JB/T 7836.1-1995 General technical requirements for electric heaters for motors
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Electric heater for motor
1 Subject content and scope of application
General technical conditions
JB/T7836.1—1995
This standard specifies the classification technical requirements, test methods, inspection rules, marking, packaging, transportation and storage requirements of electric heaters for motors (hereinafter referred to as electric heaters) and their electric heating elements (hereinafter referred to as electric heating elements). This standard applies to electric heaters installed inside motors or in their pits. 2 Reference standards
GB755—87 Basic technical requirements for rotating motors GB998—82 Basic test methods for low-voltage electrical appliances GB3836.1—83 General requirements for explosion-proof electrical equipment for explosive atmospheres
GB4208—93 Enclosure protection grade
Wet heat test requirements for motors used under general environmental conditions GB12665—90
JB/T2379—93 Metal tubular electric heating element JB4159-85 General technical requirements for tropical electrical products 3 Terms
Terms specific to this standard are defined as follows:
3.1 Electric heating element
An independent assembly consisting of an electric heating conductor and its accessories 3.2 Tubular electric heating element
An electric heating element with a metal tube as the outer shell, an alloy electric heating wire as the heating element, a lead rod at one or both ends, and an electric insulating medium with good thermal conductivity tightly filled in the metal tube to fix the heating element. 3.3 Finned tube electric heating element
An electric heating element with a metal tubular electric heating element as the base, extruded or tightly wound with metal sheets on the surface. 3.4 Finned tube electric heater
An electric heater assembled from finned tube electric heating elements. 3.5 Electric heating element outer shell
The outer surface of the electric heating element.
3.6 Electric heater
A complete electric heating device assembled from electric heating elements. 3.7 Sufficient heating conditions
Working conditions that enable the electric heating element to reach the specified working state. 3.8 Working temperature
The average temperature of the outer surface of the electric heating element under rated power and sufficient heating conditions, approved by the Ministry of Machinery Industry on November 24, 1995
Implementation on June 1, 1996
4 Product classification
JB/T7836.1—1995
4.1 Electric heaters are divided into the following two categories according to the use environment of the product: ordinary type·Classification code \DR\;
Explosion-proof type.Classification code \DBR".
4.2 Electric heater type code and its meaning
XXX/XX
Rated power W/rated voltage V
Classification of electric heating elements, see Table 1
"Explosion-proof electric heater for motors" Code Table 1|| tt||Classification code of electric heating element
4.3 Main technical parameters
Rated voltage, V;
Rated power, W;
Rated frequency, Hz;
Working temperature.℃;
Appearance and structural dimensions, mm.
5 Technical requirements
5.1 Design requirements
5.1.1 Environmental conditions
Altitude shall not exceed 1000m;
Ambient air temperature shall be -20℃～50℃;
Relative humidity of ambient air shall not exceed 90% (when ambient temperature is 25℃). Name
Indicates that the electric heating element is a smooth tubular
Indicates that the electric heating element is a warped tubular
Indicates that the electric heating element is a plate Shape
Indicates that the electric heating element is strip-shaped
When the environmental conditions of actual application exceed the specified range, it can be determined by negotiation between the supply and demand parties. 5.1.2 Rated voltage
The rated voltage of the electric heater is: 220V, 380V. If the user has special requirements, it can be determined by negotiation between the supply and demand parties. 5.1.3 Rated frequency
The rated frequency of the electric heater is 50Hz.
If the user has special requirements, it can be determined by negotiation between the supply and demand parties. 5.1.4 Rated power
The rated power of the electric heating element is: 50, 100, 160, 200, 250, 400, 630, 800W. The power of the electric heater is obtained by combining the electric heating elements according to actual needs. For the selection of the power of the electric heater, please refer to Appendix A Rotating Electric Prevention of moisture absorption of winding insulation in the machine (reference). If the user has special requirements, it can be determined by negotiation between the supply and demand parties. 667
5.1.5 Structure
JB/T7836.1-1995
5.1.5.1 When designing electric heating elements, the effects of thermal expansion and oxidation should be considered to avoid failures due to deformation during normal operation. 5.1.5.2 Electric heating elements should adopt a closed structure. 5.1.5.3 The shell of the electric heating element should be made of materials with good thermal conductivity. 5.1.5.4 The shell of the electric heating element should be installed with a grounding bolt, which should be made of stainless material or electroplated for rust prevention. 5.1.5.5 The protection level of the shell of the electric heating element should not be lower than the IP54 requirement in the GB4208 standard. 5.2 Manufacturing requirements
The manufacture of electric heaters should be in accordance with the design drawings approved by the prescribed procedures and meet the requirements of product standards and relevant technical documents. 5.2.1 The outer shell of the electric heating element shall not have significant mechanical damage or local expansion, and shall avoid depressions, sharp edges or corners to prevent corrosion due to water accumulation and dust accumulation.
