Generac Power Systems MC - Manual (Page 41)

TEST 36:- CHECK VOLTAGE
Disconnect customer wiring from
Wires No. T1 and T2 in alternator
connection box. Check a-c voltage
output at Wire No. T1 and junction
of Wires T2. Reading should be ap­
proximately 125 Volts a-c at no-load
and 115-125 Volts a-c under load.
RESULT:- Vol.tage output bad,,
Voltage checks good.
.Continue diagnostic tests
.....Check customer wiring
NOTE
Alternators are factory connected to provide a 120 Volt a-c output
only. Some units may have been reconnected to supply 120/240 Volts
a-c. See Page 1.2-3.
TEST 37;- SENSING TRANSFORMER
A./-Remove 2 wire nuts that connect
wires No. 11 and 22, between Sensing
Transformer and Voltage Regulator.
Disconnect the wires. Set VOM to
”+DC” and to ”Rxl00" scale, then ze­
ro the meter. Connect meter test
probes across wires No, 11 and 22
from the Sensing Transformer. Meter
needle should swing upscale and indi­
cate secondary winding resistance.
See illustration at right.
White Connector Plug
Resistance (± 15%)
Winding Wescoil Coiltran
Primary 785 ohms 969 ohms
Secondary 1886 ohms 1438 ohms
RESULT;- Secondary winding resistance checks good... Go to Paragraph В
Meter needle does not swing upscale....... Replace Transformer
B.)- Unplug the white connector plug from its receptacle on the stator
can. Set VOM to ”-t-DC” and to ”RxlO, 000" scale. Zero the meter. Connect
one meter test probe to white connector plug Pin No. 3. Connect the re­
maining probe to white connector plug Pin No. 5, Meter needle should
swing upscale and indicate PRIMARY winding resistance. See illustration
above right.
2.2-19