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Ferguson TO20 alternator question.

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craigspain

05-18-2008 14:22:09

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I bought a 12volt 1 wire positive ground alternator to replace my 6 volt system due to generator failure. I made the bracket, replaced the coil, belt, battery, bulbs and start solenoid.

When I hook up the alternator wire I get a big spark.
I checked with a volt meter from the alternator wire to the battery negative and get 12volts then 13.5 with it running.
Without the alternator wire connected the tractor starts and runs well.
I have the alternator wire connected to the ammeter then to the negative battery terminal.

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Bob (Aust)

05-20-2008 05:11:06

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

[quote:08329eddf7]"...a full wave bride four diodes rectifier..."[/quote:08329eddf7]

Brides no doubt rectify husbands, about one day after the wedding ... but I intended to state:

"...a full wave bridge four diodes rectifier..."

A "full wave bridge rectifier" "converts" (or rectifies) an alternating current (AC) to direct current (DC), required to recharge the battery.

Bridge Rectifier.

One Wire Alternator.

Disadvantage of a one wire alternator.

I personally believe that a well tuned engine, a serviceable generator and a good battery is cheaper and far better than a "One Wire Alternator", any day, regardless of whether the system is 6 volts DC or 12 volts DC!!
But that is just my opinion. :lol:

Bob in Oz

'53 TEA20

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Bob (Aust)

05-20-2008 04:55:45

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

AussieDoc.
[quote:be31f047ff]"How does a single wire alternator work? One wire?"[/quote:be31f047ff]

I haven't seen one in Australia but I think in principal, they consist of an AC "generator", rectified to DC with a diode rectifier (the same as most automotive alternators, a full wave bride four diodes rectifier), then have an in-built solid state regulator, so the alternator output is a pure DC current, which connects direct to the battery and is sensitive to the battery's current requirements.
Bit like a generator and voltage regulator combined.

No need for an external regulator to vary the voltage to what the battery requires to re-charge, as the regulator is built in.

The "one wire" thing means the DC positive goes direct to the battery, whilst the DC negative finds it's way to the battery via a common earth through the tractor frame and battery earth lead.
At least that is the theory of how I suspect they work..... ..... :lol: :lol:

If I'm wrong, someone will be come along to correct my errors.

Bob in Oz

'53 TEA20

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craigspain

05-19-2008 18:59:20

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

Thanks to all who responded.
JMOR, you ended up being correct. After reading all of the replys and went back and did some rechecks., I found that the positive ground alternator that the guy at NAPA sold me was actually a negative ground.

John (UK) I did replace most of the wiring and I replaced the start switch due to it being cracked.
I ended up reading another article about converting from positive to negitive ground and then after checking a few more sources I bit the bullet and tried it since I had a negitive ground alternator and a wired field coil in my starter.

I reversed the battery cables and coil terminals and tested the tractor with the alternator disconnectod. All worked perfectly.

Then just to be on the safe side, I added a 25 amp breaker to my coil wire to test it in case i had another short.

I hooked up the coil wire without a spark. fired the tractor up and the amp meter read 20 amps to start and dropped as the battery charged.

I bushhogged 2 acres afterward in the dark after finishing.
I was going to replace my 6 volt headlights but I had already spent enough for 1 week so I rewired them in series .

Thanks again.

Due to all of the headaches involved in making this conversion work, I will document everything including part numbers for the parts and post it herein the near future. AussieDoc the mount of the alternator is grounded to the frame and the 1 wire goes to the to the ammeter then to the battery positive

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John (UK)

05-19-2008 13:27:28

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

There should have been no need to replace the starter switch,if the correct one was fitted in the first place, you don't say anything about replacing the wiring, if you have tried to make do with the old wiring it may not work and you may have other things wrong as well. If you want the wiring diagram, email me and I will send it...John

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Griz

05-19-2008 04:55:46

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

Try hooking it up to the + terminal.

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AussieDoc

05-18-2008 16:44:01

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Re: Ferguson TO20 alternator question. in reply to Bruce(OR), 05-18-2008 14:22:09

How does a single wire alternator work? One wire?

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JMOR

05-18-2008 15:09:18

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Re: Ferguson TO20 alternator question. in reply to craigspain, 05-18-2008 14:22:09

Are you SURE you bought a POS gnd alt? Those are pretty rare! I guess if it measures neg 13.5 volts, then that's what you have got.

There should be no spark when connecting the alternator. Sparks usually occur when Bat and alt are at cross polarities & usually result in ruined alt.

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Bob

05-18-2008 21:02:51

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Re: Ferguson TO20 alternator question. in reply to JMOR, 05-18-2008 15:09:18

It is also possible to recharge a dead battery to reverse polarity by mis-connecting the charger.

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