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Alternator Conversion

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Preacher John

03-09-2003 17:15:41




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Ok fellas I built a nice bracket and bolted the alternator up. I started the tractor and there was about an 8/10 of a volt on the multimeter. I was curious so I cracked the throttle and opened her up. Now the reading was 38 volts. Seriously, no kidding. I shut it of and just to check the volt meter I tested it on the battery and It read 12.4 volts so my volt meter isn't the culprit. Now what do I do? Do I have a bad regulator? Thanks, Preacher John

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Preacher John

03-10-2003 12:07:35




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
Thank you everyone for the help. Yes The alternator is a one wire. I don't know the model number however. Yesterday when I got the 38 volt reading that was from testing the terminal on the alt to the side of the alt casing. At that point the alt was not connnected to the battery. You know what they say," no brain, no headache" lol Anyway Taking all your good advice this morning did swap the battery cables so that it would be negative ground and this morning I did hook the alternator to the battery + post using 10 gauge wire. With the old A revved it would make around 14.2-14.3 volts. With the throttle almost closed, it charged at a little over 13 volts. Is this going to work? Thanks again, Preacher John

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Bob

03-10-2003 14:43:06




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 Re: Re: Alternator Conversion in reply to Preacher John, 03-10-2003 12:07:35  
Perfect voltage readings you have now!!! Glad we could help!



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Craig-MN

03-10-2003 09:15:16




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
I read through all the replies you got. Seems to be some question as to whether or not you had the battery hooked up and which polarity. Also it's not clear where you measured 38 volts.
Are you using a Delco-Remy 10SI one-wire alternator? If so it will not charge until you connect a battery to it. (Same is true for the regular 3 wire version). It needs some battery power to activate the regulator.
If you hooked up your battery as positive-ground to the negative-ground alternator you should have immediately had a HUGE arc and melted wiring and fried diodes in the alternator becasue of the reverse polarity through the diodes. You never mentioned such a happening.
If you post back with more information then someone can help you.

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G Taylor

03-09-2003 22:07:09




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
Not trying to smart or hurt anyone's feelings here but.... There have been a lots and smoke,sparks,fires, ruined parts,cussing, lost production,wasted time and frustration when the "superior-cheaper-easy" alternator conversion is performed by amateurs. Can't go wrong with a simple wire by wire install/replace of the original generator. They can even be hopped up for 25 to 30 amps output during overhaul. Charging problems are sometimes due to worn belt pulleys and no fault of the generator. I've watched some operators start/stop the tractor every few minutes during puttering around jobs, even just to open close gates. No charging system can keep up with that demand.

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John T Update (Dont fry that new alternator)

03-09-2003 18:20:43




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
Hey Preacher John, None of us want you to harm that new alternator, so if its designed for negative ground, first install the battery with its neg side tied to the tractors frame and the pos would be what goes down to the starter and if it happens to have any extra wires (may have been added over the years) that were tied to the ungrounded side of the battery, tie them to pos also. Then if it has an ammeter, its wires would have to be swapped from side to side so it reads correct. Next we will address any coil reversing that may or may not be necessary depending on what ignition and components you have. The next time you take voltage readings, do it AFTER the alternators output is connected to the battery, again usually via a wire to the ammeters load (non battery) side or else at the starter post or battery itself. On some alternators, when you make that battery attachment you will get a spark. Be CAREFULLLLL LLL Ol John T

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Preacher John

03-09-2003 19:22:35




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 Re: Re: Alternator Conversion in reply to John T Update (Dont fry that new alternator), 03-09-2003 18:20:43  
So because I have bought a negative ground alternator, I need to switch the rest of the tractor to negative ground. I can do that but since its a DC system won't the starter then spin backwards? Is there something I can do to the starter to reverse the way it spins so I can go to neg. ground? Please bear with me here I don't claim to know much about electronics. Thanks, Preacher John

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John T

03-09-2003 19:43:52




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 Re: Re: Re: Alternator Conversion in reply to Preacher John, 03-09-2003 19:22:35  
Nope, the starter will still turn the correct same direction REGARDLESS if youre pos or neg ground. No need to worry about it. Its the orientation BETWEEN the armature and field that determines direction, and you dont change that when you simply reverse its polarity. The neg ground alternator is fine, I think you can get them positive ground, but no need to do that and they may be more expensive. John T

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Clooney

03-09-2003 18:02:52




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
John, without a load on the output post the internal regulator can't keep up with the voltage regulation. You will need a battery load on the B+ stud on the back of the alternator to get a decent voltage reading. With the B+ post hooked a battery load [preferably through the ammeter] the voltage across the battery posts should be real close to 14.2 volts [hot]. If your alternator is above 55 amps [should be stamped on the alternator case] you should use 10 ga. wire from the alternator B+ stud to the ammeter & from the ammeter to the battery. If it's 55 amps or under you can use 12 ga. wire.

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John T

03-09-2003 17:56:26




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
Hi again Preacher man, Well, was that voltage reading taken AFTER the alternator was connected to the battery??? I doubt it. An unloaded open alternators voltage reading isnt what it would be if connected to a battery. The state and condition and voltage of the battery affects the alternators current and voltage output, i.e. its regulator circuit. The alternators output needs to be connected to the battery to ever charge it, and thats usually via a No. 10 or 12 wire up to the load (non battery) side of the ammmeter. If it has no ammeter, its often connected to the battery via the starter post. Is this a negative ground system now??? Most of those alternators are for negative ground systems. If its a one wire alternator, check and see if the wire you connected to its output has battery voltage on it???? It needs it, and should be 10 or 12 gauge depending on the current rating of the alternator . Let us know. Ol John T

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Bob

03-09-2003 17:30:28




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 Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:15:41  
The output stud on your alternator should be connected to the "+" post on your battery, whether directly, or through an ammeter, so the voltage would read the same at these 2 points.. If you have such a wide discrepancy in voltage readings, you obviously do not have a complete circuit between these points. The regulator in the alternator may have been killed by this fiasco, or it may work fine when you get it properly connected.

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Preacher John

03-09-2003 17:59:45




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 Re: Re: Alternator Conversion in reply to Bob, 03-09-2003 17:30:28  
Bob, if I convert from generator to one wire alternator, must I also convert the tractor to negative ground? It was positive ground originally, and that is the way the starter is wired so far. Thanks, Preacher John



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Bob

03-09-2003 18:06:44




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 Re: Re: Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:59:45  
You must hook up your battery ground the same as the alternator you have acquired is set up for. THERE IS NO SECOND CHANCE WITH THIS!

I you want to retain positive ground, you'll have to hunt down a positive ground alternator!



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Preacher John

03-09-2003 17:44:56




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 Re: Re: Alternator Conversion in reply to Bob, 03-09-2003 17:30:28  
Bob, I have put the tractor together except for the wiring. The battery is not yet hooked up to the alternator. If I did hook the alternator up to the battery wouldn't it still read 38 volts? sorry about all the dumb questions. Preacher John



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Bob

03-09-2003 17:57:27




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 Re: Re: Re: Alternator Conversion in reply to Preacher John, 03-09-2003 17:44:56  
No, it wouldn't, as the battery would provide a load for the alternator. Generally, it is never good practice to run an alternator, or a generator, without it properly connected to a load (battery).

I think you had some earlier posts about this, but was it a one-wire alternator conversion?



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