The electrical performance of a rotary electric motor is defined by the condition of the rotor and the stator coils. The motor must be protected with alarms and triggers against operating conditions that are not considered normal. This is for electrical or mechanical operations.
Some of these protections when installed allow the machine to be restarted directly when the fault is detected.
Some protections when activating the alarm need further investigation, such as:
- High bearing temperature;
- High temperature in the coil or in the cooling air;
- Overload, current and voltage unbalance, overvoltage;
- Vibration protection.
Temperature detectors are an indispensable part of the monitoring and protection system of the machine and they are used to measure the temperatures of the windings, bearings and in the cooling air.
The detector uses a platinum filament for temperature measurement, and may be damaged for many reasons, such as improper handling or excessive vibration.
Factors that can cause a problem in the temperature detector are infinite or zero resistance in the detector, the disappearance of the measurement signal during or after starting and a significantly different resistance value in a single detector. https://www.mrosupply.com/hydraulics-and-pneumatics/hose-reels/2517102_shw-n-150_coxreels/