrical appliances
General requirements for explosion-proof electrical apparatus for explosive atmospheres General requirements for explosion-proof electrical apparatus for explosive atmospheres Flameproof electrical apparatus "d" General requirements for explosion-proof electrical apparatus for explosive atmospheres Increased safety electrical apparatus e" General requirements for explosion-proof electrical apparatus for explosive atmospheres Intrinsically safe circuits and electrical apparatus "" General requirements for explosion-proof electrical apparatus for explosive atmospheres Positive pressure electrical apparatus "p" General requirements for explosion-proof electrical apparatus for explosive atmospheres Non-sparking electrical apparatus "n" Colors of indicator lights and buttons
General rules for identification of electrical wiring terminals and marking of wiring terminals with alphanumeric symbols Approved by the Ministry of Machinery Industry on October 8, 1993
1994-01-01 Implementation
GB4207
GB 4942. 2
GB6994
GB7094
ZJB K04 005
GB/T13384
JB3284
JB/T 2290—1993
Determination method of comparative tracking index and proof tracking index of solid insulating materials under humid conditionsDegree of protection of low-voltage electrical enclosures
Fire hazard test and platinum hot wire test method and guidelines for electrical and electronic productsGeneral provisions for marine electrical equipment
Vibration (sinusoidal) test method for marine electrical equipmentTilt and swing test method for marine electrical equipmentCable stuffing box
General technical conditions for packaging of motor products
Basic environmental conditions and test methods for transportation and storage of motor and electrical products3 Terms, symbols and codes
3.1 Terms
Except the terms specified in this standard, the definitions of other terms shall comply with the relevant provisions of GB2900.1, GB2900.18 and GB14048.1.
3.1.1 Terms related to contactors
Position of rest (of a contactor) The position of the movable part of the contactor when the electromagnet or compressed air device of the contactor is not in action. 3.1.2 Terms related to starters
3.1.2.1 Starter
A combination of all the switching devices required to start and stop the motor and appropriate overload protection devices. 3.1.2.2 Direct-on-line starter A starter that applies the circuit voltage directly to the motor terminals to start it at full voltage. 3.1.2.3 Reversing starter A starter that reverses the stator connection method when the motor is running. 3.1.2.4 Manual starter A starter in which the force to close the main contacts is completely generated manually. 3.1.2.5 Star-Delta Starter A starter that changes the connection of the stator winding of a three-phase squirrel cage asynchronous motor, connecting it in star at start and in delta during operation to reduce the starting current.
3.1.2.6 Under current relay A relay that operates when the current passing through it drops below the release current action value. 3.1.2.7 Closed transition (auto-coupling pressure reducing starter or star-delta starter) The closed transition circuit is designed so that when the starter is switched from star connection to delta connection or from one stage to another, the current of the motor is not interrupted during the transition process.
3.1.2.8 Open transition (auto-coupling pressure reducing starter or star-delta starter) The open transition circuit is designed so that when the starter is switched from star connection to delta connection or from one stage to another, the current of the motor is interrupted during the transition process.
3.J.2.9 Auto-transformer starter A starter that uses one or more taps from an auto-transformer to reduce the terminal voltage of an induction motor when starting, thereby reducing the starting current.
3.1.2.10E
Auto-transformerwwW.bzxz.Net
auto-transformer
A transformer with at least two windings and a common part. 3.1.2.11 Starting time (of an auto-transformer starter)2
The current-carrying time of the auto-transformer during starting. JB/T2290—1993
3. 1.2.12 Rheostatic starter A starter that uses one or more resistors to obtain the torque characteristics and (or) limit the current when the motor is started, including mechanical switching devices for cutting off the resistors.
The rheostatic starter usually consists of the following three basic components: a. Mechanical switching device for stator power supply (usually equipped with overload protection device); b.
A resistor connected to the rotor circuit; c.
A mechanical switching device for sequentially cutting off the resistor. C
These basic components can be provided in combination or separately and then connected at the place of use. 3.1.2.13 Rheostatic rotor starter A rheostatic starter that sequentially cuts off one or more resistors pre-connected in the rotor circuit of a wound rotor induction motor (hereinafter referred to as induction motor) during starting.
3. 1. 2. 14 Rheostatic stator starter A rheostatic starter that sequentially cuts off one or more resistors pre-connected in the stator circuit of a squirrel cage motor during starting. 3. 1.2.1s Starting time (of a rheostatic starter) The current-carrying time of the starting resistor or part of the starting resistor during starting. 3.1.2.16 Two-direction starter A starter that reverses the original wiring of the motor to reverse the motor only when the motor stops. 3.2 Symbols
Rated working voltage
Rated insulation voltage
Rated working current
Stator rated working voltage
Rotor rated working voltage
Stator rated insulation voltage
Rotor rated insulation voltage
Conventional thermal current
Conventional closed thermal current
Stator conventional thermal current
Rotor conventional thermal current
Stator rated working current
Rotor rated working current
Rated control power
Current instantaneous value
Period of a complete operating cycle
Trip time
Power-on time
Rated short-time withstand current
Rated control circuit voltage
Rated control power supply voltage
Breaking current
Making current
3.3 Code
Power supply voltage before making connection
Power supply voltage after breaking (recovery voltage)
Power factor
JB/T2290—1993
Comparative tracking index of short-circuit protection device (fuse or circuit breaker)
Time constant of test circuit
Alternating damp heat test
Over-oscillation coefficient
Oscillation frequency
Enclosure protection grade
See Table 1 for the commonly used usage category codes for contactors or starters. Table 1
Current type
Use category code
AC—1
AC—2
AC—3
AC—4
AC—5a
AC--5b
AC—6a
AC—6b
AC-—&a
AC—8b
DC—1
DC—5| |tt||DC—6
Non-inductive or low-inductive load, resistance furnace
Typical application examples
Starting of wound-rotor induction motors, disconnection of squirrel-cage induction motors, disconnection of squirrel-cage induction motors during operation, reverse braking and reverse operation, switching on and off of discharge lamps
On and off of incandescent lamps
On and off of transformers
On and off of capacitor banks
With manual reset Motor control in sealed refrigeration compressors with overload release Motor control in sealed refrigeration compressors with automatic reset overload release Non-inductive or low-inductive loads, resistance furnaces Starting, reverse braking or reverse operation, inching, and motor disconnection in dynamic state of shunt-excited motors Starting, reverse braking or reverse operation, inching, and motor disconnection in dynamic state of shunt-excited motors Switching on and off of incandescent lamps The types and models of contactors and starters in Article 5.2 of this standard can be used as the basis for classification 5 Characteristics Overview of characteristics The characteristics of contactors or starters are specified by the following items (when applicable): a. Type and type of electrical appliances (5.2), Rated values and limit values of main circuits (5.3); Category of use (5.4); Control circuits (5.5), Auxiliary circuits (5.6) JB/T 2290-1993
Types and characteristics of marine relays and trippers (5.7 (hereinafter referred to as relays and trippers); coordination with short-circuit protection devices (5.8), switching overvoltage (5.9),
Types and characteristics of automatic conversion devices and automatic acceleration control devices (5.10), types and characteristics of autotransformers for auto-coupling step-down starters (5.11); J
Types and characteristics of starting resistors for rotor variable resistance starters (5.12). k.
