Sensata® 4CR amperometric disconnectors


The 4CR relay uses an armature for providing positive operation.

The double switch contacts have excellent electrical and thermal conductivity for providing high switching capacity and electrical lifespan.

For 25 Amp contacts silver cadmium oxide is used.



The values shown indicate the maximum pick-up and minimum current drop-out.

Pick-up is the minimum current necessary fo closing the relay contacts. Drop-out is the minimum current required to alow the relay contacts to open.

A relay product with a certain rating will have a pick-up and drop-out current within the limit indicated. The 4 CR relay coil is in series with the main windings of the motor and the NO contacts are in series with the primary winding.

When a voltage is applied to the motor, the current flowing in the main winding passes through the relay coil creating a magnetic force that rotates the armature.

This action closes the relay contacts and excites the motor windings.

As the motor speed increases the current in the main windings and the relay coil decreases to the point where the polarisation of the armature is greater than the magnetic force of attraction and the armature rotates returning to its original position.

This opens the relay contacts and disconnects the starter windings.



115 Volt 10 Amp; 220 Volt 7 Amp


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