Universal Trip Amplifier (PR 4179B)

The PR 4179B monitors AC current or voltage and switches relays when the value crosses a limit. Connected to a current transformer on a motor feeder, it detects an overloaded pump, a dry-running pump, a broken belt or a jammed conveyor by the change in motor current; connected across a heater or a supply, it detects a failed element, a blown fuse or an out-of-range voltage. It replaces a protection relay plus a signal converter in one module.

The input accepts AC current up to 5 A RMS or AC voltage up to 300 V RMS directly, without external converters. Two potential-free relay outputs are configured independently with set point, hysteresis, on and off delay and normally energised or de-energised operation, so one relay can alarm and the other trip. The universal power supply covers 21.6 to 253 VAC and 19.2 to 300 VDC. Configuration and readout use the detachable PR 4500-series display and programming interface, and the module mounts on a DIN rail, rated IP20.

Applications are monitoring of AC current and voltage signals, alarm generation and trip control in oil and gas, petrochemical, chemical, power and general process industries, typically in motor control centres, pump and compressor packages and heater panels.