5.2 Types and types of contactors and starters 5.2.1 Types of contactors and starters
5.2.1.1 AC and DC contactors
5.2.1.2 AC motor starter
AC direct starter (including reversible starter).
a. Delta starter (the typical curve of the motor current, starting torque and driving mechanical torque is shown in Figure 1); b. Star-
auto coupling step-down starter (the typical curve of the motor current, starting torque and driving mechanical torque is shown in Figure 2) c.
d. Rotor variable resistance starter,
5.2.2 Number of poles
5.2.3 Type of current (AC or DC, AC including frequency) 5.2.4 Arc extinguishing medium
5.2.5 Operating conditions of electrical appliances
5.2.5.1 Mode of operation
a. Manual operation,
b. Power operation (electromagnet, motor, pneumatic, electro-pneumatic). 5.2.5.2 Mode of control
8. Automatic (operated by the main switch or controlled by a program controller); non-automatic (operated by hand or button); b.
c, semi-automatic (partially automatic, partly non-automatic control). 5.2.5.3 (Partial type) starter conversion mode The conversion of star-to-delta starter, rotor rheostat starter or auto-coupling pressure reducing starter can be automatic, non-automatic or semi-automatic (see Figures 3 and 4).
5.2.5.4 (Partial type) starter connection mode The starter with open circuit conversion and closed circuit conversion is shown in Figure 4. 5.3 Rated values and limit values of the main circuit
The rated values of the contactor or starter shall be expressed in accordance with the provisions of Articles 5.3 to 5.4, 5.8 and 5.9, and may be increased or decreased as required. 5.3.1 Rated voltage
The rated voltage of the contactor or starter is specified as follows: 5.3.1.1 Rated working voltage (U.)
Article 5.3.1.1 of GB3783 applies
5.3.1.1.1 Stator rated working voltage (Ues) The stator rated working voltage is expressed in line voltage. The stator rated working voltage of the rotor variable resistance starter together with the stator rated working current determines the purpose of the stator circuit (including its mechanical switching electrical appliances), and the breaking capacity, working system and starting characteristics are related to it. In any case, the maximum stator rated working voltage should not exceed the corresponding stator rated insulation voltage. 5.3.1.1.2 Rated rotor working voltage (U) 5
JB/T 2290--1993
The rated rotor working voltage of the rotor rheostatic starter, together with the rated rotor working current, determines the purpose of the rotor circuit (including its mechanical switchgear), and the switching capacity, duty and starting characteristics are related to it. The rated rotor working voltage is equal to the voltage measured between the slip rings when the rated working voltage is applied to the stator end of the motor, the motor stops and the rotor is open-circuited.
The rated rotor working voltage is only applied for a short time in the starting position, so the rated rotor working voltage is allowed to exceed the rated rotor insulation voltage by 100%.
When selecting and configuring equipment, it should be taken into account that the maximum voltages between different live parts in the starter rotor circuit (such as switchgear, rheostat, connectors, etc.) are different.
5.3.1.2 Rated insulation voltage (U.)
Article 5.3.1.2 of GB3783 applies.
5.3.1.2.1 Rated insulation voltage of stator (Uis) The rated insulation voltage of the stator of the rotor variable resistance starter is the voltage value related to the dielectric performance test and creepage distance of the electrical appliances and their components connected to the stator circuit. Unless otherwise specified, the rated insulation voltage of the stator is the maximum value of the rated working voltage of the starter stator. 5.3.1.2.2 Rated insulation voltage of rotor (U) The rated insulation voltage of the rotor of the rotor variable resistance starter is the voltage value related to the dielectric performance test and creepage distance of the electrical appliances and their components (connecting wires, resistors, and housing) connected to the rotor circuit. 5.3.1.3 Rated impulse withstand voltage (Uim) Article 5.3.1.3 of GB3783 applies.
5.3.1.4 Rated starting voltage of autotransformer step-down starter The rated starting voltage of the autotransformer step-down starter is the reduced voltage obtained from the tap of the autotransformer. The preferred value of the rated starting voltage is 80% and 65% of the rated working voltage, or 80% and 50%. 5.3.2 Current or power
Contactor or starter current is specified as follows: Note: The following current refers to the current value when the star-delta starter is connected in a delta connection, and to the current value in the full starting (running) state for the auto-coupling step-down starter and the rotor rheostat starter.
5.3.2.1 Conventional thermal current (Ith)
Article 5.3.2.1 of GB3783 applies.
5.3.2.2 Conventional closed thermal current (Ithe) Article 5.3.2.2 of GB3783 applies.
5.3.2.3 Conventional thermal current of stator (Iths) The conventional thermal current of the stator of the starter shall be consistent with the current I (Article 5.3.2.1) of the open type electrical appliance, or the current Ithes (5.3.2.2) of the closed type electrical appliance.
The conventional thermal current of the stator of the rotor variable resistance starter refers to the maximum current that the starter can carry under the eight-hour working system (see Article 5.3.4.1). Under this current, when the starter is tested according to Article 8.2.3.3, the temperature rise of each part shall not exceed the provisions of Article 7.2.2. 5.3.2.4 Conventional thermal current of rotor (Itx) The conventional thermal current of the rotor of the starter shall be consistent with the current Ithr (5.3.2.1) of the open type electrical appliance, or the current Ith (532.2) of the closed type electrical appliance.
