Time Mark 268 Data Sheet

1.95"

MODEL 268

TIME MARK is a division of

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115 VAC

Over/Under

Voltage Monitor

 Both high & low trip point adjustments

 Monitors over and under voltage

 Useful range of 90 to 140VAC

 Automatic reset

DESCRIPTION

The Model 268 Over & Under Voltage Monitor is
designed to insure that the monitored operating voltage
remains within a 120VAC band. This device uses a
dual op-amp comparator circuit to achieve stable and
repeatable trip setpoints.

The output relay is energized only when the voltage
being monitored remains between the upper and lower
setpoints. Voltages above or below the setpoints will de

-energize the relay, and illuminate the appropriate
indicator LED.

The Model 268 Over & Under Voltage Monitor is
designed for continuous duty operation.

DIMENSIONS

SPECIFICATIONS

Model 268

Setpoint stability

Adjustment range

Response time 50ms

Line frequency 45 - 420Hz

Transient protection 2500V for 10ms

Contacts SPDT

Contact rating 10A at 240VAC resistive

Operating temperature - 20º to +130º F

Humidity tolerance 0-97% without condensation

Enclosure material ABS plastic

Mounting 8-pin socket (*order separately)

Weight 4 oz.

Fixed conditions: 0.1% max
Over temp range: 1.2% max

Over voltage: 120 -140VAC
Under voltage: 90 -110VAC

*order 8-pin socket number 51X120

PIN DRAWING

Sales [phone]

Main [phone]

Shown De-Energized

11/2011

© 2011 TIME MARK CORPORATION

MODEL 268

TIME MARK is a division of

Over/Under Voltage 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 268.

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

THIS DEVICE SHOULD BE INSTALLED AND SERVICED BY QUALIFIED PERSONNEL.

Installation Instructions

INSTALLATION

The Model 268 Over and Under Voltage Monitor is a voltage
sensing relay. The relay requires an 8-pin mounting socket, such as

Time Mark’s Model 51X120. The base connecting diagram on the
unit shows the contacts in the ‘power off‘ condition. The markings on

the unit show the proper voltage and adjustment range of the device
to be installed.

Connect the wiring to socket, as required (see the Typical
Application diagram).

ADJUSTMENT PROCEDURE

A variable voltage source and a digital voltmeter provide the most
accurate means of calibrating the trip point setting. However, for AC
line voltages, you can often obtain a satisfactory calibration by using
only the AC line voltage.

Rotate the UNDER VOLTAGE adjustment pot clockwise, until the
relay trips, and the UNDER VOLTAGE LED indicator is lit.

Then, rotate the adjustment pot counter-clockwise slowly, until the
relay resets. The UNDER VOLTAGE LED should be off.

Rotate the OVER VOLTAGE adjustment pot counter-clock-wise,
until the relay trips, and the OVER VOLTAGE LED indicator is lit.

Then, rotate the adjustment pot clockwise slowly, until the relay
resets. The OVER VOLTAGE LED should now be off.

These calibrations will be correct in most applications. If
nuisance tripping occurs, turn the adjustments for a slightly
wider voltage band.

NOTE: When installing the Model 268 Voltage 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.

TROUBLESHOOTING

Should the Model 268 Over and Under Voltage Monitor fail to
operate properly, check all wiring connections. Verify that the
correct voltage is present, and check all fuses. Should problems
persist, contact your local Time Mark distributor, or the factory at
800-862-2875 (Monday-Friday; 8 a.m. to 5 p.m. CST), for further
assistance.

WARRANTY

This product is warranted to be free from defects in materials and
workmanship, and is covered by our exclusive 5-year Uncondi-
tional 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.

TYPICAL APPLICATION

Sales [phone]

Main [phone]

Shows No Power

Applied

11/2011

© 2011 TIME MARK CORPORATION