This standard specifies the requirements for built-in thermal protectors for rotating electrical machines. This standard applies to thermal protectors used in rotating electrical machines with rated voltages of 660V and below and rated power of 11kW and below that comply with the requirements of GB755. This standard also applies to motors with other ratings specified in a special agreement between the motor manufacturer and the user. This standard does not apply to thermal detectors that cut off the control circuit of the motor switching device when the thermal protection system is activated. For household appliances or electrical equipment used in explosive environments, corresponding additional requirements may be added according to special use needs. GB 13232-1991 General rules for built-in thermal protectors of rotating electrical machines GB13232-1991 Standard download and decompression password: www.bzxz.net

National Standard of the People's Republic of China
Built-in thermal protection for rotating electrical machinesGeneral rules for thermal protectorsGB13232-91||tt| |This standard is equivalent to the international standard IEC34-11-3 (1984) "General Principles of Thermal Protectors for Thermal Protection Systems". 1Subject content and scope of application
This standard specifies the requirements for built-in thermal protectors for rotating electrical machines. This standard applies to thermal protectors used in rotating electrical machines with rated voltages of 660V and below and rated power of 11kW and below that comply with the requirements of GB755.
This standard also applies to motors with other ratings specified in a special agreement between the motor manufacturer and the user. This standard does not apply to thermal detectors that cut off the control circuit of the motor switching device when the thermal protection system is activated. For household appliances or electrical equipment used in explosive environments, corresponding additional requirements may be added according to special use needs. 2 Reference Standards
GB755 Basic Technical Requirements for Rotating Electric Machines
GB/T13002 Rotating Electric Machines Built-in Thermal Protection Protection Rules for Rotating Electrical Machines JB24551
Low Voltage Contactors
3 Terms
Terms specific to this standard are as follows:
3.1 Automatic reset thermal protector
A device that operates to cut off power to the motor in response to overheating and/or overloading of the motor windings. When it cools to the reset temperature, the motor power can be reconnected without external push.
3.2 Manual Reset Thermal ProtectorbzxZ.net
A device that operates to cut off power to the motor in response to overheating and/or overloading of the motor windings. When it cools down to operating temperature, the motor power cannot be reconnected without external push. 3.3 Rated disconnection temperature
The temperature at which the thermal protector disconnects the circuit when it does not carry any current and the temperature rise rate is slow. 3.4 Reset temperature
The temperature drops slowly and the thermal protector reconnects the circuit or the temperature when the circuit can be connected. 3.5 Free trip
The thermal protector disconnection circuit has nothing to do with the operation or position of the reset handle or button, which is free trip. 3.6 Rated tripping current
State Bureau of Technical Supervision approved on 1992-08-01 for implementation on 1992-08-01
GB13232--91
When the ambient temperature is 25℃, in a standard Calculate the current that causes the thermal protector to trip within a certain period of time. 3.7 Critical tripping current
The maximum continuous current that the thermal protector can carry without opening the circuit under a specific ambient temperature. 4 Thermal protector design and structural principles
4.1 Exposed parts
After the thermal protector is installed into the motor according to conventional use, except for the reset handle or button, the remaining operating parts should not be exposed or insulated. Live parts should also not be exposed. The protection level of the thermal protector should be no less than IP2X. 4.2 Thermal protector type
The thermal protector has two types: automatic reset and manual reset. 4.3 Structure
The structure of the thermal protector should ensure that its thermal characteristics are difficult to change. Note: Use sealing or locking nuts to meet requirements. . 4.4 Electrical connection
Electrical connection shall comply with the provisions of Article 6.2.2 of GB/T13002. 5 Action characteristics
The thermal protector operates in response to the temperature and current of the motor. Generally, it does not take the heating current and operating current as the rating. The current and temperature characteristics of the thermal protector are specified based on the specific conditions when the thermal protector is installed in the motor and withstands slow-changing and fast-changing thermal overloads in Article 5 of GB/T13002.
