Alternator

Bensdexta · Post by **Bensdexta** » Sat Jan 10, 2009 9:04 pm

I'm contemplating fitting an alternator as my dynamo & regulator are fubared. It will be a working tractor, so I feel such an update is allowed (together with a more comfy seat!).

Have any UK folks done this? What is a good alternator to fit? Any snags to watch out for?
Many thanks,
Ben

crofter · Post by **crofter** » Sat Jan 10, 2009 11:27 pm

Hi Ben, the alternator I would fit would be a Lucas LRA type, these were fitted to Mini's and other popular car's, it has a self contained Regulater and minimum Wireing required, it should not be hard to mount on the engine, I used this type on my International B 275, but I left my Super Dexta with a dynamo.
Regards
Ronnie.

Bensdexta · Post by **Bensdexta** » Sun Jan 11, 2009 12:52 am

Ronnie,
Which LRA type did you fit - there seem to be lots of them?
How many wires does it have and what output is it?
Many thanks for your help,
Ben

crofter · Post by **crofter** » Sun Jan 11, 2009 2:38 pm

Hi, sorrie I dont know which Alternator I fitted, when I bought it I exchanged it with a Mini Alternator at a local motor factors, but I do know it's a Lucas reconditioned one. The wireing is very simple, only two wires to the back, a large wire (the feed ) and a small one for the warning light. It is very simple to convert from a Dynamo to an Alternator, wireing wise anyway. If I come across my old Mini manuel I can maybe give you more information about charge rates and sutch, the one I fitted always charged well,
the Interrnational was not the best starter but the alternator always kept the battery charged.

Bensdexta · Post by **Bensdexta** » Sun Jan 11, 2009 3:32 pm

crofter wrote:Hi, sorry I don't know which Alternator I fitted, when I bought it I exchanged it with a Mini Alternator at a local motor factors, but I do know it's a Lucas reconditioned one. The wiring is very simple, only two wires to the back, a large wire (the feed ) and a small one for the warning light. It is very simple to convert from a Dynamo to an Alternator, wiring wise anyway. If I come across my old Mini manual I can maybe give you more information about charge rates and such, the one I fitted always charged well, the International was not the best starter but the alternator always kept the battery charged.

Ronnie,
Did you use a similar scheme to Commander on his Major:

commander wrote:..here is a general wiring diagram for an internal regulated alternator....this one happens to be a Delco ..but most are similar.
(it's labelled 'generator' in the pic, but it's an alternator)

Terminal labelled 1 in the diagram is the field coil and is usually wired to the charge light....and sometimes needs a resistor in parallel to get the alternator to charge at low rpm. (radio shack carries some resistors that work fine ..10 ohm 10 amp ceramics)

Terminal labelled 2 is the voltage sensing feature...on a 'one wire'
hookup it would be jumpered to the output lug (BAT) on the alternator.

Many thanks,
Ben

Tubal Cain · Post by **Tubal Cain** » Sun Jan 11, 2009 3:52 pm

I obtained an alternator from the local scrapyard for £10.00 and fitted it to my Dexta.

Assuming that you do not intend to fit umpteen lamps or other devices to the tractor, then virtually any 12 volt alternator with a self contained regulator can be used. You will have to fabricate a suitable bracket to mount it on the engine and you may require a longer fan belt.

You require a heavy wire from the large terminal on the alternator either to the starter motor or the battery terminal on the solenoid. With a lighter wire from the small terminal to the ignition warning light, a switch should be fitted in this circuit to prevent the battery draining through the alternator when the engine is not running.

If you fit an alternator then you must reverse the battery connections, eg negative earth

As a precaution I would remove or disconnect the original wiring to avoid inadvertent short circuits!

Gerald

PS.

The diagram which you have submitted is for a three wire alternator which has battery sensing! You do not require this facility, keep it simple.

crofter · Post by **crofter** » Sun Jan 11, 2009 4:20 pm

Ben
The wireing is the same exept there are only two wires on the Lucas Alternator and I did not use a resistor. What I did on the International was join the Battery live wire at the control box to the D wire (control box to Dynamo wire) together and well insulated, this give the 12v supply to the Alternator, then for the charge light I used the field wire from the Dynamo (the thin wire)
To a light bulb holder through a switch to a 12v supply, I belive a Alternator will not work with out a charge light, at least the type I used, When the Alternator starts to charge the feed to the light from the Alternator becomes live and the light goes out,( its earthed trough the Alternator when not chargeing.

Ronnie.

crofter · Post by **crofter** » Sun Jan 11, 2009 4:22 pm

Ben
I forgot to mention I removed the old regulater compleatly and made sure all wireing conections were well insulated.
Ronnie

Jerry Coles · Post by **Jerry Coles** » Sun Jan 11, 2009 9:45 pm

I posted an offer of a wiring diagram for a Dexta including alternator wiring, see my post 21 June 2008.
For a tidy job use a proper connector available from http://www.autoelectricsupplies.co.uk/product/47.
It is essential that the Ign warning light is wired from the Ign switch, through the bulb and then down to the small connector.
I used a second hand Lucas and ir works fine.

Bensdexta · Post by **Bensdexta** » Mon Jan 12, 2009 1:43 am

Dear All, Many thanks - very helpful. Ben

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