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Idiomas disponibles
Idiomas disponibles
Bearing type
Alternator
E1S10
6305-DDU-C3
E1S11
6207-2Z-C3
E1S13
6208-2Z-C3
SLIP-RINGS, BRUSH HOLDER AND BRUSHES
Slip-ring, brush holder-assembly and brushes are designed to guarantee a safe and long service. Therefore, when using the
alternator, no special servicing is needed for at least 2000 working hours for the 2 pole-alternators and 4000 hours for the 4
pole alternators.
In case you notice an unusual working, a sudden disexcitation of the alternator and an irregular electric current supply, it is
necessary to carry out the following simple operations:
1) Check if the slip ring, brush-holder assembly and brushes are clean and if they are correctly positioned.
2) Verify that brushes rest within the surface of the slip ring.
3) Check brushes wear and eventually replace them if worn.
RECTIFYING DIODE BRIDGE (Figure 8)
We normally use rectifying diodes designed for 25A - 800V.
Rectifying diode bridge inspection
Testing every single diode of the rectifying bridge can be carried out either with an ohmmeter or with a battery and a
bulb, as described here below.
A diode works properly when:
-
the resistance across the diode, measured with an ohmmeter, is very low in the forward direction and very high in the
reverse.
-
with a battery and a suitable bulb, the bulb lights up only in one of the two connections in Figure 9: A=Lamp On,
B=Lamp Off.
Note for disassembling: Before removing the rotor from the frame it is necessary to remove the brush-holder as-
sembly.
Drive end
Non drive end
6204-2Z-C3
6205-2Z-C3
6305-DDU-C3
FAULT
CAUSE
1) Insufficient residual voltage
2) Connection broken
3) Faulty 3-phase bridge rectifier
Alternator does not excite
4) Insufficient speed
5) Windings fault
6) Poor contact with the brushes
1) Engine speed low
2) Poor brushes contact
Low voltage with no-load
3) Winding fault
4) Faulty 3-phase bridge rectifier
1) Low speed with load
2) Faulty compound
Correct voltage with no load
3) Faulty rotor winding
but too low voltage on load
4) Load is too high
1) Load with capacitors
Correct voltage with no-load
2) Faulty compound
but too high voltage on load
3) Wrong connection between phases
1) Rotating mass too small
Unstable voltage
2) Uneven speed
3) Loose contact on slip ring
1) Bad coupling
Noisy working
2) Short circuit in some windings
3) Faulty bearing
- 11 -
ACTION
1) Excite the rotor Restore residual
magnetism using an external battery,
applying for a few seconds the
appropriate excitation voltage to the
alternator, directly on the (+) and (-)
terminals of the 3-ph bridge rectifier
2) Repair or renew the connection
3) Replace three-phase diode bridge
4) Adjust speed regulator
5) Check winding resistance and replace
damaged part
6) Clean and check the slip rings
1) Reset speed for drive engine
2) Check, clean or replace brushes
3) Check resistance and replace
damaged part
4) Replace 3-phase bridge rectifier
1) Adjust governor control to nominal
speed
2) Check the compound and eventually
replace it
3) Check rotor winding resistance and
replace the rotor if faulty
4) Reduce the load
1) Reduce capacitive load
2) Check and eventually replace the
compound
3) Check and correct the connection
between phases
1) Increase the drive engine flywheel
2) Check and repair governor control
3) Check and clean the slip-ring and
the brushes
1) Check and/or correct coupling
2) Check windings and/or loads
3) Replace faulty bearing
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