5.2.2 The plating layer of the electroplated part shall be uniform and smooth, and there shall be no peeling or local accumulation. 5.2.3 The lead-out rod of the electric heating element shall be able to withstand a 3-minute tensile test without displacement or breakage. The test tensile force is 70% of the tensile strength of the lead-out rod, but not more than 1000N.
5.3 Performance requirements
5.3.1 Rated power deviation
Under rated voltage and full heating conditions, the allowable deviation of the input power of the electric heater and electric heating element shall not exceed the following specified range:
For rated power of 100W and below: ±10%. For rated power of more than 100W: +5% to -10%, or 10W, whichever is greater. 5.3.2 Leakage current
The leakage current of the electric heating element shall comply with the following provisions: 5.3.2.1 After the cold leakage current and enclosure grade test, the leakage current shall not exceed 0.5mA. 5.3.2.2 The hot leakage current at the operating temperature shall not exceed the calculated value of the following formula, but the maximum shall not exceed 2mA. LT×10-$
Where: 1—hot leakage current, mA;
L heating length, mm;
T—operating temperature, C.
5.3.3 Overload capacity
(1)
The electric heater (or electric heating element) shall be able to withstand 30 cycles of overload test under the specified test conditions and input power without damage.
5.3.4 The requirements for the operating temperature, cold and hot insulation resistance, insulation withstand voltage strength, and moisture and heat resistance of the electric heater (or electric heating element) shall be in accordance with the specific product standards.
5.3.5 Working life
The working life of the electric heater shall not be less than 3000h. 6 Test method
6.1 The power-on test of the electric heater (or electric heating element) shall be carried out under the following conditions: a. The ambient air temperature is (20±5)℃, there is no wind and no strong heat radiation, and the relative humidity is not more than 85%; b. The test voltage deviation does not exceed ±1% of the rated value; c. The electric heater (or electric heating element) is in full heating conditions or simulated conditions. 6.2 Shell protection level test
The shell protection requirements of the electric heating element shall be carried out in accordance with the test methods specified in GB4208. 668
6.3 Lead-out rod tensile test
JB/T7836.11995
Fix the electric heating element, then hang the set weight (including the accessories required to hang on the lead-out rod) vertically on the lead-out rod, and conduct the inspection after 3 minutes.
6.4 Rated power
The rated power should be measured with a power meter, voltmeter or ammeter 10 minutes after the electric heater (or electric heating element) is in full heating conditions or simulated conditions and reaches the working temperature. The accuracy of the measuring instrument should not be lower than Class 1.5. 6.5 Leakage current measurement
The accuracy of the milliammeter used in this test should not be lower than Class 1.5. 6.5.1 The leakage current measurement test after the cold state and enclosure protection level test should be carried out without power. Insulate the enclosure of the electric heating element from the ground, and then apply the test voltage between any lead rod of the electric heating element and the enclosure. The current measured by the milliammeter connected to the connecting line is the leakage current. The test voltage Us is 1.1 times the rated voltage.
The schematic diagram of the test circuit is shown in Figure 1.
6.5.2 Hot leakage current measurement
The test should be carried out when the electric heating element is powered on and reaches the working temperature. Connect the electric heating element to the power supply, adjust the test voltage Us so that the input power is equal to 1.15 times the rated power, and start measuring the leakage current 10 minutes after the electric heating element reaches the working temperature. During the measurement, the leakage current should be measured at the lead wires at both ends through the conversion of the switch K, and the larger value should be taken as the standard for assessment.
The schematic diagram of the test circuit is shown in Figure 2.
