Overload Protection Relay (OPR) is a crucial electrical device designed to safeguard motors and various electrical equipment from the hazards of overcurrent situations. Overloading can lead to excessive heating, insulation breakdown, and in severe cases, catastrophic failures, resulting in costly downtime and potential safety hazards. This article delves into the workings, types, applications, and selection criteria of overload protection relays, emphasizing their significance in electrical systems.
The Working Principle of Overload Protection Relays At its core, an overload protection relay functions by monitoring the current flowing through a motor or electrical equipment. It continually compares this current against predefined threshold values set by the user. When the current exceeds these thresholds for a sustained period or beyond a set time delay, the relay triggers an action to disconnect the power supply to prevent damage. Current Sensing： The device incorporates current sensors that track real-time electrical current. These sensors might be embedded in the relay or installed externally, capturing any deviations from normal operating conditions.