Product Manual

TP-6946 3/1644 Section 5 Functional Tests
5.5 Voltage Check
The voltage, frequency, and phasing of the transfer
switch and the power sources must be the same to avoid
damage to loads and the transfer switch. Compare the
voltage and frequency ratings of the utility source,
transfer switch, and generator set, and verify that the
ratings are all the same.
Use the voltage check procedure explained in this
section to verify that the voltages and phasing of a ll
power sources are compatible with the transfer switch
before connecting the power switching device and
controller wire harnesses together.
Follow the instructions provided with the generator set
to prepare the generator set for operation.
Read and understand all instructions on installation
drawings and labels on the switch. Note any optional
accessories that have been furnished with the switch
and review their operation.
Note: Source N is the source connected to the normal
side of the contactor. Source E is the source
connected to the emergency side of the
contactor. Verify that the source leads are
connected to the correct lugs before proceeding.
The voltage check procedure requires the following
equipment:
D A digital voltmeter (DVM) with electrically insulated
probes capable of measuring the rated voltage and
frequency
D A phase rotation meter
Hazardous voltage.
Backfeed to the utility system can
cause severe injury, death, or
property damage.
Before energizing the transfer switch,
verify that both the normal and
emergency contacts are not left in the
closed position.
WARNING
Hazardous voltage.
Will cause severe injury or death.
Only authorized personnel should
open the enclosure.
DANGER
Testing live electrical circuits. Hazardous voltage or
current can cause severe injury or death. Have trained and
qualified personnel take diagnostic measurements of live
circuits. Use adequately rated test equipment with electrically
insulated probes and follow the instructions of the test
equipment manufacturer when performing voltage tests.
Observe the following precautions when performing voltage
tests: (1) Remove all jewelry. (2) Stand on a dry, approved
electrically insulated mat. (3) Do not touch the enclosure or
components inside the enclosure. (4) Be prepared for the
system to operate automatically.
(600 volts and under)
Voltage Check Procedure
1. Ensure that all downstream loads are switched off.
2. If the source being measured is a generator set,
start the generator set by moving the master switch
to RUN.
3. Use a voltmeter to check the source
phase-to-phase and phase-to-neutral (if
applicable) terminal voltages and frequency.
a. If Source N is the utility and the measured input
does not match the voltage and frequency
shown on the transfer switch nameplate,
STOP! Do not proceed further in installation
because the transfer switch is not designed for
the application. See Section 2.5 for instructions
to correct the input voltage transformer
connections and contact your distributor/dealer
to order the correct nameplate.
b. If the source is a generator set and the
generator set output voltage and frequency do
not match the nominal system voltage and
frequency shown on the transfer switch
nameplate, follow the manufacturer’s