The rotor agreed heating current of the rotor variable resistance starter refers to the maximum current that the parts of the starter that carry the rotor current can carry under the eight-hour working system (see Article 5.3.4.1) when the rotor is in the full starting position, that is, after the resistor is removed. Under this current, the starter is tested in accordance with Article 8.2.3.3, and its temperature rise should not exceed the provisions of Article 7.2.2. Note, ① For those components (switching devices, connecting wires, resistors) that actually have no current flowing through them at the full starting position, it should be verified that under the rated working system (Article 5.3.4) specified by the manufacturer, the integral value dt does not cause the temperature rise to exceed the provisions of Article 7.2.2. 6
JB/T 2290—1993
② When a resistor is installed in the starter, its influence on the temperature rise should be considered. 5.3.2.5 Rated operating current (Ie) or rated operating power The rated operating current of the contactor or starter is specified by the manufacturer taking into account the rated operating voltage (Article 5.3.1.1), the agreed heating current or agreed closed heating current, the rated current of the overload relay, the rated frequency (Article 5.3.3), the rated operating system (Article 5.3.4), the use category (Article 5.4) and the type of enclosure protection. For electrical appliances that directly switch on and off a single motor, the rated operating current can be replaced or supplemented by the maximum rated output power of the motor specified for the electrical appliance, taking into account the rated operating voltage. The manufacturer should provide the relationship between the motor power and the current. For starters, the rated operating current refers to the current of the starter in the full starting position. 5.3.2.6 Stator rated operating current (Ies) or stator rated operating power The stator rated operating current of the rotor rheostatic starter is specified by the manufacturer taking into account the rated current of the overload relay installed in the starter, the stator rated operating voltage (5.3.1.1.1), the stator agreed thermal current or agreed closed thermal current, the rated frequency (5.3.3), the rated operating system (5.3.4), the starting characteristics (5.3.5.4) and the type of enclosure protection. Under the condition of taking into account the stator rated operating voltage, the stator rated operating current can be replaced by the maximum rated output power of the motor that can be controlled by the stator circuit part of the starter. 5.3.2.7 Rated rotor operating current (Ier) The rated rotor operating current of a rotor rheostat starter is specified by the manufacturer taking into account the rated rotor operating voltage (Article 5.3.1.1.2), the rotor conventional thermal current or conventional closed thermal current, the rated frequency (Article 5.3.3), the rated duty (Article 5.3.4), the starting characteristics (Article 5.3.5.4) and the type of enclosure protection. The rated rotor operating current is equal to the current flowing through the rotor conductor when the rotor is short-circuited, the motor is running at full load, and the stator is supplied with the rated voltage and rated frequency.
When the rotor part of the rotor rheostat starter is rated separately, the rated rotor operating current can be supplemented by the maximum rated output power of the motor specified for the starter components (switching devices, connecting wires, relays, resistors) under the condition of taking into account the rated rotor operating voltage. In practice, this power varies mainly with the predetermined fatigue torque, so its starting characteristics should be considered. 5.3.2.8 Rated uninterrupted current ()
Article 5.3.2.4 of GB3783 applies.
5.3.3 Rated frequency
Article 5.3.3 of GB3783 applies.
5.3.4 Rated working system
Article 5.3.4 of GB3783 applies.
Under normal circumstances, the following rated working systems should be considered for contactors or starters. 5.3.4.1 Eight-hour working system
Article 5.3.4.1 of GB3783 applies, supplemented as follows: For star-delta starters, auto-coupling step-down starters or rotor rheostat starters, it means that when the main contacts of the starter remain closed in the full starting position, each main contact carries a stable current and lasts for a sufficient time to allow the starter to reach a thermal equilibrium state, but the power supply does not exceed eight hours.
5.3.4.2 Uninterrupted Duty
Article 5.3.4.2 of GB3783 is applicable, with the following additions: For star-delta starters, auto-coupling pressure-reducing starters or rotor rheostat starters, it refers to a duty system in which the main contacts of the starter remain closed in the full starting position, carrying a stable current and not disconnected for a duration of more than eight hours (weeks, months, years). 5.3.4.3 Intermittent Cycle Duty (abbreviated as intermittent duty system) Article 5.3.4.3 of GB3783 is applicable, with the following additions: For pressure-reducing starters, it refers to a duty system in which the time the main contacts of the starter's switch remain closed in the full starting position and the no-load time maintain a certain ratio, and both are very short, insufficient for the starter to reach thermal equilibrium. 7
The preferred level of intermittent duty is:
JB/T2290--1993
Contactor: The number of operating cycles per hour is: 1, 3, 12, 30, 120, 300, (600), 1200, 8
b. Starter: The number of operating cycles per hour is 1, 3, 12, 30. An operating cycle refers to a complete working cycle of one closing operation and one opening operation. For a starter, one operating cycle includes starting, running to full speed and disconnecting the motor power supply. Note: For starters under intermittent duty, the difference in thermal time constant between the overload relay and the motor may make the thermal relay unsuitable for overload protection. For the overload protection of equipment specified for intermittent duty, the manufacturer shall negotiate with the user. 5.3.4.4 Short-time duty
Article 5.3.4.4 of GB3783 applies.
5.3.4.3 Cyclic duty
Article 5.3.4.5 of GB3783 applies.