5.1 Rated disconnection temperature
Thermal protector manufacturer should specify the rated disconnection temperature of the product. If there is no other agreement between the motor manufacturer and the thermal protector manufacturer, the tolerance of the nominal value of the rated disconnection temperature is ±6°C. 5.2 Reset temperature
If required when ordering, the thermal protector manufacturer should specify the reset temperature of the product and its tolerance. If there is no other agreement between the motor manufacturer and the thermal protector manufacturer, the tolerance of the nominal value of the reset temperature of the automatic reset thermal protector is ±15°C.
5.3 Rated voltage
The thermal protector manufacturer should specify the rated voltage of the thermal protector, and its value should not be lower than the rated voltage of the protected motor. 5.4 Current/temperature characteristics of the thermal protector
5.4.1 Rated tripping current
The thermal protector manufacturer should specify the rated tripping current, nominal time and nominal time of the thermal protector Tolerance. Note: For commonly used thermal protector series, the manufacturer should usually provide the rated tripping current and nominal tripping time of the thermal protector under the specified ambient temperature in the form of a chart or curve.
5.4.2 Critical tripping current
The thermal protector manufacturer should provide the motor manufacturer with the characteristic data of the thermal protector's critical tripping current versus ambient temperature in the form of a data table or curve.
5.5 Trip characteristics
The manual reset thermal protector should be able to trip freely. When the temperature is higher than -5℃, the manual reset thermal protector should not be able to automatically close the circuit. Note: In low-temperature applications, if there is another agreement between the thermal protector manufacturer and the motor manufacturer, the automatic reset temperature limit of the manual reset thermal protector can be lower.
5.6 lifespan
5.6.1 Manual reset thermal protector
GB13232-91
The manual reset thermal protector installed in the motor, when the motor rotor is locked In addition to 10 action cycles according to GB/T13002 Article 7.3.2, it should also be able to withstand 50 action cycles without damage. 5.6.2 Automatic reset thermal protector
The automatic reset thermal protector installed in the motor, when the motor rotor is blocked, in addition to the 72h test specified in GB/T13002 Article 7.4, it should also withstand a period of 15d Continuous cyclic action without damage. The total test time is 18 days, and the action cycle is no less than 2000 times. The purpose of the added 15d test is to evaluate the life of the thermal protector installed in the motor. During this test, the thermal protector is likely to deviate from its original characteristics, and the temperature of the motor may also exceed the value specified in Article 7.4 of GB/T13002. The life of the thermal protector should be evaluated based on the state of the motor at the end of the 18-day test. At this time, the thermal protector should still be operating, and the motor has not suffered any dangerous damage specified in Article 9.7.4. If the motor is dangerously damaged, the thermal protector should be considered unsuitable. Note: ① In order to assist the motor manufacturer in selecting a suitable thermal protector, the thermal protector manufacturer should not only provide the following data, but also provide a life description of this type of thermal protector:
expected cycle time; || tt||Expected current;
Power factor;
Rated disconnection temperature:
Reset temperature.
Some electrical equipment is equipped with a built-in timer or a manual momentary switch, which prevents the motor from being continuously energized, thus limiting the number of action cycles. This limitation should be stipulated by the corresponding standards of this type of equipment. 5.7 Ultimate short-circuit performance of the thermal protector
5.7.1 The thermal protector installed at the incoming end of the motor winding The thermal protector installed in the motor should be able to withstand the short-circuit current specified in Table 1 without burning. Table 1
Motor rated power P
kw
≤0.4
>0.4~0.8
>0.8~2.2
>2.2~ 5.6
>5.6
0.8
>0.8
Thermal protector rated voltage
V
≤250
> 250 |2The expected current of the thermal protector installed at the neutral point of the three-phase motor "
A
200
1000
2000
3500||tt| |5000
1000
5000
Star-connected three-phase motor, when the thermal protector is connected to the neutral point, the impedance of the motor limits the current flowing through the thermal protector , no limit short circuit test is required.
