Time Mark 252 Data Sheet

MODEL 252

L1

L2

L3

M

M

M

M

MOTOR

O/L's

Start

Remote
Indicator
Lamp

Stop

Control

Voltage

Model

252

M

3 4

5

6 1

2

8

7

TIME MARK is a division of

3-Phase Monitor

 Detects Phase Loss, Low Voltage
and Phase Reversal

 50Hz and 60Hz versions

 Automatic Reset

DESCRIPTION

The Model 252 3-Phase Monitor continuously monitors

3-phase power lines for abnormal conditions. When

properly adjusted, the Model 252 will detect phase loss
on a loaded motor even when regenerated voltage is
present.

This device consists of a solid-state voltage and phase­angle sensing circuit, driving an electromechanical relay
with one SPDT and one SPST contact. When correct
voltage and phase rotation are applied, the internal
relay will energize. A fault condition will de-energize the
relay. When the fault is corrected the Model 252 will
automatically reset.

The Model 252 does not require a neutral connection
and can be used with WYE or DELTA configured
systems. Four versions cover 120V, 208/240V and
480V, 60Hz, and 380V, 50Hz. Adjustment ranges are
sufficiently wide to allow for proper adjustment to
existing conditions. Two LED indicators are provided to
aid in adjustment and system troubleshooting.

TYPICAL APPLICATION

SPECIFICATIONS

Model B252B 252B A252B EX252B

Nominal AC Voltage 120VAC 208/240VAC 480VAC 380VAC

Adjustment Range 85-120VAC 160-240VAC 380-480VAC 300-380VAC

Frequency 60Hz 50Hz

Power Consumption

Transient Protection 2500V for 10ms

Repeat Accuracy

Response Time

Reset Time

Reset Type Automatic

Dead Band 2%

Output Contacts 1 - SPDT 1 - SPST (N.O.)

Contact Rating 5A at 115VAC resistive

Expected Relay Life Mech: 10 million operations

Operating Temp - 20º to 131º F

Humidity Tolerance 97% w/o condensation

Enclosure Material ABS plastic

Mounting 8-pin socket (*order separately)

Weight 5 oz.

Agency Approvals UL Recognized (U.S. & Canadian)

0.25W 0.50W 1.5W 1.25W

0.1% of set point (fixed conditions)

0.05 seconds

0.05 seconds

Elec: 100,000 at rated load

*Order 8-pin socket number 51X120

Shows No Power Applied

DIMENSIONS

11/2011

© 2011 TIME MARK CORPORATION

A

B

C

MODEL 252

TIME MARK is a division of

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 252.

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

THIS DEVICE SHOULD BE INSTALLED AND SERVICED BY QUALIFIED PERSONNEL.

Installation Instructions

INSTALLATION

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

Connect the 3-phase power to terminals 3, 4 and 5 on the
socket. Phase rotation may be verified using a Time Mark
Model 108A or 108B Phase Sequence Detector.

Connect the load control wiring to the appropriate terminals on
the socket. The SPST contacts (pins 6 and 7) are electrically
isolated from the SPDT contacts.

For motor control and phase loss alarm applications; use
the SPDT contacts.

For auxiliary indicator applications; use the appropriate
SPST contacts.

Insert the Model 252 into the socket.

Apply power. If the contacts do not transfer, (TRIP indicator­On ), check that all phases are present and of the correct
voltage. If power is correct, rotate the level adjustment counter

-clockwise.

If the contact still does not transfer, remove power and reverse
two of the three phase wires at the socket (phase rotation is
reversed). Re-apply power. The contact should transfer to
provide a signal path between both sets of normally-open
contacts. The green LED (NORMAL) should be lit.

Note: When installing the Model 252 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 contaminants into the base and socket
area.

PIN DIAGRAM

ADJUSTMENT

The following procedure will adjust the Model 252 to trip below
the nominal voltage.

Rotate the level adjustment clockwise, until the relay contact
transfers (TRIP indicator On). Slowly turn the adjustment
counter-clockwise, until the contact resets. This setting will be
correct for most applications.

Should nuisance tripping occur, turn the adjustment slightly
farther counter-clockwise, lowering the trip level. A more
accurate adjustment procedure requires a 3-phase variac,
allowing the voltage to be lowered to a specific voltage. The
Model 252 can then be set to trip at this precise voltage level,
when installed in the motor control circuit. Factory set
versions are also available.

TROUBLESHOOTING

Should the Model 252 fail to operate properly, check that all
three voltages are present and are of the correct level and
phase rotation (a Model 108A or 108B Phase Sequence
Detector may be used to verify phase rotation). Check all
fuses and verify that all wiring connections are correct. Should
problems persist, contact the manufacturer at 800-862-2875.

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.

11/2011

© 2011 TIME MARK CORPORATION