5.3.5 Normal load and overload characteristics
Article 5.3.5 of GB3783 applies, supplemented as follows: 5.3.5.1 Ability to withstand overload current of switching motors See 7.2.5.4 for specific requirements on the conditions that the contactor should meet. 5.3.5.2 The requirements for rated making capacity and rated breaking capacity corresponding to different use categories (Article 5.4) See 7.2.5.1. The rated making capacity and rated breaking capacity are valid only when the contactor or starter is operated according to the requirements of 7.2.1.1 and 7.2.1.2. 5.3.5.3 Agreed operating performance
The requirements for agreed operating performance corresponding to different use categories (Article 5.4) See 7.2.5.2. 5.3.5.4 Starting and stopping characteristics of the starter (see Figure 5) The typical use conditions of the starter are as follows:
. One direction of rotation, disconnecting the motor running under normal use conditions (AC-2 and AC-3 use categories), b. Two directions of rotation, but the second direction of operation can only be achieved after the starter has been disconnected and the motor has completely stopped (AC-2 and AC-3 use categories),
c. One direction of rotation or two directions of rotation as described in condition b, but with the possibility of infrequent jogging, direct starters are usually used in this use condition (AC-3 use category) d. One direction of rotation and frequent jogging, direct (full voltage) starters are usually used in this use condition (AC-4 use category); e. One or two directions of rotation, but with the possibility of infrequent reverse braking to stop the motor, reverse braking (if any) is performed with rotor resistance braking (reversing starter with brake), rotor resistance starters are usually used for this working condition (AC--2 use category),
f. Two directions of rotation, but when the motor rotates in one direction, in order to obtain the motor rotation in the other direction, the motor power supply under normal use conditions is disconnected and the motor power supply wiring is reversed to reverse (reverse braking and reversing), direct reversing starters are usually used for this working condition (AC-4 use category). 5.3.5.4.1 Starting characteristics of rotor variable resistance starter The current and voltage of the stator circuit and rotor circuit of the slip ring motor should be different. However, the changes in the current values of the stator and rotor circuits during the starting process are approximately proportional under normal working conditions. The rotor circuit has the following characteristic quantities:
Uer rotor rated working voltage,
Ier rotor rated working current,
Zr AC slip ring induction motor rotor characteristic impedance: Here Z, Uer/(3Ier)
The current value of the rotor circuit at the moment before shorting a resistor section; I
JB/T2290—1993
I2The current value of the rotor circuit at the moment after shorting a resistor section, I =- 0. 5( +I2)
TeThe rated working torque of the motor
t. Starting time (see 3.1.2.15); K Starting severity, i.e. I/Ier
Considering that different uses of rotor rheostat starters have different starting requirements, i.e., not only different starting stages and different I, and I, values are required, but also different I and I, values are required on each resistance segment, it is not necessary to list standard parameters, but the following factors should be considered:
For most applications, two to six starting stages are sufficient according to the requirements of load torque, inertia and starting severity. Each resistance segment should be considered to have sufficient heat resistance during the starting time of the drive mechanism, and the starting time is related to the load torque and load inertia.
5.3.5.4.2 Standard conditions for the making and breaking capacity of the starting characteristics of rotor rheostat starters. The conditions for the making and breaking capacity of the corresponding AC-2 use category given in Table 18 of this standard are standard conditions. This condition is applicable to high torque starting (see Figure 3 for the names of the relevant mechanical switch electrical appliances). The starter circuit should be designed to disconnect all rotor resistor switches before or approximately at the same time as the stator switch. Otherwise, the stator switch should comply with the requirements of the AC3 use category. 5.3.5.4.3 Starting characteristics of autotransformers Unless otherwise specified, autotransformers and especially autotransformers should be designed based on a starting time of no more than 15 seconds under all working conditions (see 5.3.4). For two starts in rapid succession, the starter and autotransformer are allowed to cool to the ambient air temperature before starting again. In addition, the number of operations per hour is assumed to be equal between the two starts. When the starting time needs to exceed 15 seconds, the manufacturer shall negotiate with the user. 5.3.6 Rated limiting short-circuit current
The rated limiting short-circuit current of a contactor or starter is the expected short-circuit current value that the device can well withstand within the operating time of the short-circuit protection device (SCPD) under the test conditions specified in the relevant product standards when protected by a designated short-circuit protection device (SCPD). It should be specified in the development that the AC rated limiting short-circuit current is expressed by the effective value of the AC component. The designated short-circuit protection device can be a component of the protected device or a separate electrical component. The specific situation should be specified by the manufacturer or product standard.
5.4 Use category
Article 5.4 of GB3783 is applicable, supplemented as follows: 5.4.1 Overview
The use category code and typical use of contactors or starters are shown in 3.3 of this standard. Other use categories should be negotiated by the manufacturer and the user. Each use category is characterized by the current, voltage, power factor, time constant and other data given in Table 18 and Table 21 and the test conditions specified in this standard.
For contactors and starters with specified use categories, since their rated contact and breaking capacity parameters are directly determined by the use categories listed in Table 18, these parameters do not need to be specified separately. The voltages of all use categories, except for the rotor rheostatic starter, which is the rated working voltage of the designator, refer to the rated working voltage of the contactor or starter.
All direct starters should belong to one or more of the following use categories: AC-3, AC-4, AC-8a, AC-8b. All star-delta and auto-coupling pressure reducing starters belong to the AC-3 use category. Rotor rheostatic starters belong to the AC-2 use category. 5.+.2 Provisions for selecting the use category based on test results a. If the contactor or starter has been tested for a use category or other parameter combination (such as the maximum working voltage and current), it can be selected for other use categories without testing as long as the following conditions are met. This condition is: the test current, voltage, power factor or time constant, number of operating cycles, closing and opening time parameters given in Table 18 and Table 21 of JB/T 2290-1993
and the test circuit of the selected use category are not more severe than the use category that the contactor or starter has been tested, and the current of the verification temperature rise test that has been carried out is not lower than the maximum value of the rated working current of the selected use category under the long-term working system. For example: when the contactor has been tested under the AC-4 use category, if the I. of AC-3 under the same rated working voltage is not higher than 1.2 times of the I. of AC-4 (but not more than I), the AC-3 use category can be selected for use. b. As long as the following conditions are met, the contactors of the DC-3 and DC-5 use categories are considered to have the ability to disconnect and connect non-test loads (not the test parameters they have been tested for). These conditions are: the current and voltage do not exceed the I. and U. values of the specified test, and the energy stored in the actual load is equal to or less than the energy J. stored in the contactor's tested load. The energy values stored in the test circuit are as follows: for use category DC-3, the stored energy J. is 0.00525U.Ie, and for use category DC-5, the stored energy J is 0.0315U.Ic. The coefficients 0.00525 and 0.0315 are obtained from the following formula: J. = 0. 5LI2
The above formula can be transformed into: J = 2.1×(L/R)UI. The time constant (L/R) in the formula is replaced by 2.5×10-\S(DC-3) and 15×10~3S(DC—5) in Table 18, and U = 1.05U. , I = 4Ie.
5.SControl circuit
Article 5.5 of GB3783 applies.
5.6Auxiliary circuit
Article 5.6 of GB3783 applies.
