3-Phase Monitor with Adjustable Trip & Restart Delays

 

• Monitors for Phase Loss, Phase Reversal, Over/Under Voltage and Voltage Unbalance
• Three Voltage Options
• LED Status Indicators
• 8-Pin Socket Mount
• UL Recognized in the U.S. and Canada

 

Description

The Model 21 is a microcontroller-based universal 3-phase monitor for protecting 3-phase motors from abnormal power conditions. It can detect under voltage, over voltage, voltage unbalance, reverse phase, and single-phasing even when regenerated voltage is present. The Model 21 includes adjustable trip and restart delays to prevent nuisance tripping during power fluctuations and short cycling in compressor applications. The LED status indicators and adjustment pots for Voltage Adjustment, % Unbalance, Restart Delay and Trip Delay are mounted on the front of the unit for easy access.

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

All versions of the Model 21 are UL Recognized (U.S. and Canada) and are available with optional gold flashed silver contacts for low current applications.

 

Specifications

Auto Reset Models Manual Reset Models	21 21M	21-L 21-LM	21-H 21-HM
Operating Voltage	190-480 VAC	95-120 VAC	475-600 VAC
Power Consumption	3.7W at 480V	3.7W at 120V	4.5W at 600V
Auto Ranges	Yes	No
Frequency	50/60Hz
Type of Measurement	RMS
Under Voltage Trip Reset	(% of setpoint) 90% ±1% 93% ±1%
Over Voltage Trip Reset	(% of setpoint) 110% ±1% 107% ±1%
Voltage Unbalance Trip Reset	(conforms to NEMA) 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., adjustable
Manual Reset Input	5V open circuit/500μA short circuit
Output Contacts	SPDT 10A at 240VAC resistive
Operating Temp	- 20° to +140° F
Humidity Tolerance	0-97% w/o condensation
Enclosure	Noryl plastic
Mounting	8-Pin Socket (**sold separately)
Weight	9.5 oz.
Low Current Options	Models ordered with suffix “/SG” have silver with gold flash contacts
Agency Approval	UL Recognized (U.S. and Canada) (For use in a Pollution Degree 2 Environment)

Downloads

Document	File Type	File Size	Download
Model 21 Datasheet	PDF	417 KB

© 2023 Relay Specialties, Inc.
17 Raritan Road, Oakland, NJ 07436 | 800-526-5376
Created By: G.Dezines