239 MOTOR PROTECTION RELAY

1. 239 Relay Features

The GE Multilin 239 relay is designed to fully protect three phase AC motors against

conditions which can cause damage. In addition to motor protection, the relay has

features that can protect associated mechanical equipment, give an alarm before

damage results from a process malfunction, diagnose problems after a fault and allow

verification of correct relay operation during routine maintenance. Using the ModBus serial

communications interface, motor starters throughout a plant can be connected to a

central control/monitoring system for continuous monitoring and fast fault diagnosis of a

complete process.

One relay is required per motor. Since phase current is monitored through current

transformers, motors of any line voltage can be protected. The relay is used as a pilot

device to cause a contactor or breaker to open under fault conditions; that is, it does not

carry the primary motor current. When the over temperature option is ordered, up to 3

RTDs can be monitored. These can all be in the stator or 1 in the stator and 2 in the

bearings. Installing a 239 in a motor starter for protection and monitoring of motors will

minimize downtime due to process problems.

2 Typical Applications

Versatile features and simple programming controls make the 239 an ideal choice for

motor and equipment protection in a wide range of applications. In addition to basic

electrical protection for motors, the 239 can protect against common faults due to process

problems, such as:

1. Mechanical protection of pumps using the undercurrent feature to detect loss of

suction or a closed discharge valve.

2. Mechanical protection of fans against loss of air flow in mines or flow in steam

generating boilers using the undercurrent feature.

3. Electrical protection of compressor motors from excessive run up time caused by an

open outlet using the start timer.

4. Mechanical protection of gears, pumps, fans, saw mill cutters, and compressors

against mechanical jam using the mechanical jam trip feature.

5. Safety to personnel from shock hazard using the ground fault feature to detect

winding shorts from moisture.

6. Protection of motors and equipment from operator abuse using the thermal memory

lockout.

Cost savings are provided using versatile features such as:

1. Diagnostic information after a trip to identify problems and bring the process back on

line quickly.

2. Fault indication of ground fault without shutdown to warn that corrective

maintenance is required.

3. Simplified spare parts stocking and initial specification design using one universal

model for many motor sizes, applications and settings.

4. Serial communication using the popular Modbus protocol to remotely monitor all

values, program setpoints, issue commands and diagnose faults to minimize process

disruptions.

5. Output of motor current suitable for programmable controller interface (4 to 20 mA).

MODIFICATIONS

• MOD 500: Portable test/carrying case

• MOD 501: 20 to 60 V DC / 20 to 48 V AC control power

• MOD 504: Removable terminal blocks

• MOD 505: Enhanced start protection

• MOD 506: Custom programmable overload curve

• MOD 509: Directional ground sensing with 120 V AC polarizing voltage

• MOD 512: 1 AMP Ground CT input

• MOD 513: Class 1 Division 2 operation

• MOD 517: Australian Mines approval

ACCESSORIES

• 239PC Windows software (supplied free)

• Phase and ground CTs

• RS232 to RS485 converter (required to connect a computer to the 239 relay(s) to run

239PC)

• RS485 Terminating Network

• 2.25” collar for limited depth mounting (1009-0068)

• Large size (8.5 x 11”) instruction manual (free upon request)

CONTROL POWER

• 90 to 300 V DC / 70 to 265 V AC standard

• 20 to 60 V DC / 20 to 48 V AC (MOD 501

1. MODEL NO: The model number shows the configuration of the relay. The model

number for a basic unit is 239. RTD and AN will appear in the model number only if the

RTD option or Analog Output option is installed. H will appear in the model number if

conformal coating is required.

2. SUPPLY VOLTAGE: Indicates the 239 power supply input configuration. The 239 shown

above can accept any AC 50/60Hz voltage from 70 to 265 V AC or DC voltage from 90

to 300 V DC.

3. TAG#: This is an optional identification number specified by the customer.

4. MOD#s: These are used if unique features have been installed for special customer

orders. These numbers should be available when contacting GE Multilin for technical

support. Up to five MOD#s can be installed into the 239.

