Encapsulated electric motor with temp. sensors - may be used in explosive environment and may use thyristor or voltage and frequency control

摘要

Explosion protected electric motors partic. thyristorised dc motors and also voltage-and frequency-controlled three-phase current motors, use ignition-protection type 'd' pressure-tight encapsulation primary protection is provided by semiconductor temperature sensors. To enable the max. excess temperatures for the control or regulation range to be sensed at points on the motor housing, the cooling action, with water cooling, of the stator wall, or with surface cooling, via an externally powered blower or fan, is monitored via the semiconductor temperature sensors located at the points on the motor housing surface that show or indicate the highest excess temperatures. With falloff in the cooling the most rapid rise in temperature is also indicated by the semiconductor temperature sensors. The upper permissible temperature threshold dependent of providing explosion protection is not exceeded for each operational mode or phase of the motor.