6.6 Insulation resistance measurement
JB/T7836.1—1995
This test is measured with a 500V megohmmeter. During the test, the housing of the electric heating element and the megohmmeter shall not form a loop through the ground to avoid affecting the measurement accuracy. At the same time, the impact of the environment on the measurement accuracy should be considered. The megohmmeter should be connected between any lead rod and the housing of the electric heating element. 6.6.1 Cold insulation resistance measurement
Cold insulation resistance measurement should be carried out 24 hours after the electric heating element is provided. 6.6.2 Hot insulation resistance measurement
The test should be carried out when the electric heating element is at the working temperature. Turn on the power supply to make the electric heating element reach the working temperature and keep it for 10 minutes, then turn off the power supply, and complete the measurement within 1 minute after the power is turned off. No forced cooling method to cool the electric heating element shall be used within this 1 minute. 6.7 Overload test
Connect the electric heater (or electric heating element) to the power supply, and adjust the voltage to make the input power reach the specified value. Charge for 1 hour under full heating conditions, then turn off the power and cool to room temperature for 0.5 hours (forced cooling is used if necessary). The number of cycles of on and off is 30 times. For products with a rated power of no more than 100W, the input power of the overload test is 1.3 times the rated power; for products with a rated power of more than 100W, the input power of the overload test is 1.27 times or 1.21 times the rated power plus 12W, whichever is greater. 6.8 The working temperature measurement, insulation withstand voltage test, and moisture and heat resistance test of electric heaters (or electric heating elements) shall be carried out in accordance with the relevant provisions of the specific product standards.
6.9 Working life test
6.9.1 Test conditions
The electric heater shall be installed on the test stand in the normal working position, and the fixing of the electric heater and the support of the test stand shall conform to the actual use conditions.
6.9.2 Test method
The electric heater shall be passed with 1.1 times the rated voltage, and the cumulative working time until damage is accumulated after it stabilizes. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery shall be tested according to the specified factory test items. Each product must be inspected and approved by the enterprise's quality inspection management department, and must be accompanied by a product certificate or have a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products that are trial-produced should be subjected to type testing if any of the following conditions are met;
When there are major changes in design, process or materials; Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6bZxz.net
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products to repeat the test of the item. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The outside of the packaging box should have durable and obvious text and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a closed motor is raised by 5°C above the ambient temperature. The approximate value of the heat required is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)15 times, and start measuring the leakage current 10 minutes after the electric heating element reaches the working temperature. During the measurement, the leakage current should be measured at the lead wires at both ends through the conversion of switch K, and the larger value should be taken as the standard for assessment.
The schematic diagram of the test circuit is shown in Figure 2.
6.6 Insulation resistance measurement
JB/T7836.1—1995
This test is measured with a 500V megohmmeter. During the test, the shell of the electric heating element and the megohmmeter shall not form a loop through the ground to avoid affecting the measurement accuracy. At the same time, the impact of the environment on the measurement accuracy should be considered. The megohmmeter should be connected between any lead rod and the shell of the electric heating element. 6.6.1 Cold insulation resistance measurement
Cold insulation resistance measurement should be carried out 24 hours after the electric heating element is provided. 6.6.2 Hot insulation resistance measurement
The test should be carried out when the electric heating element is at working temperature. Connect the power supply to make the electric heating element reach the working temperature and keep it for 10 minutes, then disconnect the power supply and complete the measurement within 1 minute after the power is disconnected. No forced cooling method to cool the electric heating element shall be used during this 1 minute. 6.7 Overload test
Connect the electric heater (or electric heating element) to the power supply, and adjust the voltage to make the input power reach the specified value. Charge it for 1 hour under full heating conditions, then disconnect the power supply and cool it to room temperature for 0.5 hours (forced cooling is used when necessary). The number of cycles of power on and off is 30 times. For products with a rated power of no more than 100W, the input power of the overload test is 1.3 times the rated power; for products with a rated power of more than 100W, the input power of the overload test is 1.27 times the rated power or 1.21 times the rated power plus 12W, whichever is greater. 6.8 The working temperature measurement, insulation withstand voltage test, and moisture and heat resistance test of the electric heater (or electric heating element) shall be carried out in accordance with the relevant provisions in the specific product standards.
6.9 Working life test
6.9.1 Test conditions
The electric heater should be installed on the test frame in the normal working position. The fixing of the electric heater and the support of the test frame should conform to the actual use conditions.
