An SSOLR initiates a trip if the phase currents exceed what percentage of the trip current dial setting?

An SSOLR (Solid State Overload Relay) is designed to monitor the current flowing through a motor and to trip if the current exceeds a certain threshold, which is predetermined by the settings on the device. Typically, the trip current dial setting represents a specific value at which the SSOLR will activate to protect the motor from excessive current that can lead to overheating or failure.

In most cases, SSOLRs are designed to trip when the phase currents exceed 125% of the trip current dial setting. This percentage provides a balance between allowing for normal inrush currents or temporary overloads that might occur during startup or under heavy load conditions while still ensuring protection against prolonged overcurrent that could damage the motor.

The choice of 125% is practical, as it enables the protection system to account for short-duration spikes that are not harmful, yet still triggers a trip for excessive ongoing current that may endanger motor integrity or safety. Therefore, when the phase currents reach or exceed 125% of the set trip current, the SSOLR will initiate a trip, ensuring the motor is safeguarded against damage.