Industrial Controls

Electronic Overload Relay

Electronic Overload Relay has a peculiar tripping characteristic as per the designated CLASS. The tripping characteristic is an Inverse exponential curve of I (Current) Vs T (Tripping Time).

Efficient Micro controller unit (MCU) is used to monitor all activities & take the necessary decisions based on that to implement the proper actions.


This device is used to protect 3-phase motors from over current, single phasing & other such phenomena.

In any of the above cases, the Electromechanical Relay used in the device trips & switches off the motor to protect it. The CT module is of 2 separate CTs fitted on to the device to continuously monitor current flowing through the respective phase. If any unbalancing occurs, the corrective feedback in-turn is given by MCU to act accordingly.

I Vs T is the curve (as per international standard) that states higher the current lesser is the tripping time.


Electronic overload relay is suitable for AC 50/60Hz, voltage up to 600VAC and current up to 60A. It is used as Overload and Phase Loss Protection device. It has independently adjustable STARTING and TRIP delay (O-TIME, D-TIME), Visual Current Setting Dial, Trip Indication, Fail Safe Protection (N type) and Electronic Shear Pin function. The product conforms to IEC60947-1 standard.

EFR (Earth Fault Release)

These are Earth Leakage Testers used to detect leakage current in ground terminal of equipment. The device is CT-based. Tripping mechanism is provided by means of an electro-mechanical sealed relay.

  1. It’s a compact device & not bulky as thermal overload relay. Weight is very less.
  2. It has got intelligent electronic brain to take decisions.
  3. The actions initiated by micro controller are sharp & precise (including the tripping time).


    Tripping Range


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  4. It can monitor single phasing phenomenon.
  5. Thermal memory provision is made available electronically.
  6. It monitors & records frequent current fluctuations on the supply lines and act accordingly.
  7. Features like cold-state running of motor & hot time tripping are also incorporated in it.
  8. It can be used in amalgamation of a contactor & can in-turn switch on & off the contactor.
  9. Cost wise very much cheaper to the thermal overload relay.
For details, please contact factory.