6.9.2 Test method
The electric heater is passed with 1.1 times the rated voltage. After stabilization, the time of its working until damage is accumulated. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery must be tested according to the specified factory test items. Each product must be inspected and qualified by the enterprise's quality inspection management department and accompanied by a product certificate or a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products to be trial-produced shall be subject to type test if any of the following conditions are met;
When there are major changes in design, process or materials;Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products and repeated tests of the item shall be carried out. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The packaging box should have durable and obvious words and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a closed motor is raised by 5°C above the ambient temperature. The approximate value of the heat required is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)15 times, and start measuring the leakage current 10 minutes after the electric heating element reaches the working temperature. During the measurement, the leakage current should be measured at the lead wires at both ends through the conversion of switch K, and the larger value should be taken as the standard for assessment.
The schematic diagram of the test circuit is shown in Figure 2.
6.6 Insulation resistance measurement
JB/T7836.1—1995
This test is measured with a 500V megohmmeter. During the test, the shell of the electric heating element and the megohmmeter shall not form a loop through the ground to avoid affecting the measurement accuracy. At the same time, the impact of the environment on the measurement accuracy should be considered. The megohmmeter should be connected between any lead rod and the shell of the electric heating element. 6.6.1 Cold insulation resistance measurement
Cold insulation resistance measurement should be carried out 24 hours after the electric heating element is provided. 6.6.2 Hot insulation resistance measurement
The test should be carried out when the electric heating element is at working temperature. Connect the power supply to make the electric heating element reach the working temperature and keep it for 10 minutes, then disconnect the power supply and complete the measurement within 1 minute after the power is disconnected. No forced cooling method to cool the electric heating element shall be used during this 1 minute. 6.7 Overload test
Connect the electric heater (or electric heating element) to the power supply, and adjust the voltage to make the input power reach the specified value. Charge it for 1 hour under full heating conditions, then disconnect the power supply and cool it to room temperature for 0.5 hours (forced cooling is used when necessary). The number of cycles of power on and off is 30 times. For products with a rated power of no more than 100W, the input power of the overload test is 1.3 times the rated power; for products with a rated power of more than 100W, the input power of the overload test is 1.27 times the rated power or 1.21 times the rated power plus 12W, whichever is greater. 6.8 The working temperature measurement, insulation withstand voltage test, and moisture and heat resistance test of the electric heater (or electric heating element) shall be carried out in accordance with the relevant provisions in the specific product standards.
6.9 Working life test
6.9.1 Test conditions
The electric heater should be installed on the test frame in the normal working position. The fixing of the electric heater and the support of the test frame should conform to the actual use conditions.
6.9.2 Test method
The electric heater is passed with 1.1 times the rated voltage. After stabilization, the time of its working until damage is accumulated. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery must be tested according to the specified factory test items. Each product must be inspected and qualified by the enterprise's quality inspection management department and accompanied by a product certificate or a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products to be trial-produced shall be subject to type test if any of the following conditions are met;
When there are major changes in design, process or materials;Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products and repeated tests of the item shall be carried out. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The packaging box should have durable and obvious words and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a closed motor is raised by 5°C above the ambient temperature. The approximate value of the heat required is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)1 Cold insulation resistance measurement
Cold insulation resistance measurement should be carried out 24 hours after the electric heating element is provided. 6.6.2 Hot insulation resistance measurement
The test should be carried out when the electric heating element is at the working temperature. Turn on the power supply to make the electric heating element reach the working temperature and keep it for 10 minutes, then turn off the power supply, and complete the measurement within 1 minute after the power is turned off. No forced cooling method to cool the electric heating element shall be used during this 1 minute. 6.7 Overload test
Connect the electric heater (or electric heating element) to the power supply, and adjust the voltage to make the input power reach the specified value. Charge for 1 hour under full heating conditions, then turn off the power and cool to room temperature for 0.5 hours (forced cooling is used if necessary). The number of cycles of on and off is 30 times. For products with a rated power of no more than 100W, the input power of the overload test is 1.3 times the rated power; for products with a rated power of more than 100W, the input power of the overload test is 1.27 times or 1.21 times the rated power plus 12W, whichever is greater. 6.8 The working temperature measurement, insulation withstand voltage test, and moisture and heat resistance test of electric heaters (or electric heating elements) shall be carried out in accordance with the relevant provisions of the specific product standards.
