355 Series - 3-Phase Voltage/Phase Monitor

Littelfuse Voltage Monitoring Relays
The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others.

The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions.

The 355-200 is equipped with a heavy-duty 10A general purpose SPDT relay. The 355-400 and 355-600 are equipped with a 470VA @ 600VAC pilot duty SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.

Access specifications, certifications, check availability and order parts below

Catalog #Input
Voltage (V)
Output
Form
Termination TypeMounting MethodDimensionsWeight (lbs/g)Compare
355200190 to 240VACSPDTTorque: 7in-lbs; Wire Size: 12-18AWG#8 screws2.93 in H x 5.27 in W x 2.95 in D (74.4 x 133.9 x 74.9 mm)0.94 lb. (15.0 oz. 426.4 g)
355400380 to 480VACSPDTTorque: 7in-lbs; Wire Size: 12-18AWG#8 screws2.93 in H x 5.27 in W x 2.95 in D (74.4 x 133.9 x 74.9 mm)0.94 lb. (15.0 oz. 426.4 g)
3554005380 to 480VACDPDTTorque: 7in-lbs; Wire Size: 12-18AWG#8 screws2.93 in H x 5.27 in W x 2.95 in D (74.4 x 133.9 x 74.9 mm)0.94 lb. (15.0 oz. 426.4 g)
355600475 to 600VACSPDTTorque: 7in-lbs; Wire Size: 12-18AWG#8 screws2.93 in H x 5.27 in W x 2.95 in D (74.4 x 133.9 x 74.9 mm)0.94 lb. (15.0 oz. 426.4 g)