Super Dexta Positive earth?

This forum is about the Fordson Dexta, Super Dexta and Petrol Dexta.
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agoose
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Joined: Fri Jul 15, 2011 11:12 pm
Location: Ireland

Super Dexta Positive earth?

Post by agoose »

HI,

I have a Super Dexta.

By coincidence I looked at the wiring diagram in the manual, which I downloaded from Stefan ? German site some time ago.

It shows the wiring as positive earth.

Some time ago, I had it wired as negative earth to try and get it started, which it did NOT - nothing else was wired up on it

Silly question :

If I wire it neg earth, will the starter spin in the wrong direction?

There is also a 'modern' alternator on it (no dynamo)

If I wire it positive earth, will this damage the alternator??

thanks

tmc
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Location: Devon, United Kingdom

Re: Super Dexta Positive earth?

Post by tmc »

The starter will only spin one way wether neg. or pos. earth . All alternators are negative earth . The tractor would
originally have been positive earth with a dynamo . Hope that helps .

agoose
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Joined: Fri Jul 15, 2011 11:12 pm
Location: Ireland

Re: Super Dexta Positive earth?

Post by agoose »

Thanks.

The head gasket was blown as well.

That is changed now

However, I thought I was spinning the starter wrong.

I will wire it up now and try it out

Jerry Coles
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Joined: Thu Apr 17, 2008 9:09 pm
Location: Camerton, Bath, UK

Re: Super Dexta Positive earth?

Post by Jerry Coles »

If you have an alternator you must have it wired for Negative earth.
Unlike a Generator which needs to be 'flashed' before use to give the correct polarity an alternator contains Diodes which are hard wired to convert the 3phase AC to DC so cannot be used on Positive earth systems.
If you do then be prepared for some expensive smoke as the alternator will be 'sucking' the current not 'blowing' into the battery!!
Everything else is non polarity specific.
Cheers
Jerry
Jerry Coles
Camerton, Bath, UK
West Highland White Terriers, Dexta's, E27N's and DUKW's

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