Generac Power Systems 16 kW NG User Manual

OPERATIONAL TESTS

AND ADJUSTMENTS

sEctioN 5.1

sYstEm fuNctioNal tEsts

Part 5

Page 149

DANGER

tHE traNsfEr sWitcH is NoW ElEctri-

callY “Hot”, coNtact WitH “Hot” Parts
Will rEsult iN EXtrEmElY HaZarDous
aND PossiBlY fatal ElEctrical sHocK.
ProcEED WitH cautioN.

5. Use an accurate AC voltmeter to check utility power

source voltage across transfer switch Terminals N1 and

N2. Nominal line-to-line voltage should be 240 volts AC.

6. Check utility power source voltage across Terminals N1

and the transfer switch neutral lug; then across Terminal

N2 and neutral. Nominal line-to-neutral voltage should

be 120 volts AC.

7. When certain that utility supply voltage is compatible

with transfer switch and load circuit ratings, turn off the

utility power supply to the transfer switch.

8. On the generator panel, set the AUTO-OFF-MANUAL

switch to MANUAL. The engine should crank and start.

9. Let the engine warm up for about five minutes to allow

internal temperatures to stabilize. Then, set the generator

main circuit breaker to its “ON” (or closed) position.

DANGER

ProcEED WitH cautioN! GENErator

PoWEr VoltaGE is NoW suPPliED to
tHE traNsfEr sWitcH. coNtact WitH
liVE traNsfEr sWitcH Parts Will
rEsult iN DaNGErous aND PossiBlY
fatal ElEctrical sHocK.

10. Connect an accurate AC voltmeter and a frequency

meter across transfer switch Terminal Lugs E1 and E2.

Voltage should be 242-252 volts; frequency should read

about 61-63 Hertz (7/8 kW units) and about 60 Hertz on

10-20 kW units.

11. Connect the AC voltmeter test leads across Terminal

Lug E1 and neutral; then across E2 and neutral. In both

cases, voltage reading should be 121-126 volts AC.

12. Set the generator main circuit breaker to its OFF (or open)

position. Let the engine run at no-load for a few minutes to

stabilize internal engine generator temperatures.

13. Set the generator AUTO-OFF-MANUAL switch to OFF.

The engine should shut down.

note: it is important that you do not proceed until
you are certain that generator ac voltage and fre-
quency are correct and within the stated limits.

Generally,  if  both  ac  frequency  and  voltage  are
high  or  low,  the  engine  governor  requires  adjust-
ment.  if  frequency  is  correct,  but  voltage  is  high
or  low,  the  generator  voltage  regulator  requires
adjustment.

Generator teStS under load

To test the generator set with electrical loads applied,
proceed as follows:

1. Set generator main circuit breaker to its OFF (or

open) position.

2. Turn OFF all loads connected to the Transfer Switch

Terminals T1 and T2.

3. Set the generator AUTO-OFF-MANUAL switch to OFF.
4. Turn off the utility power supply to the transfer switch,

using the means provided (such as a utility main line

circuit breaker).

Do Not attEmPt maNual traNsfEr

sWitcH oPEratioN uNtil all PoWEr
VoltaGE suPPliEs to tHE traNsfEr
sWitcH HaVE BEEN PositiVElY turNED
off. failurE to turN off all PoWEr
VoltaGE suPPliEs Will rEsult iN
EXtrEmElY HaZarDous aND PossiBlY
fatal ElEctrical sHocK.

5. Manually set the transfer switch to the STANDBY posi-

tion, i.e., load terminals connected to the generator

E1/E2 terminals. The transfer switch operating lever

should be down.

6. Set the generator AUTO-OFF-MANUAL switch to

MANUAL. The engine should crank and start immediately.

7. Let the engine stabilize and warm up for a few minutes.
8. Set the generator main circuit breaker to its ON (or

closed) position. Loads are now powered by the standby

generator.

9. Turn ON electrical loads connected to transfer switch T1

and T2. Apply an electrical load equal to the full rated

wattage/amperage capacity of the installed generator.

10. Connect an accurate AC voltmeter and a frequency

meter across Terminal Lugs E1 and E2.

a. 7/8kW voltage should be greater than 230 volts

and frequency should be greater than 58 Hz.

b. 10-20 kW voltage should be greater than 240

volts and frequency should be

60 Hz.