Time Mark 21 Data Sheet

MODEL 21

TIME MARK is a division of

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 available with optional gold

flashed silver contacts for low current applications.

TYPICAL APPLICATION

SPECIFICATIONS

Auto Reset Models
Manual Reset Models*

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

Over Voltage

Trip
Reset

Voltage Unbalance

Trip
Reset

Trip Delay Time

Over, Under, & Unbalanced
Single-Phasing Faults

Unbalance > 15%
Restart Delay 1-500 sec., adjustable
Manual Reset Input 5V open circuit/500µA short circuit

Output Contacts SPDT 10A at 240VAC resistive
Operating Temp - 20º to +140º F
Humidity Tolerance 0-97% w/o condensation
Enclosure Noryl plastic
Mounting
Weight 9.5 oz.
Low Current Options Models ordered with suffix “/SG”

Agency Approval

* External N.O. momentary pushbutton required for manual reset.
**Order 8-pin socket number 51x120

21

21M

Trip setting minus 0.7%

8-Pin Socket (**sold separately)

have silver with gold flash contacts

UL Recognized (U.S. and Canada)

(For use in a Polluon Degree 2 Environment)

21-L

21-LM

(% of setpoint)

90% ±1%
93% ±1%

(% of setpoint)

110% ±1%
107% ±1%

(conforms to NEMA)

2-8%, adjustable

1-30 sec., adjustable

1 sec., fixed
1 sec., fixed

21-H

21-HM

DIMENSIONS

11440 East Pi n e S t r e e t

Tulsa, O k l a h o m a 7 4 1 1 6

2/2019

© 2019 TIME MARK CORPORATION

MODEL 21

TIME MARK is a division of

Universal 3-Phase Monitor

READ ALL INSTRUCTIONS BEFORE INSTALLING, OPERATING OR SERVICING THIS DEVICE.

KEEP THIS DATA SHEET FOR FUTURE REFERENCE.

GENERAL SAFETY

POTENTIALLY HAZARDOUS VOLTAGES ARE PRESENT AT THE TERMINALS OF THE MODEL 21.

ALL ELECTRICAL POWER SHOULD BE REMOVED WHEN CONNECTING OR DISCONNECTING WIRING.

THIS DEVICE SHOULD BE INSTALLED AND SERVICED BY QUALIFIED PERSONNEL.

Installation Instructions

OPERATION (cont’d)

IN APPLICATIONS WHERE VOLTAGES IN EXCESS OF

WARNING

300VAC ARE TO BE MONITORED, BE CERTAIN TO USE
THE TIME MARK MODEL 51X120 8-PIN SOCKET, OR AN
EQUIVALENT 600VAC RATED SOCKET.

INSTALLATION

Mount the 8-pin socket in a suitable enclosure. A NEMA-1
rated enclosure, designed for socket-mounted relays is
available from Time Mark Corporation.

Connect 3-phase power to terminals 3, 4, and 5 on the socket.

Connect the load control wiring to the appropriate terminals on
the socket.

When using manual reset versions either connect a N.O.
momentary switch to terminals 6 and 7 for manual reset
operation or jumper terminals 6 and 7 for automatic reset
operation. Refer to wiring diagram for example of typical

application.

NOTE: When installing the Model 21 monitor in areas of high

humidity or contamination, it is recommended that the base area
and all exposed metal parts of the socket be coated liberally with a

good quality silicone grease, such as Dow Corning DC-4 or DC-4X.

Insert the unit into the socket and wipe off excess grease around
the base. This will prevent the entrance of moisture and other

contaminates into the base and socket areas.

PIN DIAGRAM

OPERATION

Set the VOLTAGE adjustment to the nominal operating

voltage. Models 21 and 21M will auto-range to either the 190­240VAC or 380-480VAC scale. Set the UNBALANCE,

RESTART, and TRIP adjustments as required for the
application.

Automatic Reset Versions

The relay contacts will transfer after applying correct voltage
and phase rotation for the length of the restart delay. The
green LED will blink during the restart delay and will then

remain on indicating the relay contacts have transferred.

Manual Reset Versions

When operating in manual reset mode the restart delay is
disabled and the monitor must always be reset manually after
applying power. Both status lights will blink in unison upon
applying power if the monitor was not in the tripped state prior

to a loss of power.

If a fault condition is detected and the monitor trips, the relay

will remain de-energized until the fault condition clears and

the reset switch is pushed. If the monitor remains in the
tripped state when a loss of power occurs, the fault causing

the trip will be displayed on power up.

Automatic and Manual

Reset Versions

The status of the 3-

phase system is
indicated by the red and
green LEDs as shown

in the LED Status chart:

TROUBLESHOOTING

Should the Model 21 Monitor fail to operate properly, check
that all three voltages are present, and are of the correct
voltage level and phase rotation (a Model 108A or 108B
Phase Sequence Detector could be used to verify phase
rotation). Check all fuses and verify that all wiring connections
are correct. If problems persist, contact your local Time Mark

Distributor or the factory for assistance (Monday-Friday, 8
a.m. to 5 p.m. CST)

WARRANTY

This product is warranted to be free from defects in materials
and workmanship, and is covered by our exclusive 5-year
Unconditional Warranty. Should this device fail to operate
for any reason, we will repair it for five years from the date of
manufacture. For complete warranty details, see the Terms
and Conditions of Sales page in the front section of the Time

Mark catalog or contact Time Mark at 1-800-862-2875.

11440 East Pi n e S t r e e t

Tulsa, O k l a h o m a 7 4 1 1 6

2/2019

© 2019 TIME MARK CORPORATION