Yamaha EF4500iSE - Inverter Generator, Theory & Diagnostics Manual

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Yamaha Generator Theory & Diagnostics Guide
Then test for a short to ground. Connect one meter
lead to one end of the rotor winding and the other
end to the core of the rotor. There should be an open
circuit on a good rotor.
One of these tests should reveal the faulty compo-
nent.
THEORY FOR AVR TYPE GENERATORS
As mentioned earlier, the generation of electricity
begins with a small permanent magnet inside the
Exciter Field Coil, as opposed to residual magnetism
in the rotor, on non-AVR types.
When the engine begins to turn, a small amount of
AC voltage is generated by the Exciter Armature
Coil, one of the three sections that make up the
rotor, spinning inside of the Exciter Field Coil’s per-
manent magnet.
This AC voltage is then fully rectified into DC voltage
by four diodes mounted on the rotor. These diodes
are referred to as Rotor Rectifiers and are the sec-
ond of the three rotor sections.
ROTOR SHORT TO GROUND TEST