Generac 86640 - Manual (Page 21)

Section 1.6- TROUBLESHOOTING TEST PROCEDURES
Introduction
The following numbered tests may be performed in con­
junction with identically numbered tests in the "TROUBLE­
SHOOTING FLOW CHART (Section 1.5). The "FLOW
CHART* has been carefully planned to prevent guesswork
and to locate most common generator problems.
NOTE: Quite often the cause of a problem can be deter­
mined by completing a close visual Inspection of the
generator. See "VISUAL INSPECTION" on Page 1.4-2.
Test 1> Check No-Load Voltage and Fre­
quency
DISCUSSION:
When a generator problem occurs, the first step Is to
identify the problem. This can usually be accomplished
quickly by checking the no-load AC ouÿut voltage and fre­
quency. Once the exact problem has been identified, the
cause of the problem can usually be isolated by continuing
orderly tests as shown in the "TROUBLESHOOTING FLOW
CHART".
NOTE: You will have to determine whether the AC leads
have been connected for single voltage output only (120
volts, 60 Hertz o r i l o volts, SO Hertz); or for dual voltage
output (120/240 volts, 60 Hertz or 110/220 volts, 50 Hertz).
See "STATOR AC POWER CONNECTION SYSTEMS" on
Page 1.1-5.
PROCEDURE:
1. Connect an AC voltmeter and AC frequency meter across
the generator’s AC output leads. Open main circuit breaker.
a. If connected for single voltage AC output, connect the
meters across leads T1 and 12.
b. If connected for dual voltage output, connect meters
across leads T1 and 12 or 12 and T3 for a 120 volts, 60
Hertz (or 110 volts, 50 hertz) reading. For a 240 volts, 60
Hertz (or 220 volts, 50 hertz) reading, connect meter test
leads across generator leads T1 andT3.
2. Start the generator engine, let It stabilize and wami up.
3. Read the AC output voltage and frequency. Readings
should be as follows:
a. For units rated 120/240 volts, 60 hertz; readings should
be 121 -126 volts at 61 -63 Hertz; or 242-252 volts at 61 -63
Hertz.
b. For units rated 110/220 volts, 50 hertz; readings should
be 111 -113 volts at 51 -53 Hertz; or 222-226 volts at 51 -53
Hertz.
RESULTS:
1. If the no-load voltage and frequency are good, go to Test
2
.
2. If no-load voltage and frequency are both high or low, go
to Test 5.
3. If frequency reads good but voltage Is low, go to Test 6.
4. If voltage and frequency read "zero", go to Test 1.0.
Test 2- Check Load Voltage and Fre­
quency
DISCUSSION:
Generator problems are sometimes caused by exceed­
ing the wattage/amperage capacity of the unit. What appears
to be a generator problem may, in fact, be caused by an
engine that has lost power. The following facts apply:
D
Quite often, the maximum wattage that can be supplied
by a generator Is limited by available engine power.
When connected loads exceed a critical point, engine
speed will droop. With a reduction in engine speed will
come a voltage and frequency loss.
O It is possible that an engine can lose power to the extent
that even normal rated generator output power can be
achieved. Engine speed, frequency and voltage can then
droop before a unit's rated maximum capacity has been
reached.
PROCEDURE:
If no-load AC output voltage and frequency were within
limits, but operational problems occur when electrical loads
are applied, check the output voltage and frequency under
load as follows:
1. Connect an AC voltmeter and frequency meter across the
generator’s AC output leads. Close the main circuit breaker.
2. Start the generator, let it stabilize and warm up.
3. Apply an electrical load to the generator equal to its rated
maximum wattage/amperage capacity.
4. Read the voltage and frequency.
a. Units rated 120/240 volts, 60 Hertz: Readings should
be at least 116 volts and 58 Hertz (or higher).
b. Units rated 110/220 Volts, 50 Hertz: Readings should
be at least 107 volts, 48 Hertz (or greater).
RESULTS:
1. If load voltage and frequency are below limits, go to Test
3.
2. If voltage and frequency are good, discontinue tests.
Test 3- Check Load Watts and Amperes
DISCUSSION:
If the unit's AC output frequency and voltage drop below
limits when electrical loading is applied, it is possible that the
rated capacity of the generator has been exceeded.
PROCEDURE:
Add up wattage ratings of all electrical loads applied to
the generator at one time. This total should not be greater
than the unit’s rated maximum wattage capacity. If desired, a
clamp-on ammeter may be used to measure load current. The
unit’s rated maximum amperage capacity should not be ex­
ceeded.
Page 1.6-1