How to replace alternator bushes?

From what I have gathered off here, I think my alternator bushes may need renewing. How do I do this? Is it a hard job? I think its an old Lucas A127 or something similar. So would it be cost effective to do , bearing in mind could probably get a replacement/refurbished alternator from a scrap yard etc for not much money. How much are the bushes?

Reply to
T Rodger
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Under a tenner, & they're fairly easy.

Reply to
Duncanwood

Do you mean bushes (i.e. the bearings) or brushes (the carbon things that contact the commutator)? I have reason to suspect you mean the latter.

Rob Graham

Reply to
Rob graham

An alternator does NOT have a commutator, it has slip rings which vastly reduce the amount of brush wear as they are a solid ring and not segmented. Dynamos (as fitted in days of old) on the other hand do have a commutator.

Both generators produce a.c. in the windings. The alternator converts this to d.c. AFTER the slip rings via a full wave bridge rectifier. The dynamo converted this to d.c via the commutator.

Therefore I suspect the OP actually meant BUSHES as he originally stated.

Reply to
Slurp

why would you think that? brushes fail on alternators too. also very few alternators (if any?)have bushes, they have bearings.

mrcheerful

Reply to
mrcheerful

That's almost right. In an automotive alternator, the slip rings feed the field coils, which rotate. The regulator controls the current to the field coils (ie, the strength of the rotating magnet, and thus the power output). The output AC power is generated in the stator (fixed), which is wired directly to the rectifier (converting the AC to DC).

From this point of view, a DC generator is "inside-out". The field coils are fixed, and power is generated in the armature rotating inside. That AC is _mechanically_ rectified by commutator and brushes, as you say. It's not just the roughness of the commutator which causes more brush wear with a generator. It's the much heavier output current (than field-coil current) and the continual sparking as the circuit gets broken on the individual segments.

Typically, slip ring brushes will wear out long before the bearings do.

John

Reply to
John Henderson

Although you're quite right in what you say (my sloppy usage) I still think he may have meant brushes.

Rob Graham

Reply to
Rob graham

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