6 Withstand voltage test
The thermal protector installed in the motor should be able to withstand the motor withstand voltage test specified in GB755. 7 Installation and use conditions
The motor manufacturer should provide the thermal protector manufacturer with all information on the installation of the thermal protector in the motor. The material used to make the thermal protector should have sufficient strength, rigidity, insulation and heat resistance. GB1323291
Thermal Inspection Whether the protector meets the installation and use conditions shall be tested by agreement between the thermal protector manufacturer and the motor manufacturer. 7.1 The thermal protector installed before the motor windings are collapsed and dried shall be heated by the motor manufacturer according to the type test requirements. The protector is installed in the motor without damaging or weakening the motor insulation. The thermal protector shall meet the requirements specified in Articles 7.1.1 and 7.1.1. Thermal protector and its stress caused by winding processing and handling. The connecting wire (including insulation) should be able to withstand the following conditions without changing its operating characteristics: the temperature when the winding is dried;
a.
The mechanical stress when the thermal protector is embedded in the winding; b .
The mechanical stress on the thermal protector during subsequent winding processing and handling; c.
d. Impregnating agent specified by the motor manufacturer;
e Vacuum or pressure impregnation process (such as The motor manufacturer has regulations). Note: During the winding processing, the stresses generated by various factors are related to each other. See Article 9.9 for the test of individual factors. ||7.1.2 Mechanical stress generated during use
The thermal protector and its connecting wires should be able to withstand the alternating stress caused by winding temperature changes, electric power and mechanical vibration without changing its operating characteristics. .
Note: The motor manufacturer should correctly select the thermal protector. The mechanical details should be agreed between the motor manufacturer and the thermal protector manufacturer. 7.2 Thermal protection after the motor winding is impregnated and dried. The motor manufacturer shall install the thermal protector in the motor according to the type test requirements without damaging or weakening the motor insulation. The thermal protector and its connecting wires shall be able to withstand conditions caused by temperature changes, mechanical vibration and electric power (if any). alternating stress without changing its operating characteristics.
Note: The motor manufacturer should correctly select the thermal protector. The relevant mechanical details should be agreed between the motor manufacturer and the thermal protector manufacturer. 7.3. Thermal performance
7.3.1 High temperature performance
The thermal protector and its connecting wires should be compatible with the insulation structure of the protected motor and be able to withstand the temperature inside the motor without changing during operation its characteristics.
7.3.2 Low temperature performance
If there are no other provisions, the thermal protector should be able to operate well at the minimum ambient temperature specified in GB755, and can be stored at a temperature of -40℃ without damage and There are no permanent changes to the action characteristics. 7.4 Influence of magnetic field during use
The thermal protector installed in the motor or embedded in the winding is usually affected by the magnetic field of the location. When specifying the installation method and installation location, the motor manufacturer should consider the influence of the magnetic field and verify it through type testing. 8 Mark
Thermal protector should have the following mark:
manufacturer name, registered trademark or other marks indicating the manufacturer. If the thermal protector is only used for motors produced by our factory, there is no need to mark the manufacturer's name.
Product number or corresponding design mark, electrical ratings and temperature characteristics. The marking of the thermal protector's connecting wire should be in accordance with the agreement between the thermal protector manufacturer and the motor manufacturer. If it has been installed in the motor, it should be in accordance with GB/T13002 Article 6.2.2.
9 Type test
9.1 Test conditions
9.1.1 Test circuit voltage
GB13232-91
Thermal protector or thermal protector together with the motor The test circuit voltage should be 105% of the rated voltage of the motor. 9.1.2 Ambient temperature during test
If there are no other provisions, the test shall be conducted at an ambient temperature of 10 to 40°C. 9.1.3 Thermal protector sample
The thermal protector whose temperature nominal value tolerance does not exceed the tolerance range specified in Articles 5.1 and 5.2 is a typical sample. Typical specimens should be used for type testing.
When the temperature tolerance of the thermal protector agreed between the manufacturer and the manufacturer exceeds the provisions of Article 5.1 or 5.2, or exceeds both provisions, the test specified in this standard and GB/T13002 shall be carried out according to the following steps: Select a thermal protector with a disconnection temperature of the maximum nominal value and install it into the motor for all tests. In addition, for the automatic reset thermal protector, select a sample with a disconnection temperature of the minimum nominal value and install it into the motor for testing. Tests specified for rapidly changing thermal overloads.
