Schneider LRD thermal overload relays

Protection function Overview: overload protection

Overload is the most common failure, which causes the current absorbed by the motor and the thermal effect to increase. After an overload occurs, you must return to normal operation as soon as possible.

In order to determine the operating value of the motor (power, current) and select effective overload protection, it is necessary to understand the actual operating conditions (ambient temperature, altitude of the work site and the type of standard load). These operating parameters are given by the motor manufacturer.

Depending on the level of protection required, protection functions can be provided in the following ways:

1. Overload relays and thermal overload relays (bimetal or electronic) can provide protection for the motor in the following aspects
2. Overload, by monitoring the current absorbed by each phase
3. Phase imbalance or phase break, through the differential principle
4. Relay with PTC thermistor detector (positive temperature coefficient)
5. Over-torque relay
6. Multi-function relay