Standard Motor Catalog

Section TR Technical Reference Guide

STARTING CURRENT, LOWER THAN STANDARD The starting current code (KVA-per-horsepower) for polyphase 60 HZ motors in the integral-Hp sizes is typically code G. Reducing the amount of starting current to code F limits or lower may require more material, increased frame size or a combination of these factors. Starting torque and breakdown torque may also be reduced to less than NEMA design B limits. SURGE PROTECTION Surge Capacitors and Surge Arrestors (Lighting Arrestors) Surge protection capacitors and lighting arrestors can be supplied on 500 frame motors as a package in an oversize conduit box for mounting adjacent to the motor. Surge capacitors and Lighting Arrestors are used to protect the motor from voltage spikes on the power line. Surge capacitors are available without surge arrestors. Surge arrestors are available only with surge capacitors. TEMPERATURE RISE, SPECIAL NEMA has defined allowable winding temperature rise according to class of insulation and maximum ambient temperature. Where there are requirements for special low winding temperature rise, please contact the Company for review of the available options. TERMINALS, SPECIAL All motors, except as mentioned below are supplied with ring terminal (illustrated in Figure 25): • Non-XSD Ultra Motors in Frames 140-280, will be supplied with lead wire stripped for connection to power leads.

Table 18

Max Full Load Amps

Frames 143-286 143-286

Bolt Size


160 250

5/16"-18 UNC 3/8"-16 UNC 0.500-13 UNC 0.500-13 UNC 0.500-13 UNC

1 1 2 1 2



324-5013 324-5013



LEADS, SPECIAL All motors are provided with standard leads of ample length for easy connection in the conduit box to the power leads. Lead size and material are dependent upon the class of insulation system in the motor and the current capacity required. Longer than standard leads are available on request. SPACE HEATERS Space heaters are used to prevent moisture condensation in the motor when it is not running. They are generally mounted on the opposite connect end of the stator on the OD of the end turns. GE space heater kits are designed to raise the temperature of winding 6.5 to 9 degree C above the ambient with an initial rate of rise 3.5 degree C per hour. They are suitable for use on both single phase AC and DC voltage supplies. Surface temperature during operation is approximately 200 degrees C. Special Div II Space Heaters: GE Power Conversion has developed and patented a thermostatically controlled space heater. These heaters are provided with hermetically sealed thermostat so they only operate with a maximum surface temperature of 140 degree C and do not spark in an end of life event. In order to limit surface temperature rise during operation, these heaters operate at watt densities significantly lower than standard heaters. The thermostat limits the maximum temperature resulting from motor residual temperature (occurring as a result of motor operation), ambient temperature, and space heater temperature. During continued normal operation with a 40 degree C ambient, the surface temperature will remain below the thermostat setting; which will increase the life of the heater. The thermostat opening temperature might be exceeded due to high ambient and/or motor residual temperatures. In most cases when a motor is shut down, the space heaters are immediately turned on. As the motor may take many hours to cool down, the heaters being automatically turned on can result in a cumulative hear that may result in temperatures that approach the 80% Auto-Ignition Temperature or AIT limit. A thermostatically controlled heater will not allow the heater to energize until the motor has sufficiently cooled down (below 140°C thermostat reset temperature) thereby not allowing the temperatures to exceed the stated AIT.

Figure 25: Ring Terminal

Leads range in size from 18 gauge to 8 gauge depending on the amount of current that the motor produces. THERMAL PROTECTION - WINDING The following devices are applicable only to motors with class F or H insulation with class B or F temperature rise. Built-in protective devices to prevent motor overheating may be either: (A) Line interrupting devices which open the power supply when the motor overheats or (B) pilot devices. The latter open the holding coil circuits of a magnetic switch to take the motor off the line, or energize alarm bells or warning lights. Motors taken off line by pilot devices typically cannot be restarted until an operator recloses the magnetic starting switch.


Data subject to change without notice. 02/23 •

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