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W400 keeps burning up alternators


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As the Bat wire goes from the ammeter to the regulator how could you connect the other end to the alternator if you moved one end to the L terminal?  Why pick the L terminal.  To my way of thinking and I have wired up dozens over the years using the regulator as a terminal board You should have hooked the bat, gen, and lights all on the bat post on the regulator  instead of running current in and out of the regulator.

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I would suggest doing circut resistance tests on both the + side and - side of the circut . It is a pretty simple test .

Take a volt meter  I prefer a digital one but an analog will work .

Positive side :

Place 1 lead on the output terminal of the alternator and the other directly to the + post of the battery . Start the tractor and check what the meter reads . It should not read more than .5 volts and preferably less than .5 volts . If it reads more than that that tells you that the electricity finds it easier to go thru your meter leads than thru the wire which indicates that there is high resistance in the output circut between your alternator and your battery . You have your sensing wire hooked up to the output stud on alternator which is fine but it is sesnsing the voltage drop due to circut resistance which kicks the alternator up to try to overcome it and the alternator will do what it needs to to try and charge the battery and will burn itself up in the process trying to accomplish this .

To remedy this one has to check/clean all connections on the + side of the system .

Negative Side :

Put 1 voltmeter lead on the alternator and 1 on the - battery post and do the same process as on the + side of the circut.

We all know the import electrical stuff now a days is basically junk but I find it hard to believe that there are 4 bad alternators and something is causing them to fail .

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On 6/5/2023 at 12:21 PM, HydroTek said:

You have a failed alternator on the tractor now ?

Yes. I'll have to take some time to pull the hood to fiddle with wires for you. I could reach up in there and get a probe on the stud easy enough but I'd rather have the hood off for this, and I'm probably going to have to replace the alternator again anyway.

22 hours ago, carmine@1945 said:

Your first post says you did a generator to Alternator conversion.  You had to be bored or did the generator fail?   I you did the conversion because the generator failed, then whatever that caused the generator to fail, is still not fixed since you've gone through four alternators.

No. As I recall the generator worked fine. The batteries, and starter, did not. New starter, new cable, new batteries, clean connections... R----R----R, would barely turn over. Waste of money, so we put the old starter back on and sent the new one back. 

What could be causing this though? The only thing capable of producing enough Voltage to fry an alternator, is the alternator. Battery voltage couldn't do it.

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5 hours ago, IHC_1470 said:

Can you explain why a resistor or diode will not work?

A resistor has a failure mode of open I.e. no circuit.

 A light bulb also has a failure mode of open, but also has a visual indicator, no light when  the Ignition switch turns on,  equals a problem.

 A diode has two failure modes, open and shorted.

 Open mode failure, the alternator will not excite., just like burned-out bulb or open resistor.

 Shorted failure, will give battery voltage on the number 1 wire at all times, which can cause problems such as the original poster is experiencing.

 

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10 hours ago, supermechanic said:

A resistor has a failure mode of open I.e. no circuit.

 A light bulb also has a failure mode of open, but also has a visual indicator, no light when  the Ignition switch turns on,  equals a problem.

 A diode has two failure modes, open and shorted.

 Open mode failure, the alternator will not excite., just like burned-out bulb or open resistor.

 Shorted failure, will give battery voltage on the number 1 wire at all times, which can cause problems such as the original poster is experiencing.

 

I am sure you realize that IH in the day wired electrical systems for both gas and diesel  powered machines using an solenoid shut off with a diode in the #1 circuit. The machines I am thinking of had an amp meter for a charge indicator. The purpose of the diode was to prevent a back feed from the alternator to the solenoid which would prevent the engine shutting down. Those systems worked quite well and had no light in the #1 circuit.

They also used a resistor only in some models of tractors that used a voltmeter for a charge indicator.

I understand what you are saying yet to say the system will not work with a resistor or diode IMHO is a false statement. IH used both designs in many of their systems over the years.

 

 

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It takes voltage or heat to destroy semiconductors. From what I have read here. I think it is mounted the same place the generator was. So heat should be okay. There are only three sources of voltage strong enough on the tractor that I can think of. The ignition coil, the condenser and the alternator itself. If #1 wire does not pass near any of the secondary wires that can be eliminated. A very long shot would be if #1 was connected to distributor side of coil. The 8 or 9 volts there would probably start the alternator and the diode would keep the alternator from killing the ignition but could expose the regulator to the spark from the condenser. A very long shot.

While it is the regulator that is failing. It occurs to me that the diode trio maybe the component causing this. I have been finding lately that Chinese components are likely to have a 30 volt limit. While the field current is DC . The stator current is ac. The diode trio rectifies this and supplies the field current. Ac voltage is double the rectified voltage. If one of the diodes in the trio would leak. You would be exposing the regulator to ac voltage. With a 14.8 regulator that would be 29.6v.