5.7Types and characteristics of relays and releases (overload relays) Note: In the following parts of this standard, "overload relay" means "overload relay or overload release". 5.7.1 Summary of characteristics
The characteristics of relays and trip units are specified as follows (if applicable): a. Type of relay or trip unit (clause 5.7.2); b. Characteristic quantity (clause 5.7.3); c. Current setting value and mark of overload relay (clause 5.7.4); d. Time-current characteristic of overload relay (clause 5.7.5), influence of ambient air temperature (clause 5.7.6). e.
5.7.2 Types of relays and releases
Releasers with shunt coils (shunt releases) 5. 7. 2. 1
5. 7. 2. 2
Relays or releases with undervoltage and undercurrent actions 5.7.2.3 Overload delay relays
The delay types are:
Actually unrelated to the original load (such as electromagnetic delay overload relays), a.
b. Related to the original load (such as thermal overload relays), c. Related to the original load (such as thermal overload relays) and with phase failure protection. 5.7.2.4 Instantaneous overcurrent relay or release (if applicable) 5.7.2.5 Other relays or releases (such as control relays for the combination of phase-off relays and starter thermal protectors) Note: The types mentioned in 5.7.2.4 and 5.7.2.5 above shall be negotiated between the manufacturer and the user as required. 5.7.3 Characteristic quantities
5.7.3.1 Relays or releases with shunt coil releases and undervoltage (undercurrent) action. Rated voltage (current):
b. Rated frequency,
c. Action voltage (current).
5.7.3.2 Overload relay
Current setting value or mark;
JB/T 2290—1993
Rated frequency (such as current transformer or overload relay), time-to-current characteristics (or current characteristic range); c.
Maximum tripping time when the tripping time exceeds 30s under the conditions specified in column D of table 10 of clause 7.2.1.5, in $
eNumber of poles,
f. Type of relay: thermal, electromagnetic or solid-state. Table 2
Trip level
Trip time T under the conditions specified in column D of table 10 of clause 7.2.1.5, 828282Uer/（3Ier）
The current value of the rotor circuit immediately before a resistor section is shorted; I
JB/T2290—1993
I2The current value of the rotor circuit immediately after a resistor section is shorted, I =- 0. 5( +I2)
TeThe rated working torque of the motor
t. Starting time (see 3.1.2.15); KStarting severity, that is, I/Ier
Considering that different uses of rotor variable resistance starters have different starting requirements, that is, different starting stages and different I, and I, values are required, and different I and I, values are required on each resistor section, it is not necessary to list standard parameters, but the following factors should be considered:
For most applications, two to six starting stages are sufficient according to the requirements of load torque, inertia and starting severity. Each resistor section should be considered to have sufficient heat resistance during the starting time of the drive mechanism. The starting time is related to the load torque and load inertia.
5.3.5.4.2 Standard conditions for the making and breaking capacity of the rotor variable resistance starter starting characteristics. The conditions for the making and breaking capacity of the corresponding AC-2 use category given in Table 18 of this standard are standard conditions. This condition is applicable to high torque starting (see Figure 3 for the names of the relevant mechanical switching devices). The starter circuit should be designed to disconnect the switching devices of all rotor resistors before or approximately at the same time as the stator switching devices are disconnected. Otherwise, the stator switching devices should meet the requirements of the AC3 use category. 5.3.5.4.3 Starting characteristics of autotransformers Unless otherwise specified, autotransformers, especially autotransformers, should be designed based on a starting time of no more than 15s under all working conditions (see Article 5.3.4). For two starts in quick succession, the starter and autotransformer are allowed to cool to the ambient air temperature before starting again. In addition, the number of operations per hour assumes that the period between the two starts is equal. When the starting time needs to exceed 15s, the manufacturer and the user shall negotiate. 5.3.6 Rated limiting short-circuit current
The rated limiting short-circuit current of the contactor or starter is the expected short-circuit current value that the electrical appliance protected by the specified short-circuit protection device (SCPD) can well withstand within the action time of the short-circuit protection device under the test conditions specified in the relevant product standards. It should be specified in the development that the AC rated limiting short-circuit current is expressed in terms of the effective value of the AC component. The specified short-circuit protection device can be a component of the protected electrical appliance or a separate electrical component. The specific situation should be specified by the manufacturer or product standards.
5.4 Use category
Article 5.4 of GB3783 is applicable, supplemented as follows: 5.4.1 Overview
The use category code of contactors or starters and their typical uses are shown in 3.3 of this standard. Other use categories should be negotiated by the manufacturer and the user. Each use category is characterized by the current, voltage, power factor, time constant and other data given in Table 18 and Table 21 and the test conditions specified in this standard.
For contactors and starters with specified use categories, since their rated contact and breaking capacity parameters are directly determined by the use categories listed in Table 18, it is not necessary to specify these parameters separately. The voltages of all use categories, except for the rated working voltage of the rotor rheostat starter, refer to the rated working voltage of the contactor or starter.
All direct starters should belong to one or more of the following use categories: AC-3, AC-4, AC-8a, AC-8b. All star-delta and auto-coupling starters belong to the AC-3 use category. Rotor variable resistance starters belong to the AC-2 use category. 5.+.2 Provisions for selecting the use category based on test results a. If the contactor or starter has been tested for a use category or other parameter combinations (such as the maximum working voltage and current), it can be selected for other use categories without testing as long as the following conditions are met. This condition is: the test current, voltage, power factor or time constant, number of operating cycles, closing and opening time parameters given in Table 18 and Table 21 of JB/T 2290-1993
and the test circuit of the selected use category are not more severe than the use category that the contactor or starter has been tested for, and the current of the verification temperature rise test that has been conducted is not lower than the maximum value of the rated working current of the selected use category under the long-term working system. For example: when the contactor has been tested under the AC-4 use category, such as the I of AC-3 under the same rated working voltage. Not higher than the I of AC-4. b. If the current and voltage do not exceed the I. and U. values of the specified test, and the energy stored in the actual load is equal to or less than the energy J. stored in the contactor's tested load. The energy values stored in the test circuit are as follows: for use category DC-3, the stored energy J. is 0.00525U.Ie, and for use category DC-5, the stored energy J. is 0.0315U.Ic. The coefficients 0.00525 and 0.0315 are obtained from the following formula: J. = 0.5LI2
The above formula can be transformed into: J = 2.1×(L/R)UI. The time constant (L/R) in the formula is replaced by 2.5×10-\S(DC-3) and 15×10~3S(DC—5) in Table 18, and U=1.05U. , I=4Ie.
5.S Control circuit
Article 5.5 of GB3783 applies.
5.6 Auxiliary circuit
Article 5.6 of GB3783 applies.
5.7 Type and characteristics of relays and releases (overload relays) Note: In the following parts of this standard, "overload relay" means "overload relay or overload release". 5.7.1 Summary of characteristics
The characteristics of relays and releases are specified as follows (if applicable): Cover. Type of relay or release (Article 5.7.2); b. Characteristic quantity (Article 5.7.3)
Current setting value and mark of overload relay (Article 5.7.4) c.
d. Time-current characteristic of overload relay (Article 5.7.5), influence of ambient air temperature (Article 5.7.6). e.
5.7.2 Types of relays and releasers
Releaser with shunt coil (shunt release) 5. 7. 2. 1
5. 7. 2. 2
Relay or release with undervoltage and undercurrent action 5.7.2.3 Overload delay relay
The delay type is:
Actually unrelated to the original load (such as electromagnetic delay overload relay), a.
b. Related to the original load (such as thermal overload relay), c. Related to the original load (such as thermal overload relay) and has phase failure protection. 5.7.2.4 Instantaneous overcurrent relay or release (if applicable) 5.7.2.5 Other relays or releases (such as control relays for the combination of phase-off relays and starter thermal protectors) Note: The types mentioned in 5.7.2.4 and 5.7.2.5 above shall be negotiated between the manufacturer and the user as required. 5.7.3 Characteristic quantities
5.7.3.1 Relays or releases with shunt coil releases and undervoltage (undercurrent) action. Rated voltage (current):
b. Rated frequency,
c. Action voltage (current).
5.7.3.2 Overload relay
Current setting value or mark;
JB/T 2290—1993
Rated frequency (such as current transformer or overload relay), time-to-current characteristics (or current characteristic range); c.
Maximum tripping time when the tripping time exceeds 30s under the conditions specified in column D of table 10 of clause 7.2.1.5, in $
eNumber of poles,
f. Type of relay: thermal, electromagnetic or solid-state. Table 2
Trip level
Trip time T under the conditions specified in column D of table 10 of clause 7.2.1.5, 82Uer/（3Ier）
The current value of the rotor circuit immediately before a resistor section is shorted; I
JB/T2290—1993
I2The current value of the rotor circuit immediately after a resistor section is shorted, I =- 0. 5( +I2)
TeThe rated working torque of the motor
t. Starting time (see 3.1.2.15); KStarting severity, that is, I/Ier
Considering that different uses of rotor variable resistance starters have different starting requirements, that is, different starting stages and different I, and I, values are required, and different I and I, values are required on each resistor section, it is not necessary to list standard parameters, but the following factors should be considered:
For most applications, two to six starting stages are sufficient according to the requirements of load torque, inertia and starting severity. Each resistor section should be considered to have sufficient heat resistance during the starting time of the drive mechanism. The starting time is related to the load torque and load inertia.
5.3.5.4.2 Standard conditions for the making and breaking capacity of the rotor variable resistance starter starting characteristics. The conditions for the making and breaking capacity of the corresponding AC-2 use category given in Table 18 of this standard are standard conditions. This condition is applicable to high torque starting (see Figure 3 for the names of the relevant mechanical switching devices). The starter circuit should be designed to disconnect the switching devices of all rotor resistors before or approximately at the same time as the stator switching devices are disconnected. Otherwise, the stator switching devices should meet the requirements of the AC3 use category. 5.3.5.4.3 Starting characteristics of autotransformers Unless otherwise specified, autotransformers, especially autotransformers, should be designed based on a starting time of no more than 15s under all working conditions (see Article 5.3.4). For two starts in quick succession, the starter and autotransformer are allowed to cool to the ambient air temperature before starting again. In addition, the number of operations per hour assumes that the period between the two starts is equal. When the starting time needs to exceed 15s, the manufacturer and the user shall negotiate. 5.3.6 Rated limiting short-circuit current
The rated limiting short-circuit current of the contactor or starter is the expected short-circuit current value that the electrical appliance protected by the specified short-circuit protection device (SCPD) can well withstand within the action time of the short-circuit protection device under the test conditions specified in the relevant product standards. It should be specified in the development that the AC rated limiting short-circuit current is expressed in terms of the effective value of the AC component. The specified short-circuit protection device can be a component of the protected electrical appliance or a separate electrical component. The specific situation should be specified by the manufacturer or product standards.
5.4 Use category
Article 5.4 of GB3783 is applicable, supplemented as follows: 5.4.1 Overview
The use category code of contactors or starters and their typical uses are shown in 3.3 of this standard. Other use categories should be negotiated by the manufacturer and the user. Each use category is characterized by the current, voltage, power factor, time constant and other data given in Table 18 and Table 21 and the test conditions specified in this standard.
For contactors and starters with specified use categories, since their rated contact and breaking capacity parameters are directly determined by the use categories listed in Table 18, it is not necessary to specify these parameters separately. The voltages of all use categories, except for the rated working voltage of the rotor rheostat starter, refer to the rated working voltage of the contactor or starter.
All direct starters should belong to one or more of the following use categories: AC-3, AC-4, AC-8a, AC-8b. All star-delta and auto-coupling starters belong to the AC-3 use category. Rotor variable resistance starters belong to the AC-2 use category. 5.+.2 Provisions for selecting the use category based on test results a. If the contactor or starter has been tested for a use category or other parameter combinations (such as the maximum working voltage and current), it can be selected for other use categories without testing as long as the following conditions are met. This condition is: the test current, voltage, power factor or time constant, number of operating cycles, closing and opening time parameters given in Table 18 and Table 21 of JB/T 2290-1993
and the test circuit of the selected use category are not more severe than the use category that the contactor or starter has been tested for, and the current of the verification temperature rise test that has been conducted is not lower than the maximum value of the rated working current of the selected use category under the long-term working system. For example: when the contactor has been tested under the AC-4 use category, such as the I of AC-3 under the same rated working voltage. Not higher than the I of AC-4. b. If the current and voltage do not exceed the I. and U. values of the specified test, and the energy stored in the actual load is equal to or less than the energy J. stored in the contactor's tested load. The energy values stored in the test circuit are as follows: for use category DC-3, the stored energy J. is 0.00525U.Ie, and for use category DC-5, the stored energy J. is 0.0315U.Ic. The coefficients 0.00525 and 0.0315 are obtained from the following formula: J. = 0.5LI2
The above formula can be transformed into: J = 2.1×(L/R)UI. The time constant (L/R) in the formula is replaced by 2.5×10-\S(DC-3) and 15×10~3S(DC—5) in Table 18, and U=1.05U. , I=4Ie.
