GE 139 SERIES MOTOR PROTECTION RELAY

GE 139 SERIES MOTOR PROTECTION RELAY

Product Overview

Functional features: All-round protection of three-phase AC motors, with overload, blocking, single-phase/unbalance, 

ground fault and other protection functions, but also diagnose faults, emergency restart and verification of relay operation status.

Application Scenarios: Suitable for a variety of industrial scenarios, such as pumps, fans, compressors and other equipment protection, 

can prevent equipment failure caused by personnel safety issues and equipment damage.

Relay selection: Horizontal and vertical mounting versions are available, depending on the application requirements and the type of 

current transformer (CT) (1A or 5A). Some features are optional and must be specified at the time of ordering.

Installation Guide

Physical dimensions and mounting: The relay is housed in a high-impact plastic case with a dust cover. 

The mounting is recessed and secured to the panel by U-clips. Check the options and switch settings on the product specification card before mounting.

External Connections: Connections include power supply, CT input, main relay contacts, etc. Some connections are optional. 

The power supply has two options, AC and DC, and the CT secondary side needs to be grounded.

CT Connection: One CT is required for each phase of the motor, and the secondary side of the CT should match the current of the relay. 

5A CT has a specific connection method, and 1A CT can be adapted to the 5A CT design of the relay by changing the wiring method.

Other connections: earth fault CT for earth fault detection, main and auxiliary relay contacts for control and alarms, 

external reset and emergency restart functions can be realised with specific terminals, options such as temperature sensing, 

thermal capacitance meter and current outputs have corresponding connections.

Setup and use

Control and Indication: Parameters are set via the front panel control. Indicator lights are used to show the operating status of the relay and fault information.

Parameter setting: including maximum load control, unbalance control, undercurrent control, start timer setting, etc. 

Each parameter should be adjusted according to the actual situation of the motor.

Function options: Programmed by internal selector switch, such as cyclic overload compensation, immediate overload warning, emergency restart, 

memory function, etc., which can be switched on or off according to the application requirements.

Special functions: Ground fault protection can be set with different trip currents and delay times; 

over-temperature protection is realised by RTD sensors, which can be set for alarm and trip temperatures; 

the thermal capacity meter and 4 - 20mA output function are optional for easy monitoring and control.

Relay Testing

Test equipment: Commercial secondary injection test equipment or homemade test circuits can be used to test relays.

Test Items: Including overload, start timer, unbalance, undercurrent, ground fault, over-temperature and other functional tests, 

the test should pay attention to simulate the actual working conditions and operating specifications.

Daily maintenance verification: Regular testing can check the correct operation of the protection system, 

simulate various fault conditions for testing to ensure that the relay works properly.

Troubleshooting: Possible causes and solutions are provided for common fault symptoms, such as relays failing to reset, frequent overload trips, and so on.

Working Principle: Each phase current is isolated and converted by CT, then sampled and amplified by electronic switch. 

Fault judgement such as overload, unbalance, undercurrent is achieved by comparing with preset reference value. 

Overload timing is controlled by an integrator circuit with different charging rates in start-up mode. 

Alarm functions are implemented by separate relays, with separate detection and comparison circuits for RTD and earth fault alarms.