The exact reset temperature of the specimen is not specified in the above test, but its value should be within the agreed tolerance range. Note: Selecting specimens with maximum tolerance for tripping temperature will provide test data to determine the maximum tripping temperature. In addition, for automatic reset thermal protectors, selecting samples with the largest and smallest tolerances for disconnection temperature can provide information to ensure that the thermal protector with a wide tolerance has sufficient action life for fast-changing thermal overloads. 9.2 Temperature characteristic test
Use any of the following methods to conduct the test
Method 1: Oil bath method
Immerse the thermal protector under test in the oil tank. The test conditions are: the capacity of the oil tank is at least 1000 times the volume of the thermal protector being tested; the depth of the thermal protector being tested should be greater than 75mm; the oil in the tank is evenly stirred, but no turbulence is generated. Method 2: Hot air drying oven method
The drying oven is an insulated closed pipe, with an air flow with adjustable temperature flowing inside, and the flow rate should be greater than 200m/min. The thermal protector under test is fixed in the furnace together with the necessary temperature measuring elements. The structure of the oil tank and drying furnace should be designed to prevent the thermal protector and temperature measuring element being tested from being affected by thermal radiation from the heat source. The temperature measuring device may use a thermocouple or other reliable and applicable device. The hot end of the thermocouple shall be attached to the temperature sensing element of the specimen or to another identical thermal protector close to the specimen.
When repeating the test, the thermocouple should be placed in the same position corresponding to the thermal protector under test. Tests that require changing the temperature of oil or hot air to determine the operating temperature of the thermal protector should start at a temperature about 10K higher or lower than the operating point. When approaching the operating temperature, the temperature change rate should not exceed 0.5K/min. Note: The test is carried out according to the above conditions. The effect of the two methods is the same. Which method to use depends on the structure of the thermal protector and the equipment conditions of the manufacturer.
9.2.1 Rated disconnection temperature test
Increase the oil temperature in the oil tank or the flowing air temperature in the drying furnace until the thermal protector under test operates. The measured operating temperature shall comply with the requirements of Article 5.1.
During the test, appropriate methods can be used to indicate the disconnection or connection of the thermal protector. However, the current through the thermal protector should not exceed 0.01A or a lower value specified by the thermal protector manufacturer. 9.2.2 Reset temperature test
Reduce the oil temperature in the oil tank or the air flow temperature in the drying furnace until the thermal protector is reset. The measured operating temperature shall comply with the requirements of Article 5.2.
The method and requirements for displaying the action of the thermal protector are the same as Article 9.2.1. 9.3 Rated tripping current test
GB13232-91
The thermal protector under test is placed in still air. Its support method and test circuit wiring method are determined by the thermal protector manufacturer and the motor manufacturer. Agreement between the parties.
The ambient temperature is maintained at 25±2℃, and the thermal protector is supplied with rated tripping current. Measure the time from connecting the circuit until the thermal protector trips. The measurement results should comply with the manufacturer's time requirements. 9.4 Manual reset thermal protector free tripping action test Manual reset thermal protector should be tested according to Article 9.3 and the tripping time should be recorded. When the thermal protector has cooled to the initial condition (preferably cooling for 24 hours), the test should be repeated. During the test, apply a force of 11N to the reset button before the current is turned on, and hold it until 3 seconds after the thermal protector trips. Compared with the first test results, the difference in tripping time should not exceed 2s.
The thermal protector should not be reset within the first 3 seconds after tripping, which is a sign of fast action. Successfully passing this test indicates that the thermal protector meets the requirements of Article 5.5. 9.5 Manual reset thermal protector low temperature performance test The thermal protector under test is connected to a device that can display the switch action (see Article 9.2.1). Starting from 5℃, gradually cool down the thermal protector at a rate not exceeding 0.5K/min, so that it can automatically reset or reach the 5th level.Clause 5 specifies the temperature (or a lower temperature as specified in the agreement).
