Ms. was chatting with her friend, Xiao M, when they mentioned that the rotor leads of a wound- rotor motor sold by their company were experiencing grounding issues. Xiao M had the design department staff analyze the problem carefully and discovered that the motor was not manufactured using leads with the specified voltage.
Motor lead wires are an important component of motor products. Different motors require different types of cables due to their inherent characteristics and specific operating conditions. Because of the special process of impregnating motor leads and windings with enamel, there are industry standards that specify the characteristic requirements for motor cables. Ms. Can has compiled some relevant requirements for cables used to directly and permanently connect to the motor windings and extend them out of the housing or windings, directly connecting to the motor terminals, and is sharing them with you.
Requirements for impregnation
Cables typically undergo the same treatment as connected components, including immersion in impregnating varnish and subsequent baking. Although type testing of cables includes heat effect testing and impregnating varnish resistance testing, users should still provide the cable manufacturer with information regarding the grade of the impregnating varnish and the baking and curing treatment to further clarify the cable's suitability.
Temperature-related content
The highest conductor temperature during continuous operation of a cable is unrelated to the "hottest" temperature of the machinery or equipment to which the cable is connected. The heat resistance classification of motor insulation involves the hottest temperature of the coil winding, while the leads at the coil ends are typically fixed at the lowest point of the coil winding temperature. The temperature of the leads at the coil ends is generally lower than the temperature of the stronger winding to which they are connected.
The table below lists typical cable selections based on the motor insulation temperature rating. However, accurate cable selection requires consideration of various factors, such as product design, product performance, and qualification tests for relevant installation conditions.
Commonly used motor cable types, names, and characteristics
● Flexible cables and wires with a maximum conductor temperature of 70°C during continuous operation
Corresponding standard: JB/ T6213.2
JV PVC insulated motor winding lead cable (wire)
JF Nitrile Polyvinyl Chloride Composite Insulated Motor Winding Lead Cable (Wire)
Usage characteristics: AC rated voltage is 500V; maximum continuous operating conductor temperature is 70℃; the allowable bending radius during cable (wire) laying should not be less than 4 times the outer diameter of the cable (wire).
● Flexible cables and wires with a maximum conductor temperature of 90°C during continuous operation
Corresponding standard: JB/ T6213.3
JE EPDM rubber insulated motor winding lead cable (wire)
JEH EPDM rubber insulated, chlorosulfonated polyethylene sheathed motor winding lead cable (wire)
JEM EPDM rubber insulated, chloroprene sheathed motor winding lead cable (wire)
JH Chlorosulfonated Polyethylene Insulated Motor Winding Lead Cable (Wire)
Usage characteristics: The AC rated voltage of the cable (wire) is 500V, 1000V, 3000V, 6000V and 10000V; the maximum continuous operating conductor temperature is 90℃; the bending radius of the cable (wire) during laying should not be less than 4 times the outer diameter of the cable (wire).
● Flexible cables and wires with a maximum conductor temperature of 180°C during continuous operation
Corresponding standard: JB/ T6213.4
JG silicone rubber insulated motor winding lead cable (wire)
Usage characteristics: The AC rated voltage of the cable (wire) is 500V, 1000V, 3000V, 6000V and 10000V; the maximum continuous operating conductor temperature is 180℃; the bending radius of the cable (wire) during laying should not be less than 4 times the outer diameter of the cable (wire).
●Freon-resistant flexible wire
Corresponding standard: JB/ T6213.5
JZ polyester insulated fluorine-resistant motor winding lead wire
JF46 polytetrafluoroethylene propylene insulated, fluorine-resistant motor winding lead wire
Usage characteristics: The rated AC voltage of the cable (wire) is 500V; the allowable bending radius of the cable (wire) during installation should not be less than 4 times the outer diameter of the cable (wire).
● Flexible cables and wires with a maximum continuous operating conductor temperature of 125°C and 150°C
Corresponding standard: JB/ T6213.6
JYJ125 125℃ Cross-linked Polyolefin Insulated Motor Winding Lead Cable (Wire)
JYJ150 150℃ Cross-linked Polyolefin Insulated Motor Winding Lead Cable (Wire)
Usage characteristics: The AC rated voltage of the cable (wire) is 500V (only this voltage is available for JYJ150 type cable), 1000V and 3000V; the maximum continuous operating conductor temperature of JYJ125 type cable (wire) is 125℃, and the maximum continuous operating conductor temperature of JYJ150 type cable (wire) is 150℃; the allowable bending radius of the cable (wire) during laying should not be less than 4 times the outer diameter of the cable (wire).
JB/ T6213.1-6213.6 are a series of standards for motor lead wires, specifying the standards and specific requirements for dedicated lead wires for different motors and operating conditions. Motor manufacturers should select and use lead wires correctly according to the actual motor requirements to prevent quality problems caused by improper selection and use. JB/ T6213.1 addresses general requirements for cables used in motors, while the others specify special requirements for different insulation classes or operating conditions.
