Yamaha EF4500iSE Theory & Diagnostics Manual page 38

Yamaha Generator Theory & Diagnostics Guide
If not, continue to the next step.
With the meter set for 200 volts AC and the genera-
tor end cap removed, check for voltage between the
brown and the red wire.
If the voltage is 120, then the problem is in the con-
trol box, such as the AC protector or the receptacle
itself, or with the wiring between the generator and
the control box.
Check all wiring and test the AC protector and the
receptacle for continuity.
If the voltage is below specification, then the prob-
lem is within the generator unit itself.
Start by disconnecting the sub and main coil leads
and set your meter to the specified range to check
their resistance. Measure the sub coils resistance
between the two Green wires.
Next measure the main coils resistance between the
Brown and Red wires.
Even if the stator passes both of these tests, there
are still two important tests to perform before we can
eliminate the stator as the problem.
Those two tests are a "Short to Ground" and
"Shorted Together" test.
To better understand these tests, we need to know
the construction of the two types of coils.
The first type is a single lead coil. This is where an
insulated wire is wrapped around an iron core, with
one end of the wire attached to the core.
A resistance test on this type of coil is taken between
the unattached end of the wire and the core. A short
to ground test does not apply here.
SUB-COIL RESISTANCE TEST
MAIN COIL RESISTANCE TEST
SINGLE LEAD COIL RESISTANCE TEST
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