6.9 Working life test
6.9.1 Test conditions
The electric heater shall be installed on the test stand in the normal working position, and the fixing of the electric heater and the support of the test stand shall conform to the actual use conditions.
6.9.2 Test method
The electric heater shall be passed with 1.1 times the rated voltage, and the time it works until it is damaged shall be accumulated after it stabilizes. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery shall be tested according to the specified factory test items. Each product must be inspected and approved by the enterprise's quality inspection management department, and must be accompanied by a product certificate or have a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products that are trial-produced should be subjected to type testing if any of the following conditions are met;
When there are major changes in design, process or materials; Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products to repeat the test of the item. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The packaging box should have durable and obvious words and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a closed motor is raised by 5°C above the ambient temperature. The approximate value of the heat required is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)1 Cold insulation resistance measurement
Cold insulation resistance measurement should be carried out 24 hours after the electric heating element is provided. 6.6.2 Hot insulation resistance measurement
The test should be carried out when the electric heating element is at the working temperature. Turn on the power supply to make the electric heating element reach the working temperature and keep it for 10 minutes, then turn off the power supply, and complete the measurement within 1 minute after the power is turned off. No forced cooling method to cool the electric heating element shall be used during this 1 minute. 6.7 Overload test
Connect the electric heater (or electric heating element) to the power supply, and adjust the voltage to make the input power reach the specified value. Charge for 1 hour under full heating conditions, then turn off the power and cool to room temperature for 0.5 hours (forced cooling is used if necessary). The number of cycles of on and off is 30 times. For products with a rated power of no more than 100W, the input power of the overload test is 1.3 times the rated power; for products with a rated power of more than 100W, the input power of the overload test is 1.27 times or 1.21 times the rated power plus 12W, whichever is greater. 6.8 The working temperature measurement, insulation withstand voltage test, and moisture and heat resistance test of electric heaters (or electric heating elements) shall be carried out in accordance with the relevant provisions of the specific product standards.
6.9 Working life test
6.9.1 Test conditions
The electric heater shall be installed on the test stand in the normal working position, and the fixing of the electric heater and the support of the test stand shall conform to the actual use conditions.
6.9.2 Test method
The electric heater shall be passed with 1.1 times the rated voltage, and the time it works until it is damaged shall be accumulated after it stabilizes. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery shall be tested according to the specified factory test items. Each product must be inspected and approved by the enterprise's quality inspection management department, and must be accompanied by a product certificate or have a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products that are trial-produced should be subjected to type testing if any of the following conditions are met;
When there are major changes in design, process or materials; Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products to repeat the test of the item. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The packaging box should have durable and obvious words and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a closed motor is raised by 5°C above the ambient temperature. The approximate value of the heat required is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)1 Test conditions
The electric heater should be installed on the test stand in the normal working position. The fixing of the electric heater and the support of the test stand should conform to the actual use conditions.
6.9.2 Test method
The electric heater is passed with 1.1 times the rated voltage. After stabilization, the time of its operation until damage is accumulated. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery must be tested according to the specified factory test items. Each product must be inspected and qualified by the enterprise's quality inspection management department and be accompanied by a product certificate or a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products to be trial-produced shall be subject to type test if any of the following conditions are met;
When there are major changes in design, process or materials;Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products to repeat the test of the item. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The outside of the packaging box should have durable and obvious text and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the approximate value of the heat required to raise the winding temperature of a closed motor by 5°C above the ambient temperature is determined by the following formula: A2
Where: H
Heat equivalent kW;
D Diameter of motor end shield (or end cover), m,
L Length between the two inner end faces of an end shield (or end cover), m. Additional notes:
This standard is proposed and managed by Harbin Large Electric Motor Research Institute. This standard was drafted by Beijing Heavy Electric Motor Factory, Beijing Ruiande Technology Development Company and Jiangyin Dianbo Electric Motor Instrument Factory. The main drafters of this standard are Xu Xiangmei, Chen Yinsheng and Han Linsheng. (Al)1 Test conditions
The electric heater should be installed on the test stand in the normal working position. The fixing of the electric heater and the support of the test stand should conform to the actual use conditions.
