6 Generac
®
Power Systems, Inc.
PROCEED WITH CAUTION. GENERATOR OUT-
PUT VOLTAGE IS NOW BEING DELIVERED TO
TRANSFER SWITCH TERMINALS. CONTACT
WITH LIVE TERMINALS RESULTS IN EXTREMELY
DANGEROUS AND POSSIBLY FATAL ELECTRI-
CAL SHOCK.
7. With an accurate AC voltmeter and frequency
meter, check the no-load, voltage and frequency.
Single-phase generator supply:
Measure across ATS terminal lugs E1 to E2. Also
check E1 to NEUTRAL and E2 to NEUTRAL.
a. Frequency ......................................60-62 Hertz
b. Terminals E1 to E2 ........................240-246 VAC
c. Terminals E1 to NEUTRAL ............120-123 VAC
d. Terminals E2 to NEUTRAL ............120-123 VAC
8. Set the generator’s main circuit breaker (CB1) to
its OFF or OPEN position.
9. Set the AUTO/OFF/MANUAL switch to the OFF
position to shut down the generator.
NOTE:
Do NOT proceed until generator AC output voltage
and frequency are correct and within stated limits.
If the no-load voltage is correct but no-load fre-
quency is incorrect, the engine governed speed
probably requires adjustment. If no-load frequen-
cy is correct but voltage is not, the voltage regula-
tor may require adjustment.
3.4 GENERATOR TESTS UNDER LOAD
1. Set the generator's main circuit breaker to its
OFF or OPEN position.
2. Manually actuate the transfer switch main con-
tacts to their EMERGENCY (STANDBY) position.
Refer to Manual Operation (Section 3.2).
3. To start the generator, set the AUTO-OFF-
MANUAL switch to MANUAL. When engine starts,
let it stabilize for a few minutes.
4. Turn the generator's main circuit breaker to its
ON or CLOSED position. The generator now pow-
ers all LOAD circuits. Check generator operation
under load as follows:
• Turn ON electrical loads to the full rated
wattage/amperage capacity of the generator.
DO NOT OVERLOAD.
• With maximum rated load applied, check
voltage and frequency across transfer switch
terminals E1 and E2. Voltage should be
greater than 230 volts and frequency should
be greater than 59 Hertz.
• Let the generator run under rated load for at
least 30 minutes. With unit running, listen for
unusual noises, vibration, overheating, etc.,
that might indicate a problem.
5. When checkout under load is complete, set main
circuit breaker of the generator to its OFF or
OPEN position.
6. Let the generator run at no-load for several
minutes. Then, shut down by setting the AUTO-
OFF-MANUAL switch to its OFF position.
7. Move the switch's main contacts back to their
UTILITY position. For example, load connected to
UTILITY power supply. Refer to Manual
Operation (Section 3.2). Handle and operating
lever of transfer switch should be in UP position.
8. Turn on the utility power supply to transfer
switch, using whatever means provided (such as
a utility main line circuit breaker). The utility
power source now powers the loads.
9. Set the generator's AUTO-OFF-MANUAL switch to
its AUTO position. The system is now set for fully
automatic operation.
DANGER
Section 3 — Operation
Generac GTS “HS” Type Transfer Switch