Description
THREE PHASE VOLTAGE MONITOR
The 355 series is a three-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance, and
multiple diagnostic lights. It is ideal for heavy-duty applications that need both protection and simple user-friendly
diagnostics. Suitable applications include pump panels, commercial HVAC, oil rigs, and many more. The 355 series uses
microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. It can
protect motors from damage caused by single-phasing, high- and low-voltage, phase reversal, and voltage unbalance.
These relays have four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase, and
normal conditions. The adjustable trip and restart settings prevent nuisance tripping due to rapidly fluctuating power line
conditions and allow staggered start-up of multiple motors after a fault to prevent a low-voltage condition.
Series 355 models include the 355-200, which is equipped with a heavy-duty 10 A general purpose SPDT relay. The 355-
400 and 355-600 models are equipped with a 470 VA @ 600 V ac pilot duty SPDT relay. A high-voltage (600 V) DPDT relay
output option is available with the 400 V model.
Applications
• Pump panels
• Commercial HVAC
• Oil rigs
• Heavy-duty applications that need both protection and simple user-friendly diagnostics
