Voltage Checks - Generac Power Systems GTS "W" Owner's Manual

3.3

VOLTAGE CHECKS

DANGER
Disconnect all loads from the transfer switch
!
until all voltage checks and phase rotation checks
have been completed to prevent possible injury
to personnel and, or damage to equipment.
For safety, set the maintenance disconnect switch
!
(inside transfer switch enclosure) to its manual
position before proceeding with voltage checks.
Before proceeding, check the transfer switch
!
data PLATE for switch rated voltage. Make sure
the data plate voltage is compatible with NOR-
MAL and STANDBY power source voltages.
Proceed with caution. Do not touch electrically hot
!
terminals, wires, etc. During the voltage checks,
the transfer switch is electrically energized.
Perform voltage checks as follows:
1. Inside the transfer switch enclosure, set the
Maintenance Disconnect switch to MANUAL.
2. If generator is so equipped, set the Manual-Off-Auto
switch to OFF .
3. On the switch enclosure door, set SYSTEM TEST
switch to AUTOMATIC MODE position.
4. Check that the word "ON" is visible in Window "A",
the word "OFF" in Window "B".
OPERATION for location of "A" and "B" windows.
IMPORTANT: DO NOT PROCEED UNTIL STEPS 1,
2, 3, AND 4 HAVE BEEN COMPLETED.
Before proceeding to voltage checks, manually
!
connect the load to NORMAL power supply.
window "A" must indicate ON, Window "B"
must indicate OFF before proceeding.
5. Turn ON the NORMAL (Utility) power supply to the
transfer switch, with whatever means provided
(such as the main line circuit breaker).
DANGER
The transfer switch is now electrically hot.
!
Proceed with caution.
6. With UTILITY voltage available to the transfer
switch, check that the SWITCH - POSITION UTILI-
TY LED on the enclosure door is ON. If the SWITCH
- POSITION UTILITY LED is OFF , turn off the utili-
ty power supply to the transfer switch by whatever
means provided (such as the main line circuit
breaker), then proceed back to Step 1 of "VOLTAGE
CHECKS".
7. Inside the transfer switch enclosure door, locate the
Utility Voltage Sensor Circuit Board. The UTILITY
ON light (LED) should be ON.
8 Generac ® Power Systems, Inc.
Section 3 — Operation
Generac GTS "W" Type Transfer Switch
See MANUAL
8. With an accurate AC voltmeter, check the phase-to-
phase (line-to-line) and phase-to-neutral (line-to-
neutral) voltages present at transfer mechanism ter-
minals N1, N2, N3 and neutral. SUPPLIED VOLT-
AGES MUST BE FULLY COMPATIBLE WITH
TRANSFER SWITCH RATED VOLTAGE.
DANGER
Ensure that the phase rotation of NORMAL
!
(Utility) power lines and transfer switch load
power lines are compatible.
9. Refer to the standby generator instruction manual.
Make sure the generator engine has been properly
serviced and prepared for use, as outlined in that
manual. Then start the generator engine manually.
Let the engine stabilize and warm up for a few min-
utes.
10. Turn ON the STANDBY (GENERATOR) power sup-
ply to the transfer switch by whatever means pro-
vided (such as the main line circuit breaker).
11. With the generator running, check that the STAND-
BY - OPERATING LED on the switch enclosure door
is ON.
12. With an accurate AC voltmeter, check phase-to
phase (line-to-line) and phase-to neutral (line-to
neutral) voltages present at transfer mechanism ter-
minals E1, E2 and E3. Also check AC frequency at
those terminals. If frequency is incorrect, the engine
governor may require adjustment. Generator AC
output voltage and frequency must be compatible
with transfer switch rated voltage and frequency.
DANGER
Ensure that the phase rotation of STANDBY
!
(GENERATOR) power lines and transfer switch
NORMAL (UTILITY) and load power lines are
compatible.
13. If supplied voltage or frequency is incorrect, refer to
standby generator Owner's Manual. If AC frequency
is incorrect, adjust engine governed speed. If volt-
age is incorrect, adjust generator's voltage regulator
or correct the problem.
14. When supplied voltage and frequency is correct,
shut down the engine manually.
DANGER
Supplied voltages from both NORMAL (Utility)
!
and STANDBY (Generator) power sources must
be compatible with transfer switch rated volt-
age before proceeding.
15. Connect the transfer switch load to the transfer
switch when "voltage checks" section has been com-
pleted. Connect the load to the transfer switch by
whatever means provided [such as circuit break-
er(s)], then proceed with the "ELECTRICAL OPER-
ATION" section.