Model 20/21 3-Phase Monitors with Trip and Restart Delays

Jan. 22, 2018

 

The Model 20 & 21 are microcontroller-based universal 3-phase monitors for protecting 3-phase motors from abnormal power conditions. They can detect under voltage, over voltage, voltage unbalance, reverse phase, and single-phasing even when regenerated voltage is present.  The Model 20 & 21 include adjustable trip and restart delays to prevent nuisance tripping during power fluctuations and short cycling in compressor applications.  Both units have LED status indicators and adjustment pots for Voltage Adjustment, % Unbalance, Restart Delay and Trip Delay.  The Model 20 & 21 are UL Recognized in the U.S. and Canada.

 

Automatic or manual restart versions are available.  The Model 20 & 21 do not require a neutral connection and can be used on either Wye or Delta systems.

Reset*

Auto or Manual

Operating Voltage

190-480 VAC

95-120 VAC

475-600 VAC

Frequency

50/60Hz

Type of Measurement

RMS

Under Voltage

Trip

Reset

 

90% ±1%

93% ±1%

Over Voltage

Trip

Reset

 

110% ±1%

107% ±1%

Voltage Unbalance

Trip

Reset

 

2-8%, adjustable

Trip setting minus 0.7%

Trip Delay Time

Over, Under, & Unbalanced

Single-Phasing Faults

Unbalance > 15%

 

1-30 sec., adjustable

1 sec., fixed

1 sec., fixed

Restart Delay

1-500 sec.

Output Contacts

SPDT   10A at 240VAC

Mounting

DIN Rail/Surface Mount or 8-Pin Socket

Agency Approval

UL Recognized (U.S. and Canada)