Replacement Alternator

[Langers]

Could anyone recommend a replacement 70 Amp / 12W alternator? My existing alternator has a HMI part number of 900021-ALS and charges the starter battery.

 

When I google the alternator the following website has the existing alternator listed:

 

http://www.prestolite.com/pgs_products/specs.php?item_detail_id=13070&item=66021126&product=ALTERNATOR

 

Is it still available? Can you replace just the regulator / brushes?

 

I intend to remove the faulty alternator this weekend so any advice gratefully received.

[Sir Nibble]

This is the almost ubiquitous lucas A127 alternator. It is almost infinitely repairable and I have rebuild literally thousands. I would be happy to help you to identify the failed component if you wish.

[eggpie]

^this. Parts for the A127 type are easily available. Although I paid <£50 for an unbranded replacement that's still running perfectly, and then rebuilt the original as a spare. Do you know what's wrong with yours?

[JamesWoolcock]

I've just had a new 120amp alternator from CJF Rotating Auto Electrics of Hednesford, Staffordshire for £62.40! Result I think.

 

mail@cjfrotating.com

Tel: 01543 424717

 

Try them

 

 

James

[Langers]

^this. Parts for the A127 type are easily available. Although I paid <£50 for an unbranded replacement that's still running perfectly, and then rebuilt the original as a spare. Do you know what's wrong with yours?

 

thanks for identifying it as an A127 ... I assume it's just the brushes as I'm not getting any charge from it ... I'm going to remove the unit on Saturday and check the regulator ... hopefully it's just a case of swapping them out with these:

 

http://www.jcrsupplies.co.uk/products/ALTERNATOR_REBUILD_PARTS/ALTERNATOR_BRUSH_SETS/LUCAS_A127_ALTERNATOR_BRUSH_SET_3-9_X_6-9_X_20_REF_ABR5409.html

[MtB]

 

thanks for identifying it as an A127 ... I assume it's just the brushes as I'm not getting any charge from it ... I'm going to remove the unit on Saturday and check the regulator ... hopefully it's just a case of swapping them out with these:

 

http://www.jcrsupplies.co.uk/products/ALTERNATOR_REBUILD_PARTS/ALTERNATOR_BRUSH_SETS/LUCAS_A127_ALTERNATOR_BRUSH_SET_3-9_X_6-9_X_20_REF_ABR5409.html

 

Assumption is the mother of all cock-ups.

 

Check or test and find out for sure whenever fault tracing is involved.

 

 

MtB

[Tony Brooks]

How do you know its not charging? If its the red light on it is unlikely to be the brushes but it could be a short to earth on the warning lamp to alternator lead. Anyway even if it is the brushes how warn are the slip rings?

 

If the red light refuses to come on at any time take the warning lamp connection off the alternator (D+) and touch it to any clean metal on the alternator/engine with the ignition on. If it comes on then I agree probably brushes but you know nothing about the slip rings.

[Langers]

I was first alerted by continuos bleep from the alarm when starting up (plus red light staying on) ... normally goes off with a rev but now stays on. I suspected the alternator and put my voltmeter across it ... no charge as such (just residue from the starter battery) .

 

I have two identical alternators and the one for the domestic batteries is fine ... I'll take it apart tomorrow so will know more then. New brushes may not fix it but as it's such an easy replacement then it's worth a try.

[Sir Nibble]

I'll take it apart tomorrow so will know more then. New brushes may not fix it but as it's such an easy replacement then it's worth a try.

No it's not. Might as well top up the water tank and see if that helps. Did the light remain bright? or did it dim?

[nicknorman]

Might as well top up the water tank and see if that helps.

 

Yes that should do it. A change of boat trim will change the angle of the alternator, the rotor will move along slightly by gravity and it will all start working again!

[b0atman]

Brushes do stick have you given alternator a clunk with a precision calibration device like my mooring pin ?

[magnetman]

Handy to have an alternator which tells you when the water tank is empty. Modern technology is amazing

Coat

 

Beaten to it

[Sir Nibble]

Presuming that as an engine alternator there is no external gear fitted such as a split charge relay then it is likely to be ......

1/ Short to earth on the wl wire

2/ Rectifier demolished by reverse connection

3/ Stator failure

4/ Short to earth on w wire

[ditchcrawler]

Presuming that as an engine alternator there is no external gear fitted such as a split charge relay then it is likely to be ......

1/ Short to earth on the wl wire

2/ Rectifier demolished by reverse connection

3/ Stator failure

4/ Short to earth on w wire

I'll go for the diode.

[Langers]

Swapping the regulator unit made no difference ... the brushes have plenty of life left.

 

Looking at replacements ... http://www.ebay.co.uk/itm/180956029368 ... seems a good match?

 

I'll repair the other and keep as a spare.

 

Thanks for all the advice

[Arthur Brown]

An A127 alternator should be a simple swap at a suitable auto electricians -so they send the wreck for repair. However please have a look for a reason for the failure, -are there any obvious torn or worn wires or connections.

[Tony Brooks]

Wana join me Sir N

[ditchcrawler]

Wana join me Sir N

Can I come to. Why are people so reluctant to find the fault or at least eliminate others.