Protector Trip Relay - Three Phase, 4 wire Phase Sequence/Failure PVR4 100/120V, 173/240V or 380/480V

The phase sequence and phase failure protector trip relay is designed to monitor the correct phase rotation or sequence of a three-phase supply system. It provides electrical protection against incorrect phase sequence, loss of one phase and under voltage. Two versions are available to suit either three-phase three-wire (PVR3) or three phase four-wire (PVR4) systems.

Operation

Applications where the involvement of three-phase motors, which can rotate in the wrong direction, potentially could lead to physical damage or risk of injury to personnel, yet voltage and current readings may still appear normal. If one phase is lost because of a blown fuse, electric motors can continue to operate (singlephasing) which can result in severe electrical or mechanical damage. For permanent installations, this relay should be used to monitor the incoming supply, protecting all equipment against incorrect connection at initial installation or after maintenance work. Rotating machines that cannot tolerate reverse rotation or pose significant risk to personnel under this condition should be individually protected with this relay.

The phase sequence and phase failure protector continuously monitors the three-phase supply. With the correct phase sequence applied, the front panel LED will be off and the relay energised. An incorrect sequence or missing phase will de-energise the relay and the LED will illuminate showing a fault condition. The supply falling below 85% of its nominal voltage will also cause a trip.

Note: If one phase is lost due to a blown fuse, some loads can re-generate the missing voltage. This relay can be used as a phase failure relay providing the regenerated voltage in open phase is less than 70% of the nominal supply voltage. If there is the possibility of a higher regenerated voltage, the phase balance PSF should be used.

Basic Parameters

• Available with three voltage ranges 100-120V, 173-240V & 380-480V (Un)
• Adjustable nominal voltage range
• Power on LED (green)
• Fixed differential (hysteresis) 1%

Click the PDF below to read more about the Crompton Instruments Three Phase, Phase Sequence/Failure PVR Protector Trip Relay.