The automatic reset temperature of the thermal protector shall not be higher than the lower temperature value specified in Article 5.5 or specified in the agreement. 9.6 Temperature characteristic test of thermal protector after installation After the thermal protector is installed in the motor, the motor manufacturer should conduct the following tests: For S2 to S9 working system motors, when using TP1×X or TP2XX type thermal protector, the following tests should be performed: The test content of Article 9.6.1 replaces Article 7.2 of GB/T13002.
The test content specified in Article 9.6.2 of this standard is a supplement to the content in Article 7 of GB/T13002. 9.6.1 Short-time or periodic duty motor
The motor shall run continuously under the conditions of rated load and voltage specified in Article 9.1.1. If the thermal protector operates and cuts off the motor power supply, the motor will run continuously. The time should exceed the time quota of the motor. If this requirement is met, the motor load should be gradually reduced and operated continuously to obtain the maximum load that the motor can withstand when the thermal protector does not operate. In order to achieve the specified operating conditions, the load can be reduced to no load if necessary, and the voltage can even be reduced.
If the thermal protector does not operate and the temperature of the motor winding is constant, the load should be increased to continue operation to determine thermal protection The maximum continuous load that the motor can bear when the controller is not operating.
When the motor is running under the maximum load where the thermal protector does not operate, the temperature of the motor should not exceed the value specified in Article 5.1 of GB/T13002.
9.6.2 Three-phase motors
Three-phase motors equipped with thermal protectors shall be tested under single-phase conditions in addition to the tests specified in Article 7 of GB/T13002.
9.6.2.1 The motor under test is equipped with a TP1XX or TP2XX thermal protector and operates under rated current and 105% rated voltage conditions. When the motor reaches normal operating temperature, disconnect one-phase power incoming line and conduct a single-phase operation slow-changing thermal overload performance test. The motor may immediately enter a stalled state or run for a short time before the thermal protector opens the circuit. If the maximum temperature of the motor after power outage does not exceed the corresponding value for fast-changing thermal overload specified in GB/T13002, the thermal protector performance is deemed to meet the requirements. The temperature of the motor of a manual reset thermal protector should not exceed the value specified in Article 5.2 of GB/T13002; the temperature of the motor of an automatic reset thermal protector should not exceed the value specified in Article 7.4 of GB/T13002 after 1 hour of operation. If the motor is still running after one phase is disconnected, the load should be gradually increased until the maximum load at which the thermal protector does not operate is determined. At this time, the maximum temperature of the motor should not exceed the corresponding value of slow-changing thermal overload specified in Article 5.1 of GB/T13002. 9.6.2.2 The single-phase operation fast-changing thermal overload performance test for motors equipped with TP2XX or TP3XX thermal protectors GB13232-91
shall be conducted as follows: For motors equipped with manual reset thermal protectors, the Turn on one phase of power supply and repeat the test of GB/T13002 Article 7.3.2. After the test, the maximum temperature of the motor should not exceed the value specified in Article 5.2 of GB/T13002. For motors equipped with automatic reset thermal protectors, one phase power incoming line should be disconnected and the test in Article 7.4 of GB/T13002 should be repeated for 2 hours. After the test, the maximum temperature of the motor should not exceed the value specified in Article 7.4 of GB/T13002. 9.6.3 Withstand voltage test
After completing the tests in Articles 9.6.1 and 9.6.2 above, the motor equipped with a thermal protector shall undergo a voltage withstand test in accordance with Article 6.2 of GB755.
9.7 Life test
This test is conducted by the motor manufacturer.
During the test, lock the motor rotor. According to JB2455 Article 8.2.4.1, the motor shell is grounded through a copper wire fuse with a diameter of 0.1mm and a length of not less than 50mm. The life test should be regarded as the continuation of the action cycle under the motor stall condition specified in GB/T13002, except that the motor winding temperature is not measured. 9.7.1 Manual reset thermal protector
In addition to the 10 action cycles specified in GB/T13002 Article 7.3.2, the thermal protector should also open the circuit 50 times without being affected by the motor stall condition. damage. The thermal protector should be reconnected as soon as possible after disconnecting the circuit. The motor should not suffer any dangerous damage, such as excessive insulation degradation.
