Description
The GE Multilin MMII-PD-1-2-240 is a specific model number for the Motor Manager II (MM2), a digital, microprocessor-based protection and management relay designed for low-voltage electric motors. It is widely used in Motor Control Centers (MCCs) to consolidate functions like motor protection, metering, and control into a single unit.
Here is a breakdown of what this part number means, its technical specifications, and its core features:
Part Number Breakdown
- MMII: Motor Manager II series identifier.
- PD: Panel Mount with Display. The unit is physically mounted on the front panel of an MCC bucket or control cabinet door, featuring a built-in LCD screen and keypad for local configuration and monitoring.
- 1: Includes Option Package 1 (Adds features like process control, 10 programmable interlock inputs, undervoltage auto-restart, and diagnostics).
- 2: Includes Option Package 2 (Adds enhanced protection, power monitoring in kW, a thermistor input for temperature protection, and a second contactor control).
- 240: Designed for a 240 V AC control power supply.
Core Protection & Control Features
The MM2 replaces traditional, discrete components (like thermal overload relays, timers, and ammeters) with digital intelligence:
- Motor Protection: Monitors and protects against overloads, phase unbalance/single-phasing, ground faults, locked rotor/stalls, and high motor winding temperatures (via thermistor).
- Contactor Diagnostics: Actively checks the status of the contactor. It will trip and sound an alarm if it detects a welded contactor or an open control circuit during a start/stop command.
- Undervoltage Auto-Restart: If the control power drops momentarily, causing the contactor to drop out, the MM2 can use pre-set timers to automatically and safely restart the motor once stable power returns.
- Pre-Configured Control Logic: Includes built-in logic for standard motor starter types, such as Full Voltage Non-Reversing (FVNR), Full Voltage Reversing (FVR), and Wye-Delta starters.
Technical Specifications
| Parameter | Specification |
| Manufacturer | GE Multilin (now GE Vernova) |
| Control Supply Power | 240 V AC (\pm15\%), 50/60 Hz |
| Inputs | 16 total (6 fixed control inputs, 10 programmable interlock inputs) |
| Outputs | 4 total (2 contactor relays, 2 user-programmable auxiliary relays) |
| Communications | RS485 port supporting Modbus RTU protocol (1,200 to 19,200 bps) |
| Metering Parameters | Phase current, ground fault current, thermal capacity used, power (kW), and total energy (kWh) |
| Accuracy | \pm2\% for current and power measurements |
Lifecycle & Support Note
Product Status: The GE Multilin MM2 series is a legacy product line and has been phased out (discontinued) by the manufacturer. It has largely been replaced by the newer MM300 or M60 series.
Because it is obsolete, brand new units are rarely available directly from GE. Replacement parts, front panel overlays, and spare MMII-PD-1-2-240 units are typically sourced through industrial automation surplus vendors, authorized asset rebuilders, or specialized repair facilities.
Are you looking to replace an existing unit, troubleshoot a specific fault code (like an overload or ground fault trip), or do you need a wiring diagram for the terminal blocks?
