Product Overview

The GE MMII-PD-1-2-120​ is the control-power and relay-output module at the heart of GE Multilin’s MMII family — Motor Management Integrated Intelligence. It is not a stand-alone motor protector and it is not a current transformer; it is the plug-in sub-module that marries a 120 VAC control supply to a single Form-C (SPDT) output contact, giving an MMII-equipped motor starter one clean, rated switching path for trip, alarm, seal-in or aux contact duty. In a typical medium-voltage or large LV starter, the MMII sensing head does the measuring — phase loss, reverse phase, overload, locked rotor, jam, underload, current unbalance — and the GE MMII-PD-1-2-120​ is what actually reaches out and interrupts the control circuit or lights the annunciator when the algorithm says stop.What makes the GE MMII-PD-1-2-120​ more than a convenient relay-in-a-box is the way it inherits the MMII’s decision logic instead of duplicating it. A conventional starter uses a thermal overload relay plus a separate phase-loss relay plus a separate seal-in contactor aux, and every one of those devices has its own reset philosophy and its own wiring. The MMII collapses that stack into one sensing and logic platform, then presents the outcome on a small, field-replaceable relay module whose contact rating is honest enough to carry the trip circuit directly. One MMII-PD-1-2-120​ therefore removes a handful of DIN-rail devices, a coil’s worth of panel heat and several metres of inter-device wiring from the starter cubicle — and it does it without introducing a PLC dependency into a safety-critical trip path.The “1-2-120” naming is the whole product story, and it is worth reading aloud before you order. The first digit is the relay count: 1​ means one output relay. The second digit is the contact form: 2​ means Form C, an SPDT changeover with normally-open and normally-closed poles, so the contact can be wired either fail-trip or fail-safe depending on the starter philosophy. The suffix 120​ is the control-power voltage, 120 VAC, 50/60 Hz. A site standardising on 240 VAC control power would reach for the same family with the -240 suffix; a site that needs two independent output functions — say trip plus alarm, or trip plus breaker-failure supervision — steps up to the MMII-PD-1-3-120, which carries three Form-C relays in the same footprint. That gradation is deliberate: GE priced the platform so the panel builder buys exactly the contact count the motor needs, not the nearest oversized option.Physically the module is a compact, plug-in industrial assembly with the GE Multilin house style — conformal-coated logic, a robust relay element, and a housing that snaps into the MMII mounting envelope. It is a mature, end-of-life product now, which is why the aftermarket is littered with mislabeled “MMII relay” listings that conflate the PD power/relay module with the sensing head. The distinction matters: a GE MMII-PD-1-2-120​ will not function without its MMII host, and an MMII host with no PD module fitted has no way to switch the starter.

Technical Specifications