GE Multilin MM2 Motor Manager 2 Manual

The official operation manual of GE Multilin MM2 Motor Manager 2 (firmware/software V5.2x) is a low-voltage motor integrated protection and control device, which integrates a complete set of motor protection such as three-phase overload, locked rotor, ground fault, under/over voltage, thermistor, etc. It supports 13 types of starter control, RS485 Modbus RTU communication, and panel/remote/software triple operation. Parameter configuration, real-time monitoring, fault diagnosis, and maintenance statistics are achieved through the front panel keyboard+LED+20 × 2 display screen. It is suitable for MCC motor control centers and has industrial grade features such as expandable I/O, programmable logic, under voltage self start, and user-defined memory mapping, meeting the needs of motor safe operation and intelligent monitoring.

Product basic information

MM2 (Motor Manager 2) is a low-voltage motor comprehensive protection controller launched by GE Multilin, used in MCC motor control centers to achieve integrated protection, control, monitoring, and communication.

Firmware/Software Version: V5.2x

Manual Number: 1601-0056-DU (GEK-106294F)

Power supply: 120/240V AC, 50/60Hz

Installation: Panel installation (with display), rack installation (black box type)

Certification: UL, CE, ISO9001:2000

Environment: 0-60 ℃, IP53，NEMA 12

Hardware structure

1. Front panel

Display: 20 × 2 character LCD

LED: operation, shutdown, tripping, alarm, fault, contactor A/B, auxiliary relay, automatic/manual

Keys: Set value, actual value, store, stop, reset, start A/B, message/numerical value up, down, left, right

2. Input/output interface

Type and specification

Current input three-phase CT (1A/5A), grounding CT (5A/50:0.25)

Voltage input VT input 120V AC, maximum 600V

Switch input 120V AC optocoupler isolation, up to 10 programmable channels

Analog input 4-20mA, accuracy ± 1% FS

Relay output contactor A/B, auxiliary 1/2, contact capacity 10A/240V AC

RS485 communication, 2-wire half duplex, Modbus RTU

3. Core hardware

Main CPU: 16 bit 68HC16, 16MHz

Backup CPU: 68HC705, power-off timer ≥ 1 hour

Sampling: 1.67ms true RMS

Storage: EEPROM saves parameters, not lost in case of power failure

Protection function (S2 configuration)

Covering all types of motor faults, with high accuracy and precise action time

thermal overload protection

Curve: 8 standards+4 NEMA CLASS (10/15/20/30)

Accuracy: ± 200ms (≤ 10s), ± 2% (>10s)

Thermal model: Cold to heat ratio of 20% to 100%, shutdown cooling time of 5 to 1080 minutes

Ground fault protection

Detection: Residual/Zero Sequence CT, 50:0.025 High Sensitivity Type

Threshold: 0.1~15A or 3%~100% CT

Action delay: 0-10s (set separately for startup/operation)

locked-rotor protection

Threshold: 1.15~4.50 × FLC

Delay: 0.5~5s

Other protections

Phase failure/imbalance:>30% imbalance, 5-second action

Under/Over Voltage: 0~600V, Delay of 1~60s

Underload/underpower: 10%~100% FLC, delay of 1-60s

Thermistor: PTC/NTC, 100~30000 Ω

Control function (S1/S4 configuration)

Supports 13 types of initiators

Full voltage irreversible/reversible, dual speed, star delta (open/closed loop), autotransformer, wound rotor, series resistor, frequency converter, soft start, backup interlock

control mode

Two line/three line, manual/automatic, local/remote, interlock control

Under voltage self starting

Instant restart: 100~500ms

Delayed restart: 0.2~30s

Power down memory time: up to 1 hour

Programmable input

10 configurable channels: interlocking, lock reset, automatic permission, testing, remote permission, etc

Monitoring and Maintenance (S5/A Real Value)

real-time data

Three phase current, grounding current, voltage, power, load rate, thermal capacity, imbalance

statistical data

Duration of operation/shutdown, number of starts, various trip counts, interlock counts

Maintenance reminder

Motor lubrication interval: 100~50000h

Contactor inspection: 1000~1000000 times

Maximum shutdown alarm: 10-10000 hours

Communication (Modbus RTU)

electrical interface

RS485， 2-wire half duplex, up to 4000 feet long, up to 32 units

Baud rate: 1200/2400/4800/9600/19200

Support function code

01H: Reading coil

03H/04H: Read Register

05H: Execute Command

06H: Write a single set value

10H: Write multiple set values

memory mapping

Real value range: 0000~0FFF

Set value area: 1000~1FFF

User defined area: 0100~0177, 1280~12F7

Installation and Testing

Install

Panel opening: 7.50 × 7.10in (191 × 180mm)

Wiring: CT strictly prohibits open circuit, communication shielding is grounded, terminal resistance is 120 Ω

test

First/Second Injection Test

Current, imbalance, grounding, thermal sensitivity, and power failure tests

Control wiring

Two wire/three wire, manual/automatic/interlocking, emergency stop

Software Tool (MM2PC)

Function: Parameter reading and writing, configuration saving, firmware upgrade, real-time monitoring

Connection: RS232/485 converter

Applicable to: Windows system, provided for free

Key issues

Question 1: What are the core advantages of MM2 compared to traditional motor relays?

Answer: The core advantage is integrated protection, which combines overload, grounding, locked rotor, undervoltage, thermal sensing, imbalance and other full protection, 13 starter controls, real-time monitoring, and Modbus communication into one device; Supports programmable I/O, under voltage self start, power-off thermal memory, user-defined memory, higher accuracy (RMS sampling), more comprehensive protection, remote monitoring, significantly reducing MCC wiring and maintenance costs.

Question 2: What are the two connection methods for ground fault protection of MM2 and what scenarios are they applicable to?

answer:

5A secondary CT/residual connection method: suitable for conventional grounding systems, sensitivity 5% motor CT, low cost, strong universality.

50:0.025 High sensitivity zero sequence CT: suitable for high resistance grounding systems, can detect 0.1A level low current grounding, provide early insulation warning, and avoid false tripping.

Question 3: How many Modbus communication devices can be connected to MM2 at most? What core operations are supported and how can communication stability be ensured?

answer:

Up to 32 devices can be connected via daisy chain, with a communication distance of 4000 feet.

Core operations: read and write set values, read real values, remote start stop, reset trip, circuit testing.

Stability measures: Shielded wire single ended grounding, terminal 120 Ω resistor+1nF capacitor, correct polarity, avoid star wiring, baud rate matching.