5. SERIAL NO: Indicates the serial number for the 239 in numeric and barcode format.

The following table shows the revision history of the 239. Each revision of the instruction

manual corresponds to a particular firmware revision in the 239. The instruction manual

revision is located on the first page of the manual as part of the manual P/N (1601-00XXRevision).

The 239 firmware revision is loaded in the relay and can be found by scrolling to

the display message A3: PRODUCT INFOFIRMWARE VERSIONSMAIN PROGRAM

VER.

When using the manual to determine relay features and settings, ensure that the revision

corresponds to the 239 firmware revision using the table below. For a large instruction

manual (8.5” × 11”) the part number is 1601-0067; for a small instruction manual (5.5” ×

7.25”) it is 1601-0060

CONTROL POWER (36/37)

A universal AC/DC power supply is standard. It covers the range 90 to 300 V DC and 70 to

265 V AC at 50/60 Hz. It is not necessary to make any adjustment to the relay as long as

the control voltage falls within this range. A low voltage power supply is available upon a

request of MOD# 501. It covers the range 20 to 60 V DC and 20 to 48 V AC at 50/60 Hz.

Verify from the product identification label on the back of the relay that the control voltage

matches the intended application. Connect the control voltage input to a stable source of

supply for reliable operation. A 2.5 A fuse is accessible from the back of the unit without

opening the relay by sliding back the fuse access door.

PHASE CT INPUTS (1-9)

Current transformer secondaries of 5 or 1 A can be used for current sensing. Each phase

current input has 3 terminals: 5 A input, 1 A input, and common. Select the 1 or 5 A

terminal and common to match the phase CT secondary. Observe the polarity indicated in

the TYPICAL WIRING DIAGRAM, otherwise current measures incorrectly for the 2-phase or

residually connected CT configurations.

CTs should be selected to be capable of supplying the required current to the total

secondary load which includes the 239 relay burden mentioned in Section 1.2:

Specifications at rated secondary current and the connection wiring burden. The CT must

not saturate under maximum current conditions which can be up to 8 times motor full load

during starting or greater than 12 times during a short circuit. Only CTs rated for protective

relaying should be used since metering CTs are usually not rated to provide enough

current during faults.

GROUND CT INPUT (10/11/12)

Ground sensing terminals are labeled 5A, 50:0.025, and COM. Connection depend on the

grounding system and sensitivity required. For high resistance grounded systems that limit

the ground current or in mines where low levels of ground leakage must be detected, use a

separate CT to sense ground current. In this configuration, referred to as zero sequence or

core balance detection, all three phase conductors must pass through the CT window. If

the phase conductors are bundled in a cable with a ground, the ground wire must either

pass outside the ground CT window or be routed back through the window if it passes

through as part of the cable. Shielded and unshielded cable installations are illustrated in

the TYPICAL WIRING DIAGRAM. A ground CT with a ratio of 50:0.025 for sensing primary

ground currents from 0.05 to 15 A is available from GE. Connect this CT to terminals

50:0.025 and COM. If a conventional 5 A secondary CT is used for zero sequence ground

sensing, connect it to the 5A and COM terminals. A 1 A secondary CT can also be used;

however, to prevent readings from being off by a factor of 5, the ground CT primary

setpoint must be adjusted. See Section 4.3.1 CT Inputs on page 4–21 under GROUND CT

PRIMARY for suitable settings in this situation. Due to the low secondary currents, it is

recommended that the ground CT secondary leads be twisted together and routed to the

239 away from high current carrying conductors. NOTE: The 50:0.025 input is only

recommended for resistance grounded systems. Where the system is solidly grounded

or high levels of current are to be detected use the 5A ground input.

For low resistance or solidly grounded systems where higher ground fault currents will

flow, the phase CTs can be residually connected to provide ground sensing levels as low as

20% of the phase CT primary rating. For example, 100:5 CTs connected in the residual

configuration can sense ground currents as low as 20 A (primary) without requiring a

separate ground CT. This saves the expense of an extra CT however 3 phase CTs are

required. If this connection is used on a high resistance grounded system verify that the