Most of you are thinking of this as a one tractor thing. You are ignoring Dale who is reporting the same failure on multiple units.

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We need to know how the #1 wire is connected to the tractor -- location of the connection point is important to the amount of voltage the wire can be exposed to

There is quite a voltage "kick" that is returned from the primary side of the ignition coil, the condenser is supposed to suppress most of this -- but with today's electronic parts, you may have problems connecting at the ignition coil for the #1 power

Measuring the voltage on the #1 wire would be a start to figuring this problem of trashing alternators

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45 minutes ago, HydroTek said:

We need to know how the #1 wire is connected to the tractor -- location of the connection point is important to the amount of voltage the wire can be exposed to

There is quite a voltage "kick" that is returned from the primary side of the ignition coil, the condenser is supposed to suppress most of this -- but with today's electronic parts, you may have problems connecting at the ignition coil for the #1 power

Measuring the voltage on the #1 wire would be a start to figuring this problem of trashing alternators

He has stated he is hooked to plus side of coil with diode. Voltage there is going to be charging voltage. The kickback you're talking about would be on distributor side . Would take a capacitor and diode in test lead to measure. I believe they call that a tva or true voltage adapter.

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A scope would be the best test instrument, but not everyone has that available -- most meters that people commonly have are not "fast enough" to catch the voltage spikes

What I was getting at is that is there is a bad connection between the battery side of the ign coil and the battery -- the voltage there can be much more that battery voltage -- because of the coil kick back

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23 hours ago, Matt Kirsch said:

What could be causing this though? The only thing capable of producing enough Voltage to fry an alternator, is the alternator. Battery voltage couldn't do it.

This is kind of a misleading thought.  It sounds to me like the “alternating” portion of your alternator is just fine; it’t the voltage regulator that is not doing its job.  That is the only way I can see that you could get a 19+V reading out of the system.  It would seem the diodes and rectifiers are fine too yet. 

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Never going to get a consensus here. Just switch it out for a one wire. Something current like a denso or delphi. Of course I said something current so probably something I never heard of.

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1 minute ago, snoshoe said:

Never going to get a consensus here. Just switch it out for a one wire. Something current like a denso or delphi. Of course I said something current so probably something I never heard of.

But why is one of the easiest mods to a farmall that has been done thousands of times having problems on this one tractor?? 

I still think it's a wiring/connection issue that's being overlooked.

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19 minutes ago, Dan Robinson said:

But why is one of the easiest mods to a farmall that has been done thousands of times having problems on this one tractor?? 

I still think it's a wiring/connection issue that's being overlooked.

So you think Dale is lying or Matt is giving incorrect info? If he takes an alternator that has been working fine on another machine and it does the same thing. Then I will believe your argument. 

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3 hours ago, snoshoe said:

So you think Dale is lying or Matt is giving incorrect info? If he takes an alternator that has been working fine on another machine and it does the same thing. Then I will believe your argument. 

Not necessarily, just find it hard to believe he's gone thru 4 alternators all having the same problem, all on the same tractor. New parts are quite crappy, I know that, but I think there's something going on yet.

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I’m not a proponent of the one wire alternator fix.  To my knowledge, those alternators usually need to be spun fast enough to get initial excitation, and too often just putzing around doesn’t get the alternator spun fast enough to get to that point.  I have had that kind of charging problem on 3 wire alternators on a machine that didn’t have a dedicated excitation circuit, and the result is a discharged battery.  I added an excitation circuit to solve that problem.  Not sure that can be done on a one wire.

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One way to determine if it is an alternator or wiring issue is to run some new/good wires from the battery to alternator. Does not need to be permeant for testing. Run a 10 or 12 gauge wire depending on amp rating of the alternator. Run a 16 gauge wire to #1 terminal and loop a wire from the battery stud on alternator to #2 as you said you have done. Put an alligator clip on the 16 gauge wire to easily connect to the battery. You can wire a light into #1 if you wish. Sounds like you have a voltmeter so use that to monitor voltage. Go run it and see what happens. No need to get to the ignition switch or amp meter for connections for testing purposes. Will be interesting to hear what you find out.

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On 6/8/2023 at 12:12 AM, IHC_1470 said:

One way to determine if it is an alternator or wiring issue is to run some new/good wires from the battery to alternator. Does not need to be permanent for testing. Run a 10 or 12 gauge wire depending on amp rating of the alternator. Run a 16 gauge wire to #1 terminal and loop a wire from the battery stud on alternator to #2 as you said you have done. Put an alligator clip on the 16 gauge wire to easily connect to the battery. You can wire a light into #1 if you wish. Sounds like you have a voltmeter so use that to monitor voltage. Go run it and see what happens. No need to get to the ignition switch or amp meter for connections for testing purposes. Will be interesting to hear what you find out.

Yes, start simple!

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