Protector Trip Relay - Reverse Power (Current) PAS PAT 100/120V, 173/240V or 380/480V

PA* Reverse Power (Current) Protection Relay

The Reverse Power Protector Trip Relay monitors a single- or three-phase supply for reverse power and trips a relay if it detects reverse power (I x cos Φ) over a set limit. The relay output is typically used to prevent ‘motoring’ of a generator (where the generator turns the engine), which can damage the engine.

Operation

The Reverse Power Trip Relay provides continuous surveillance of AC generators against motoring. Reverse power relays are used to detect the failure of the prime mover (engine) when active energy (Watts) flows into the generator causing rotation - the set will operate like an electric motor, which can cause significant mechanical damage. This relay offers an adjustable reverse power set between 2% and 20% of the nominal power and time delay adjustment range of 0 to 20 seconds. The protector relay estimates the power level in the system by measuring current and power factor, but does not actually measure the system voltage. When the reverse power level exceeds the set point, and after the time delay has elapsed, the relay will energise and the red LED will illuminate to indicate the trip condition. The relay will automatically reset once the power level falls below the set point minus the fixed differential of 1% causing the LED to extinguish and the relay to de-energise.

Note: The % set potentiometer trimmer on the front label is calibrated as a percentage of the current rating e.g. of 5A, and not of the forward kilowatts.

Basic Parameters

• Available with three voltage ranges 100-120V, 173-240V and 380-480V (Un)
• Adjustable nominal current range, 2, 3, 4, 5, 8 & 10 Amps (In)
• Adjustable trip delay 0.5-20s
• Adjustable set point 2-20%

Click the PDF below to read more about the Crompton Instruments Reverse Power (Current) PAS PAT Protector Trip Relay.