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MODEL 20VB
TIME MARK is a division of
2.30"
2.70"
3.18"
1.78"
.20" x .31" SLOT
2 PLACES
1.19"
2.20"
3-Phase Monitor
with Adjustable Trip & Restart Delays
⚫ Monitors for Phase Loss, Phase Reversal,
Over/Under Voltage and Voltage Unbalance
⚫ Universal Voltage Range 190-480VAC, 50/60Hz
⚫ Adjustable Trip and Restart Delays
⚫ DIN Rail or Surface Mount
⚫ UL Recognized in the U.S. and Canada
DESCRIPTION
The Model 20VB is a microcontroller-based universal 3phase voltage band monitor for protecting 3-phase
motors of any size from abnormal power conditions. The
Model 20VB can detect under voltage, over voltage,
voltage unbalance, reverse phase, and single-phasing
even when regenerated voltage is present. Status of the
3-phase system is indicated by LEDs.
Relay operation is fail-safe, i.e. the SPDT output
contacts drop out when a fault condition or loss of power
occurs. Under and over voltage trip points are both
adjustable. The under voltage adjustment has two
scales, 185-240VAC and 370-480VAC. The over voltage
adjustment also has two scales, 208-264VAC and 416528VAC. The Model 20VB will auto-range to the
appropriate scale. A trip delay adjustment for preventing
nuisance tripping during power fluctuations and a restart
delay adjustment for preventing short cycling in
compressor applications have also been provided.
Voltage unbalance trip point is fixed at 6%.
The Model 20VB does not require a neutral connection
and can be used on either Wye or Delta systems.
Operating power for the Model 20VB is drawn from
phases A and B.
DIMENSIONS
SPECIFICATIONS
Model 20VB
Operating Voltage 190-480 VAC
Frequency 50/60Hz
Type of Measurement RMS
Auto Ranges Yes
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
Reset Automatic
Output Contacts SPDT 10A at 240VAC resistive
Power Consumption 3W
Operating Temp - 20º to +140º F
Humidity Tolerance 0-97% w/o condensation
Terminal Torque 3.5 in. lbs. maximum
Wire Type Stranded or solid 14-26 AWG, 1/terminal
Enclosure NORYL plastic
Mounting DIN Rail or Surface Mount
Weight 11 oz.
Low Current Options Models ordered with suffix “/SG”
Agency Approval UL Recognized (U.S. and Canada)
185-480VAC
Trip setting +3%
208-528VAC
Trip setting –3%
(conforms to NEMA)
6%, Fixed
5% Fixed
1-30 sec., adjustable
1 sec., fixed
1 sec., fixed
have silver with gold flash contacts
(For use in a Pollution Degree 2 Environment)
11440 Ea s t P in e St re et
Tul s a , Okl a h o ma 7 4 116
02/2019
© 2019 TIME MARK CORPORATION
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MODEL 20VB
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 20VB.
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 Model 20VB in a suitable enclosure either to
the back panel of the enclosure using two #6 x 9/16"
screws or to a DIN rail (Mounting screws not included).
Connect terminals A, B, and C to the line side of the
motor starter. Connect the output relay to the control
circuit.
MODEL 20VB
OPERATION (Cont’d)
The status of the 3-phase system is indicated by the red
and green LEDs as follows:
TROUBLESHOOTING
Should the Model 20VB 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 should 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).
OPERATION
Set the OVER and UNDER voltage adjustments to the
trip points required for the application. Set the
RESTART and TRIP delay adjustments as required for
the application.
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.
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 Ea s t P in e St re et
Tul s a , Okl a h o ma 7 4 116
© 2019 TIME MARK CORPORATION
02/2019
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