5.S Control circuit
Article 5.5 of GB3783 applies.
5.6 Auxiliary circuit
Article 5.6 of GB3783 applies.
5.7 Type and characteristics of relays and releases (overload relays) Note: In the following parts of this standard, "overload relay" means "overload relay or overload release". 5.7.1 Summary of characteristics
The characteristics of relays and releases are specified as follows (if applicable): Cover. Type of relay or release (Article 5.7.2); b. Characteristic quantity (Article 5.7.3)
Current setting value and mark of overload relay (Article 5.7.4) c.
d. Time-current characteristic of overload relay (Article 5.7.5), influence of ambient air temperature (Article 5.7.6). e.
5.7.2 Types of relays and releasers
Releaser with shunt coil (shunt release) 5. 7. 2. 1
5. 7. 2. 2
Relay or release with undervoltage and undercurrent action 5.7.2.3 Overload delay relay
The delay type is:
Actually unrelated to the original load (such as electromagnetic delay overload relay), a.
b. Related to the original load (such as thermal overload relay), c. Related to the original load (such as thermal overload relay) and has phase failure protection. 5.7.2.4 Instantaneous overcurrent relay or release (if applicable) 5.7.2.5 Other relays or releases (such as control relays for the combination of phase-off relays and starter thermal protectors) Note: The types mentioned in 5.7.2.4 and 5.7.2.5 above shall be negotiated between the manufacturer and the user as required. 5.7.3 Characteristic quantities
5.7.3.1 Relays or releases with shunt coil releases and undervoltage (undercurrent) action. Rated voltage (current):
b. Rated frequency,
c. Action voltage (current).
5.7.3.2 Overload relay
Current setting value or mark;
JB/T 2290—1993
Rated frequency (such as current transformer or overload relay), time-to-current characteristics (or current characteristic range); c.
Maximum tripping time when the tripping time exceeds 30s under the conditions specified in column D of table 10 of clause 7.2.1.5, in $
eNumber of poles,
f. Type of relay: thermal, electromagnetic or solid-state. Table 2
Trip level
Trip time T under the conditions specified in column D of table 10 of clause 7.2.1.5, 8215); K Starting severity, that is, I/Ier
Considering that different uses of rotor rheostatic starters have different starting requirements, that is, not only different starting stages and different I, and I, values are required, but also different I and I, values are required on each resistance segment. Therefore, it is not necessary to list standard parameters, but the following factors should be considered:
For most applications, two to six starting stages are sufficient according to the requirements of load torque, inertia and starting severity. Each resistance segment should be considered to have sufficient heat resistance during the starting time of the drive mechanism. The starting time is related to the load torque and load inertia.
5.3.5.4.2 Standard conditions for the making and breaking capacity of the starting characteristics of rotor rheostatic starters. The conditions for the making and breaking capacity of the corresponding AC-2 use category given in Table 18 of this standard are standard conditions. This condition is applicable to high torque starting (see Figure 3 for the names of the relevant mechanical switching electrical appliances). The starter circuit should be designed to disconnect all rotor resistor switches before or approximately at the same time as the stator switch. Otherwise, the stator switch should comply with the requirements of the AC3 use category. 5.3.5.4.3 Starting characteristics of autotransformers Unless otherwise specified, autotransformers and especially autotransformers should be designed based on a starting time of no more than 15 seconds under all working conditions (see 5.3.4). For two starts in rapid succession, the starter and autotransformer are allowed to cool to the ambient air temperature before starting again. In addition, the number of operations per hour is assumed to be equal between the two starts. When the starting time needs to exceed 15 seconds, the manufacturer shall negotiate with the user. 5.3.6 Rated limiting short-circuit current
The rated limiting short-circuit current of a contactor or starter is the expected short-circuit current value that the device can well withstand within the operating time of the short-circuit protection device (SCPD) under the test conditions specified in the relevant product standards when protected by a designated short-circuit protection device (SCPD). It should be specified in the development that the AC rated limiting short-circuit current is expressed by the effective value of the AC component. The designated short-circuit protection device can be a component of the protected device or a separate electrical component. The specific situation should be specified by the manufacturer or product standard.
5.4 Use category
Article 5.4 of GB3783 is applicable, supplemented as follows: 5.4.1 Overview
The use category code and typical use of contactors or starters are shown in 3.3 of this standard. Other use categories should be negotiated by the manufacturer and the user. Each use category is characterized by the current, voltage, power factor, time constant and other data given in Table 18 and Table 21 and the test conditions specified in this standard.
For contactors and starters with specified use categories, since their rated contact and breaking capacity parameters are directly determined by the use categories listed in Table 18, these parameters do not need to be specified separately. The voltages of all use categories, except for the rotor rheostatic starter, which is the rated working voltage of the designator, refer to the rated working voltage of the contactor or starter.
All direct starters should belong to one or more of the following use categories: AC-3, AC-4, AC-8a, AC-8b. All star-delta and auto-coupling pressure reducing starters belong to the AC-3 use category. Rotor rheostatic starters belong to the AC-2 use category. 5.+.2 Provisions for selecting the use category based on test results a. If the contactor or starter has been tested for a use category or other parameter combination (such as the maximum working voltage and current), it can be selected for other use categories without testing as long as the following conditions are met. This condition is: the test current, voltage, power factor or time constant, number of operating cycles, closing and opening time parameters given in Table 18 and Table 21 of JB/T 2290-1993
and the test circuit of the selected use category are not more severe than the use category that the contactor or starter has been tested, and the current of the verification temperature rise test that has been carried out is not lower than the maximum value of the rated working current of the selected use category under the long-term working system. For example: when the contactor has been tested under the AC-4 use category, if the I. of AC-3 under the same rated working voltage is not higher than 1.2 times of the I. of AC-4 (but not more than I), the AC-3 use category can be selected for use. b. As long as the following conditions are met, the contactors of the DC-3 and DC-5 use categories are considered to have the ability to disconnect and connect non-test loads (not the test parameters they have been tested for). These conditions are: the current and voltage do not exceed the I. and U. values of the specified test, and the energy stored in the actual load is equal to or less than the energy J. stored in the contactor's tested load. The energy values stored in the test circuit are as follows: for use category DC-3, the stored energy J. is 0.00525U.Ie, and for use category DC-5, the stored energy J is 0.0315U.Ic. The coefficients 0.00525 and 0.0315 are obtained from the following formula: J. = 0. 5LI2
The above formula can be transformed into: J = 2.1×(L/R)UI. The time constant (L/R) in the formula is replaced by 2.5×10-\S(DC-3) and 15×10~3S(DC—5) in Table 18, and U = 1.05U. , I = 4Ie.
