Protector Trip Relays

Crompton Instruments manufactured extensive range of Protector Trip Relays (electronic control products)providing continuous monitoring and protection of any electrical parameter, including 400 Hz for the aviation industry. When the monitored parameter deviates from the desired set point limit, the relay will operate to prevent damage to the power asset. Designed to suit a wide variety of applications the range offers both traditional and technologically advanced products, from single parameter units through to multifunctional microprocessor based protection relays.

For the specific protection of generator sets, the range offers unbalanced current, reverse power flow, reverse VAr, synchro-check and under/over-speed trip relay functions. Various dc models provide protection of battery and UPS systems and a range of temperature protection products is ideal to prevent the damaging effects of overheating.

This versatile range features a host of DIN-rail protectors offering numerous trip functions for single and three-phase power systems, including (see pics below): Ac Current, Ac Voltage, Dc Millivolts, Earth Leakage, Frequency, Ground Fault, Hot Spot 3 Temperature, Hot Spot 6 Temperature, Phase Balance, Phase Sequence and Failure, Reverse Power, Speed Sensing, Synchro-Check(Paralleling), Thermistor Trip, Voltage & Frequency Combined Under/Over


Continuous monitoring of any electrical parameter
Monitoring for under and over current conditions
Ensures load current is within generator capacity
DIN-rail or wall mounted
Range of outputs and configurations
Adjustable trip points, time delay and differentials
LED trip indication
Designed to avoid nuisance tripping


Protection of power assets
Detection and isolation of faults
Maintains supply continuity of healthy circuits
High speed tripping to avoid damage


Aviation Industry (400 Hz Protectors)
Distribution systems
Generator sets
Control panels
Energy management
Building management
Utility power monitoring
Process control
Motor protection
Equipment and network protection


CSA File Number 052592 for following units
Ac Voltage, Types: 252-PV,253-PV, monitoring voltage, 300v max single phase and three phase
AC Current, Types: 252-PA, 253-PA, monitoring current, 5A max from CT secondary, 10 A max direct. Aux. voltage supply – 300V ac max, 24 V DC max, 4VA
Frequency, Types: 252-PH, 253-PH, monitoring frequency,400 Hz max, 300 v max
Reverse power, Type: 256-PA, monitoring voltage, 300 V ac max, monitoring current 10 A max
Phase Sequence-loss, Type: 252-PVR, monitoring voltage, 300 V max
Phase Balance, Type: 252-PS, monitoring voltage, 600 v ac max
Transducer Trip, Types: 252-PB, 253-PB, monitoring voltage 50 v DC, monitoring current 20 mA DC, Aux Voltage supply 240 v ac max, 3 VA
Temperature Trip, Types: 252-PBS, 253-PBT, monitoring voltage, 150 mv max. Aux voltage 240 v ac max, 3VA.
Synchro-Check, Type: 256-PLL, 256-PLD; monitoring voltage, phase displacement, and frequency of two supplies, operating voltage range 57.7-300v ac max, 45-65 Hz, 6VA with two output relay contacts rated 240 v ac, 5A (non-inductive) and 24 V DC/5A (resistive)