Replacement for alternator

[Tintin]

I've got an SEV Marchal A14/35 alternator that i think may have died tonight.

Its on a volvo md1b.

Any suggestions for a replacement from a scrap yard?

 

[VicS]

Worth investigating the problem with the existing alternator although a replacement from a scrappy is likely to be cheaper than a professional overhaul.

Easy enough to check the rectifier. Unlikely to be a problem with windings although easy to check for continuity so if rectifier and field diodes OK that only leaves the regulator.

I think that particular alternator was used in a very small number of Renaults long long ago so chances of finding one are small.

Comes down to finding a small alternator that will physically fit the mountings or that can be made to fit I reckon.

 

[Tintin]

Thx. VicS.

How do i test the rectifier? Ive got plenty of time on my hands today holed up at wisemans reach while this weather blows thru.

Btw i'm enjoying the irony of having this problem within a day of duscussing a new charging system.

 

[MrCramp]

If you decide you need some advice on replacement/refurbishment then these people know what they are talking about and we found them very helpful when needing a solenoid for a Volvo MD2b. They are at Plymouth but do mail order.

http://www.startermotor-alternator.co.uk/

 

[VicS]

Thx. VicS.

How do i test the rectifier? Ive got plenty of time on my hands today holed up at wisemans reach while this weather blows thru.

Btw i'm enjoying the irony of having this problem within a day of duscussing a new charging system.

It is a workshop job, I think, rather than an on board on a rainy day job.

The rectifier has to be removed. It is a long time since I saw one of these in bits but removing the rectifier I think will need serious soldering equipment but if you have a small gas blowtorch it'll be possible
You also need a digital multimeter with a "diode test" range or an analogue meter with ohms ranges. ( ohms ranges on a digital meter may not not work)

Between the positive output connection and each of the AC input connections is a diode. Between the negative ( earth) connection and each of the AC connections is another diode. Making 6 of them. Each diode when tested with the meter should give no reading ( infinite resistance) connected one way but a reading ( Probably 600 ish on a diode test but a low resistance on an analogue Ohms range) when connected the other way.

BUt there may be three more diodes, the field diodes connected between the AC output wires and the field output connection ( terminal 61). These should test in the same way.

BUT some alternators do not have the field diodes, ( this may be one), they have a blocking diode in the positive output and the field current is taken from the positive connection of the rectifier diodes. Test that as well in the same way

Diagrams below illustrate the two possible types.

If I have mis-identified the alternator there could be brushes and slip rings to check but I am pretty sure this 35A SEV Marechal one does not have brushes.

.

 

[Tintin]

Thanks VicS. Just what the doctor ordered. I posted a new thread as this one was drifting

So i stealed myself for getting dirty, cut my hand moving the engine cover, banged my head digging out the socket set, got all the tools out, drew a picture so i would know hiw to put it all back together, wiggled the wires, and it works again. Another wiggle stops it so will re wiggle, charge the batteries, listen to the archers, and check and solve when at home port.

Thx again for the help - isnt the mibile interweb great.

 

[chewi]

I've got an SEV Marchal A14/35 alternator that i think may have died tonight.

Its on a volvo md1b.

Any suggestions for a replacement from a scrap yard?

The Marchal 14a/35 is brushless, so only the electonics are likely to be done in.

Last month I had mine serviced that included replacing All its electronics for £80 , and all is now well... I'm based in Poole, the guy is AJW electrics 220 Leigh Road Wimborne, Dorset Google for phone no. He knows his alternators.

Maybe theres someone more local, but it's prob worth doing.