5.SControl circuit
Article 5.5 of GB3783 applies.
5.6Auxiliary circuit
Article 5.6 of GB3783 applies.
5.7Types and characteristics of relays and releases (overload relays) Note: In the following parts of this standard, "overload relay" means "overload relay or overload release". 5.7.1 Summary of characteristics
The characteristics of relays and trip units are specified as follows (if applicable): a. Type of relay or trip unit (clause 5.7.2); b. Characteristic quantity (clause 5.7.3); c. Current setting value and mark of overload relay (clause 5.7.4); d. Time-current characteristic of overload relay (clause 5.7.5), influence of ambient air temperature (clause 5.7.6). e.
5.7.2 Types of relays and releases
Releasers with shunt coils (shunt releases) 5. 7. 2. 1
5. 7. 2. 2
Relays or releases with undervoltage and undercurrent actions 5.7.2.3 Overload delay relays
The delay types are:
Actually unrelated to the original load (such as electromagnetic delay overload relays), a.
b. Related to the original load (such as thermal overload relays), c. Related to the original load (such as thermal overload relays) and with phase failure protection. 5.7.2.4 Instantaneous overcurrent relay or release (if applicable) 5.7.2.5 Other relays or releases (such as control relays for the combination of phase-off relays and starter thermal protectors) Note: The types mentioned in 5.7.2.4 and 5.7.2.5 above shall be negotiated between the manufacturer and the user as required. 5.7.3 Characteristic quantities
5.7.3.1 Relays or releases with shunt coil releases and undervoltage (undercurrent) action. Rated voltage (current):
b. Rated frequency,
c. Action voltage (current).
5.7.3.2 Overload relay
Current setting value or mark;
JB/T 2290—1993
Rated frequency (such as current transformer or overload relay), time-to-current characteristics (or current characteristic range); c.
Maximum tripping time when the tripping time exceeds 30s under the conditions specified in column D of table 10 of clause 7.2.1.5, in $
eNumber of poles,
f. Type of relay: thermal, electromagnetic or solid-state. Table 2
Trip level
Trip time T under the conditions specified in column D of table 10 of clause 7.2.1.5, 8215); K Starting severity, that is, I/Ier
Considering that different uses of rotor rheostatic starters have different starting requirements, that is, not only different starting stages and different I, and I, values are required, but also different I and I, values are required on each resistance segment. Therefore, it is not necessary to list standard parameters, but the following factors should be considered:
For most applications, two to six starting stages are sufficient according to the requirements of load torque, inertia and starting severity. Each resistance segment should be considered to have sufficient heat resistance during the starting time of the drive mechanism. The starting time is related to the load torque and load inertia.
5.3.5.4.2 Standard conditions for the making and breaking capacity of the starting characteristics of rotor rheostatic starters. The conditions for the making and breaking capacity of the corresponding AC-2 use category given in Table 18 of this standard are standard conditions. This condition is applicable to high torque starting (see Figure 3 for the names of the relevant mechanical switching electrical appliances). The starter circuit should be designed to disconnect all rotor resistor switches before or approximately at the same time as the stator switch. Otherwise, the stator switch should comply with the requirements of the AC3 use category. 5.3.5.4.3 Starting characteristics of autotransformers Unless otherwise specified, autotransformers and especially autotransformers should be designed based on a starting time of no more than 15 seconds under all working conditions (see 5.3.4). For two starts in rapid succession, the starter and autotransformer are allowed to cool to the ambient air temperature before starting again. In addition, the number of operations per hour is assumed to be equal between the two starts. When the starting time needs to exceed 15 seconds, the manufacturer shall negotiate with the user. 5.3.6 Rated limiting short-circuit current
The rated limiting short-circuit current of a contactor or starter is the expected short-circuit current value that the device can well withstand within the operating time of the short-circuit protection device (SCPD) under the test conditions specified in the relevant product standards when protected by a designated short-circuit protection device (SCPD). It should be specified in the development that the AC rated limiting short-circuit current is expressed by the effective value of the AC component. The designated short-circuit protection device can be a component of the protected device or a separate electrical component. The specific situation should be specified by the manufacturer or product standard.
5.4 Use category
Article 5.4 of GB3783 is applicable, supplemented as follows: 5.4.1 Overview
The use category code and typical use of contactors or starters are shown in 3.3 of this standard. Other use categories should be negotiated by the manufacturer and the user. Each use category is characterized by the current, voltage, power factor, time constant and other data given in Table 18 and Table 21 and the test conditions specified in this standard.
For contactors and starters with specified use categories, since their rated contact and breaking capacity parameters are directly determined by the use categories listed in Table 18, these parameters do not need to be specified separately. The voltages of all use categories, except for the rotor rheostatic starter, which is the rated working voltage of the designator, refer to the rated working voltage of the contactor or starter.
All direct starters should belong to one or more of the following use categories: AC-3, AC-4, AC-8a, AC-8b. All star-delta and auto-coupling pressure reducing starters belong to the AC-3 use category. Rotor rheostatic starters belong to the AC-2 use category. 5.+.2 Provisions for selecting the use category based on test results a. If the contactor or starter has been tested for a use category or other parameter combination (such as the maximum working voltage and current), it can be selected for other use categories without testing as long as the following conditions are met. This condition is: the test current, voltage, power factor or time constant, number of operating cycles, closing and opening time parameters given in Table 18 and Table 21 of JB/T 2290-1993
and the test circuit of the selected use category are not more severe than the use category that the contactor or starter has been tested, and the current of the verification temperature rise test that has been carried out is not lower than the maximum value of the rated working current of the selected use
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