Power Monitoring and Protection

355 Series

Product Bar End
Product Bar End

355 Series

MotorSaver™ Three-Phase Voltage Monitor 355 Series

MotorSaver™ Three-Phase Voltage Monitor


MotorSaver™ 355 Series three phase voltage monitors are designed to protect three phase motors regardless of size. The 355-200 model 3 phase monitor can be used with 190-240 volt AC input voltages. The 355-400 model three phase monitor works with 380-480 volt AC input voltages. Also, the 355-600 model monitors 575-600 volt AC input voltages. This range of voltage monitors meets the needs of most HVAC applications and building automation systems, BAS. The unique microprocessor-based voltage and phase-sensing circuit constantly monitors the three phase voltages to detect harmful power line conditions, including single phasing, low-voltage, phase reversal, voltage unbalance, and high voltage. When a harmful condition is detected, the 355 Series output relays are deactivated after an adjustable trip-delay time period. The output relay reactivates after power line conditions return to an acceptable level for an adjustable restart delay time. The trip and reset delays prevent nuisance tripping due to rapidly fluctuating power line conditions.


(Wholesale customers, log in for your special pricing)

QtyModelDescriptionIn StockList PriceInternet Price
355-200 3PH VOLT MONITOR 190-240V SPDT INFO564.55451.64
355-400 3PH VOLT MONITOR 380-480V SPDT In Stock589.34471.47
355-600 3PH VOLT MONITOR 575-600V SPDT In Stock619.44495.55


No accessories found
  • Protection of three-phase motors from loss of any phase, low-voltage, phase reversal, voltage unbalance, and high voltage
  • Adjustable restart delay
  • Adjustable trip delay
  • Adjustable voltage-unbalance trip point
  • Four diagnostic LEDs show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions
  • UL and ULC listed
  • Single-phase condition detection regardless of regenerated voltages

Supply Voltage:model specific 190-240, 380-480, or 575-600 VAC

Supply Watts:6W maximum

Frequency:50*/60 Hz

 :* 50 Hz will increase all delay times by 20%

Relay Rating SPDT, pilot duty 470 VA @ 600 VAC (400 or 600V range) General-purpose 10A @ 240 VAC (200V range) 1hp @ 240 VAC (200V range):

Transient Protection:2500V for 10 ms

Low Voltage Trip:90% of setpoint (±1%)

Low Voltage Reset:93% of setpoint (±1%)

Reset Delay Time after Fault:Manual or 2-300 seconds

Reset Delay Time after Power Loss:Manual or 2-300 seconds

Trip Delay Time High Voltage:2-30 seconds, adjustable

Trip Delay Time Low Voltage:2-30 seconds, adjustable

Trip Delay Time Phase Fault:0.5 seconds

Trip Delay Time Unbalance:2-30 seconds, adjustable

Voltage Unbalance Reset:Trip setting minus 1%

Voltage Unbalance Trip:2% to 8%, adjustable

Dimensions:2.9"H x 5.25"W x 2.9"D

(7.4 x 13.3 x 7.4 cm):


Weight:1.0 lb (0.45 Kg)

Approvals:UL File #E68520

Warranty 5 years: