Ground Fault Protection

Overview

The ground-fault protection is used to protect asynchronous motors against ground fault conforming to the IEC 60947-4-1 and UL 60947-4-1 standards.

The protection type is Class A according to UL 60947-4-1 standard.

The ground-fault protection can be used to protect three-phase IE1, IE2, IE3, and IE4 asynchronous motors.

Ground fault occurs when the insulation drops on the load circuit due to vibration or moisture.

Settings

The table below shows the position of the rotary switch used to enable or disable the ground-fault protection.

	The ground fault protection is enabled. Ig = 0.75 Ir.
	The ground fault protection is disabled.

Operation

The overload relay calculates the ground current Ig continuously. When the ground current Ig exceeds more than 10%, the relay trips in 1±20% s.

Manual Reset

The ground fault protection can be reset manually only. For more information, refer to Trip Reset.