ICM402 – PHASE LOSS AND REVERSAL MOTOR PROTECTOR (HIGH CONTROL VOLTAGE)

ICM Controls 3-phase line voltage monitor that protects motors and compressors by continuously watching for phase reversal, phase loss and phase unbalance on a 190-600 VAC three-phase line. This is the line-voltage control version, taking 115 or 208/230 VAC control voltage, and it switches an SPDT relay rated 30 A N.O. Green ON and red FAULT LEDs indicate status, and the passive electronics are epoxy coated. Same protection as the ICM401A but with high control voltage instead of 24 VAC.

Specifications published by the manufacturer. Source: manufacturer documentation.

Specs

• Function3-phase monitor - reversal, loss, unbalance
• Line voltage190-600 VAC
• Control voltage115 or 208/230 VAC
• Frequency50/60 Hz
• OutputRelay, SPDT
• Contact rating30 A N.O.
• IndicatorsON and FAULT LEDs
• ConstructionEpoxy coated passive electronics
• Dimensions1.25" H x 3" W x 3.25" L
• Cross-reference (Supco)TPMP2
• Cross-reference (Mars)32536

Where does an HVAC surge protector go?

Hardwired at the outdoor disconnect, on the line side, not the load side. Line side keeps it working even when somebody pulls the block for service. Leads land in parallel across L1 and L2 with the green on the ground lug, and keep them short and straight, because extra length adds inductance and slows the clamping response. Shut off the breaker and pull the disconnect before you open the box.

What ratings should I look at?

Two numbers. Surge current capacity in kA is how much energy it can soak up before it is used up, and 25kA to 50kA per mode is a reasonable residential range. Voltage protection rating is what it lets through, and lower is better. Then look for a status light. Green means the metal oxide varistors are intact. Dark, red or amber means they are spent and the device is now just a box on the wall.

Do I really need one in Dallas?

More than most places. DFW gets spring and summer storm activity plus heavy grid load across a cooling season that runs March into October, and utility switching transients come with that territory. An inverter or communicating system with a variable speed board is far more sensitive to transients than an old single-stage unit, and one of those boards runs several hundred dollars against a protector that costs a fraction of it.

Will it protect against low voltage or brownouts?

No, and that is the myth worth killing. A surge protective device clamps spikes going up. It does nothing about sagging voltage, single phasing, rapid short cycling or a welded contactor. Those call for a line voltage monitor or a compressor protection module, which is a different part on different terminals.