6.9.2 Test method
The electric heater is passed with 1.1 times the rated voltage. After stabilization, the time of its operation until damage is accumulated. 7 Inspection rules
7.1 Factory inspection
All products proposed for delivery must be tested according to the specified factory test items. Each product must be inspected and qualified by the enterprise's quality inspection management department and be accompanied by a product certificate or a qualified mark specified by the manufacturer before it can be released. The factory inspection items, requirements and methods are specified in Table 2. Table 2
Factory inspection items
Marking inspection
Appearance inspection
Cold insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Packaging inspection
Type test
New products to be trial-produced shall be subject to type test if any of the following conditions are met;
When there are major changes in design, process or materials;Technical requirements
Section 8 .1 Article
Article 5.2
Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 8.2
Test method
Article 6.6.1
Article 6.8
Article 6.4
Stop production for more than one year and then resume production;
JB/T7836.1—1995
d. For ordinary products produced in continuous batches, the test is conducted once every two years, of which the moisture and heat resistance test is conducted once every three years. For explosion-proof products, the relevant provisions of GB3836.1 shall be followed. 7.2.2 The components for type test shall be extracted from the products that have passed the factory inspection and have been packaged. 7.2.3 The products used for type test shall be divided into two groups, with two pieces in each group. The first group of type test items and their sequence are as specified in Table 3. Table 3
Type test items
Marking inspection
Design requirements inspection
Appearance inspection
Enclosure protection grade test
Cold leakage current measurement
Ling insulation resistance measurement
Cold insulation withstand voltage test
Rated power measurement
Hot leakage current measurement
Hot insulation resistance measurement
Hot insulation withstand voltage test Voltage test
Working temperature measurement
Overload test
Lead rod tensile test
Working life test
Note: Test No. 4 is only carried out when the product is finalized, technical requirements
Article 8.1
Articles 5.1.1~5.1.5.4
Article 5.2
Article 5.1.5.5
Article 5.3.2.1||tt ||Article 5.3.4
Article 5.3.4
Article 5.3.1
Article 5.2.2.2
Article 5.3.4
Article 5.3.4
Article 5.3.4
Article 5.3.3
Article 5.2.3
Article 5.3.5
Article 6.2
Article 6.5.1||t t||Article 6.6
Article 6.8
Article 6.4
Article 6.5.2
Article 6.6
Article 6.8
Article 6.8
Article 6.7
Article 6.3
Article 6.9
The second group of type tests is the moisture and heat resistance test, which shall be carried out in accordance with Article 6.8 of this standard and shall comply with the requirements of Article 5.3.4. 7.2.4 Products that have undergone type tests shall not be delivered as finished products. 7.2.5 In the type test, any product and any inspection item shall be qualified. If only one item of a component fails, the test shall be repeated, otherwise the batch of products shall be considered unqualified. For repeated tests, double the number of products shall be drawn from the batch of products and repeated tests of the item shall be carried out. As long as one product fails this item, the batch of products is considered unqualified. 8 Marking, packaging, transportation and storage
8.1 Electric heaters (or electric heating elements) should have the following permanent markings: a.
Product model;
Product factory date or product number.
For explosion-proof products, the relevant provisions of GB3836.1 shall apply. 8.2 Electric heaters (or electric heating elements) should be packed in packaging boxes. 8.2.1
The packaging box must contain a packing list, product factory qualification certificate and product instruction manual. The packaging box should have durable and obvious words and signs, including: manufacturer name; name and address of the consignee; product name and model; number of electric heaters (or electric heating elements): net weight, gross weight; box size; packing number; keep it light, dry, and moisture-proof; date of manufacture. JB/T7836.1—1995 If the user has special requirements for packaging, it can be determined by negotiation between the supply and demand parties. 3 Electric heaters (or electric heating elements) should be stored in a warehouse with good air circulation, no corrosive gases, relative humidity not more than 85%, and not subject to rain and snow.
JB/T7836.1-1995
Appendix A
Prevention of moisture absorption of winding insulation in rotating motors (reference)
A1 Motors that have been shelved for a long time will have their insulation resistance reduced due to moisture absorption. If the motor windings are heated to a temperature slightly higher than the ambient temperature by 5°C, moisture absorption of the winding insulation can be prevented.
2 When the motor is out of use, the winding temperature of a clos
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