Kubota K008-3 Workshop Manual page 381

2) Regulator
The regulator is equipped with rectifying and voltage regulating functions. It converts the alternating current
generated by the AC dynamo to direct current and works for supplying electric current when battery is
charged and light is loaded. When the battery voltage exceeds 14.5 V, the regulator prevents overcurrent.
Besides, when the AC dynamo does not generate alternating current, the charge lamp lights up to so inform
the operator.
Principle of electric power generation
When engine is rotat-
ing
When engine is
stopped
Checking to be done when power generation is impossible (Carry out checking, paying attention to
rotating parts.)
Connect the AC tester to the dynamo terminal and check to see whether or not alternating current of about
higher than 20V is generated when the engine is rotated at max. speed. (Photo 1))
When no electricity is
generated
When electricity is
generated
(Photo 1)
The permanent magnets of the dynamo is rotated in the coil by fan belt to generate alternating cur-
rent. Generated alternating current is rectified and regulated for voltage by the regulator and
charged to the battery.
Since the dynamo is not rotated, no electric power is generated.
1. Decrease in magnetic power of dynamo permanent magnets
2. Breakage of dynamo coils
(Connect the tester to the dynamo terminal and check conductivity.) (Photo 1)
1. Damage to regulator (Photo 2)
2. Breakage of wire(s) (Check conductivity.)
3. Poor contact of coupler, wire etc.
This AC dynamo is so designed as to mount a cooling
fan at the shaft end and composed of a rotor and sta-
tor.
The stator has six magneto coils around which the
rotor having (six) permanent magnets rotates to gener-
ate alternating current at the stator coils.
3) Regulated voltage without load
1. Start the engine and gradually raise the rotating
speed.
2. Raise the engine rotating speed gradually while
checking the voltage and check to see if the volt-
age rises higher than the standard value.
3. If the voltage stays lower than the standard value,
replace the dynamo.
Generated voltage without load
Standard value: Higher than AC 20 V
V-S-23
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