At the end of the test, the sample underwent a total of 60 action cycles. 9.7.2 Direct-acting reset thermal protector
In addition to the 72h test specified in GB/T-13002 Article 7.4, the thermal protector should also operate for 15d without damage under the motor stall condition. The motor should not suffer any dangerous damage, such as excessive insulation degradation. At the end of the test, the total test time of the sample is 18d. 9.7. Motors above 30.8kW equipped with automatic reset thermal protectors. Motors above 0.8kW equipped with automatic reset thermal protectors. If they cannot complete 2000 action cycles within 18 days, additional tests shall be conducted on the thermal protectors so that the total The test action cycle should reach at least 2000 times. Additional testing can be continued on the motor, or the following methods can be used:
If it has been confirmed that a certain motor insulation structure is suitable for the same or higher rotor stall temperature, a simulated load can be used to thermal protector A separate life test (at least 2000 cycles) is carried out, but the cycle rate of the action (on-off time) should be the same as the cycle rate installed on the motor. If there is another agreement between the thermal protector manufacturer and the motor manufacturer, the action cycle rate can also be increased. During the test, the current should be equal to or greater than the locked-rotor current of the corresponding motor, and the power factor should be 0:4~0.5. 9.7.4 Criteria for motor damage
The criteria for dangerous damage to the motor are: ||tt ||Ground fault, such as a blown fuse as indicated in 9.7; Severe or persistent smoke or fire;
Insulation becoming brittle, charred or peeling;
Accessories (such as capacitors or starting relays) occurring can cause dangerous electrical or mechanical malfunctions. Note: Insulation discoloration cannot be considered as excessive deterioration. Insulation that becomes brittle or charred to the point where the insulation material can fall off when the motor winding is rubbed with fingers should be considered as excessive insulation deterioration.
9.8 Extreme short-circuit test
9.8.1 Motors using fast-acting fuses
Unless otherwise required by the user, fast-acting fuses should be used to protect the motor. According to the agreement, the following tests can be carried out by the thermal protector manufacturer or the motor manufacturer.
Take three thermal protector samples and connect them to the test circuit according to the provisions of Article 5.7.1 to withstand the current of the circuit. The power factor of the test circuit is 0.9~1.0.
GB13232--91
The capacity of the test circuit should be determined without connecting a thermal protector. During the test, the thermal protector can be installed into the protected motor, or the thermal protector can be tested separately, but the shell of the test device should be equal to or smaller than the motor shell. Wrap the thermal protector shell with medical absorbent cotton wool. The thermal protector is connected in series with a fast fuse, and the rated current of the fuse should be greater than 4 times the rated current of the motor. If the voltage is 150V and below, the rated current of the fuse should not be less than 20A; if the voltage is higher than 150V but not more than 660V, the rated current should not be less than 15A. There should be a manual reset thermal protector among the three specimens - one specimen shall be used for a closed short-circuit test, and the test circuit shall be short-circuited by connecting through the thermal protector.
If the outer cotton wool of the automatic reset thermal protector is not ignited during the test, the action should be repeated until the thermal protector permanently disconnects the circuit or the fuse blows. Allow the thermal protector to chip or the contacts to weld. The cotton wool wrapped around the thermal protector shell should not be ignited. Note: If there is another agreement between the thermal protector manufacturer and the motor manufacturer, it is allowed to use voltages and currents greater than those specified above or use larger fuses for testing. The test results are also valid for lower voltage and current values. 9.8.2 Equipment using fuse groups
In combined equipment driven by multiple motors, each motor may be equipped with a thermal protector. The size of the fuse in the circuit of the combined equipment is greater than that specified in Article 9.8.1.
