HEAT EXCHANGER 3M7916 - Caterpillar

Introduction
The reverse power relay (RPR) provides system protection when the genset is in parallel with other units. If for some reason the engine loses power, the other parallel unit attempts to motorize (drive electrically) the engine and generator. As long as voltage is present at the generator leads, the voltage regulator maintains the field excitation. The engine and generator remain magnetically coupled and the generator then drives the engine. Instead of power going OUT, power flows INTO the failing generator. This reverse flow of power could possibly result in overloading of the other generators and the whole system.The reverse power relay (RPR) is a single phase relay which is energized by power (amp-volts) in only one direction (power into generator instead of out). In a reverse power fault, the relay (RPR) (located on AC Schematic) closes its contact across RPR (5 and 6) (line 19) (located on DC Schematic). The GSC records an SP1 fault and the engine is shutdown. If the generator output breaker is equipped with shunt trip, the generator is taken off line. See the Schematics And Wiring Diagrams section.After the reverse power fault is corrected, the generator set control (GSC) is reset by turning the engine control switch (ECS) to the OFF/RESET position. Also reset the generator output breaker if equipped with shunt trip.The operation of the RPR is tested by pushing the test button on the RPR while the generator is on load. Depress and hold the test button for 10 to 15 seconds (until time delay elapses).
To avoid personal injury from electrical shock, do NOT touch the high voltage terminal while adjusting the reverse power relay.
The relay trip point is field adjustable, but is normally factory set at approximately 15% of the generator rated kW (for on-line generators operating at 15% or more of rated kW).Overvoltage Relay (OVR)
The overvoltage relay (OVR) is an option and mounts to the sub-panel within the control panel. The OVR provides system protection for line to line overvoltages. The OVR is a three phase relay with an adjustable pickup setpoint from 100 to 125% of its nominal rating. The setpoint also has an adjustable time delay from 0.5 to 20 seconds.If system voltage exceeds the setpoint for more than the time delay setting, then contacts 7 and 8 of the OVR will close. The generator set control (GSC) will record an SP1 fault and the engine is shutdown. If the generator set is equipped with an optional circuit breaker with shunt trip, the generator is taken off line. See the Schematics And Wiring Diagrams section.
To avoid personal injury from electrical shock, do NOT touch the high voltage terminals while adjusting the over voltage relay.
After the SP1 fault is corrected, the generator set control (GSC) is reset by turning the engine control switch (ECS) to the OFF/RESET position. If equipped with shunt trip, the generator output breaker must also be reset. The pickup setpoint and time delay are field adjustable. The pickup setpoint is factory set to the