If the user specifies that the motor is used in equipment equipped with a fuse group, the following additional tests should also be carried out. The thermal protector under test is connected in series with a quick fuse whose specifications are greater than those specified in Article 9.8.1, and the test is carried out in accordance with the provisions of this Article, except that a layer of bleached gauze (roving cloth) is used instead of skimmed cotton wool to wrap around the sample shell. The unit mass area of ??bleached gauze is 26~23m/kg, and there are 11 13-count yarns per square centimeter (or replaced with cloth close to it). 9.9 Inspection of installation and usage conditions
The test can be conducted by the thermal protector manufacturer, the motor manufacturer, or both parties jointly. The test content depends to a large extent on the design of the thermal protector, the design of the motor, and the installation method and location of the thermal protector inside the motor. The specific test content should be agreed between the thermal protector and the motor manufacturer and is not specified in this standard. 10 Inspection test
10.1 Rated disconnection temperature test
The test is carried out by the thermal protector manufacturer during the manufacturing process to ensure that the rated disconnection temperature of the thermal protector is within the specified tolerance range. 10.2 Reset temperature test
The test is carried out by the thermal protector manufacturer during the manufacturing process to ensure that the reset temperature of the thermal protector is within the specified tolerance range. 10.3 Test of manual reset thermal protector
The test is carried out by the thermal protector manufacturer during the manufacturing process to ensure that the manual reset thermal protector can trip freely and cannot automatically reset when the temperature is higher than -5℃ .
10.4 Withstand voltage test
Conduct a withstand voltage test according to the requirements of Article 6.2 of GB755. Since this test is conducted by the motor manufacturer on the entire finished motor (including the thermal protector), the thermal protector manufacturer is responsible for conducting necessary inspection tests to ensure that the thermal protector can pass the final test after being installed into the motor. .
GB13232-91
Appendix A
Guidelines for Selection of Thermal Protectors
(Supplement)
A1 For many motors of similar design and manufacture, When thermal protectors of the same type of design are used as components or integrally formed with the motor, repeated tests can be reduced. This can only be considered by the motor manufacturer and stipulates a set of procedures to select a thermal protector with suitable performance. The following details should be considered in motor manufacturing: a.
b.
c.
d.
e.
f.||tt| |g.
h.
i.
Motor rating;
Motor insulation level;
Installation method and installation of thermal protector in motor Position; limit temperature of slow-changing thermal overload motor windings; limit temperature of fast-changing thermal overload motor windings; electrical strength;
creepage distance and clearance;
life;
short circuit resistance performance.
Thermal protector adaptability items include:
a.
b.
c.
Selection of rated operating temperature and tolerance;| |tt||Material;
Structure;
d. Logo.
The first 9 details are related to the combination of motor and thermal protector. The insulation level and dielectric strength are related to the motor and should be determined by the motor manufacturer. The life of the A2 thermal protector can be determined by a breaking arc test under a suitable load. During the test, it is usually measured by the number of action cycles of the thermal protector and calculated into the fast-changing thermal overload of the motor and thermal protector combination ( the total time the rotor is locked). The performance obtained through this test can be directly used to specify the life of the thermal protector. A3 In order to evaluate the ultimate short-circuit performance, the thermal protector can be installed outside the motor for testing. Therefore, its enclosure should withstand the same or greater intensity of spark discharges and possible splashing of molten metal. The characteristics obtained through this test can be directly used to specify the short-circuit resistance performance of the thermal protector.
A4 The limit temperatures of fast-changing and slow-changing thermal overload motor windings can be determined using the characteristic curve set of the thermal protector series. This curve group involves the relationship between the critical tripping current of the thermal protector and the ambient temperature and the relationship between the first tripping time and the current at the specified ambient temperature. Before using this information to reduce repeated testing, the motor manufacturer should incorporate these thermal protector information into the application program and clearly specify that a certain series of thermal protectors is suitable for a certain series of motors. Likewise, the procedure should ensure that requirements such as creepage distances, clearances, dielectric strength and ultimate short-circuit performance are met. Additional notes:
This standard is proposed and centralized by the National Technical Committee for Standardization of Rotating Electrical Machines. This standard is drafted by Shanghai Electrical Equipment Research Institute and Guangzhou Electrical Equipment Research Institute. The main drafters of this standard are Guo Zhongbo, Yang Jieqi, Liu Ji and Tan Bicheng.
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