ballast resistor/ IH 184

The alternator on the IH 184, I recently picked up, isn't charging when connected through the ballast resistor, which is mounted on the alternator. The auto electric shop that tested it says it puts out 14.1 VDC by itself but won't put out anything through the resistor. This is how it was connected when I got the tractor.

The ballast resistor is rated at 25 ohms & I'm reading 24 on my meter.

Coming from the alternator, can I simply bypass the ballast resistor?

Thanks,

Gary

I bet that ballast resistor is used in conjunction with the ignition points. I know on a 1979 Farmall 140 we had the ballast resistor for the ignition points was mounted on the alternator and it was an original tractor. Better trace the wires (and get an original diagram to double check) before bypassing anything!

Thanks, sounds like a good idea.

Pilot, a Ballast Resistor used on coil ignition systems is more like 1.2 to around 2 ohms NOT 25 ohms. If a 25 ohm were used as a ballast resistor on an ignition system there wouldn't be any spark.

When people used a Delco 10SI type of 3 wire alternator they often used a diode while some such as myself used a 10 or so ohm resistor to prevent ignition feed back and run on. But that was in the EXCITATION circuit from the ignition or coil to the small side No 1 terminal on a 10 SI Delco alternator I HAVE NO IDEA WHAT YOU HAVE OR HOW ITS WIRED.

The big main output on an alternator would NOT go through a 25 ohm ballast resistor, it would go to an ammeter or the dash so it gets to the hot battery post eventually.

I don't know if yours is an excitation circuit resistor (like 3 wire Delco 10 SI used) or what it is but I dont see a 25 ohm ballast in the alternators big main output regardless of what alternator you have.

John T

That wiring is wrong, at the top of the page in search for box, type in Bob M's wiring diagrams and that should give you an idea of how it should be, although I have no idea what a 184 looks like under the hood and behind the dash.

Thanks for all the help boys. John T you hit the nail on the head! I got the NAPA ICR13S ballast resistor & it's right on 2 ohms.

I got 'er up & running, charging the batt. at 13.8VDC.

Thanks to all for the input.

Now if any of y'all have experience with the model 3160 belly mower (60" cut) I'd love to hear from you. This thing will kill the engine when flipping the switch for the pto, unless the tractor is driving ahead! Sitting still it will bog the engine down & then kill. Once the mower deck is spinning there's no problem stopping or going ahead.

Is it possible that the battery (which is new) needs to recover from not being charged by the alt. thereby robbing the engine of sufficient voltage to run or should the alt. be enough to keep it running???

Cool and congratulations, thanks for the feedback. Heck even a blind squirrel finds a nut now n then lol

I would think a good alternator (and good tight belt???) would supply sufficient amperage to be charging the battery PLUS supply momentary current to engage an electric clutch (if you have one???), but Im NOT familiar with that tractor nor the PTO or whatever engage requirements (if its even electric clutch???) so Id just let her charge a while n then see what happens. I wonder if theres some sort of a safety interlock switch that's bad or mis adjusted that's killing the engine ignition temporary??? I REALLY HAVE NO CLUE ON THE MOWER PROBLEM. Im NOT much of an IH man other then old tractor electricals

John T

Yea John, it has an electric clutch that engages a double belt driven shaft that's parallel to the main shaft.

This is a 184 Loboy which was a spin off from the Cub tractor. A lot of people used them to mow with or for folks up north they can attach a snow blower. It's small but not a bad tractor for a small place.

Thanks again for the help.

Gary

As John has posted the 25 ohm resister is indeed part of the alternator excitation circuit. It serves a dual purpose. It protects the electrical system if the connection should fail between the battery output stud on the alternator and the battery. If that were to happen all the charging current would flow back through the #1 terminal to the ignition switch. The small wires in that circuit are not designed to carry charging current. It also add a resistance in that circuit so that the alternator does not back feed the ignition switch and prevent the engine from being shut off.

As long as you are not having problems shutting off the engine the 1.8 ohm resistor you replaced it with will function OK but you have lost some of the circuit.

The battery circuit failure is not very common. In 40 plus years of working on tractors I ran across it for the first time last summer. The battery lead had broken in the harness near the alternator creating an open circuit. The charging current flowing through the 25 ohm resistor had also burned it out. Since the customer had already replaced the alternator I do not know if it too had been damaged but the replacement unit would not start to charge due to the open resistor.

If the engine on my 184 has not been fully warmed up, I often pull the choke lever out slightly just before I engage the electric clutch switch. Otherwise engaging the clutch and starting the mower deck can kill the cold engine. Once the engine is at working temp, killing the engine shouldn't happen.

--Lee

Hmm, the part about the mower killing the engine unless the tractor is moving is a strange one. It takes MORE engine power to move the tractor and spool up the mower, than it takes to spool up the mower just sitting there.

If the problem were electrical, I would expect the tractor to just stop dead like you turned off the ignition, not bog down. Does the engine recover if you immediately disengage the PTO?

First thing I'd do is loosen the drive belt and see if all your spindles are turning freely. Next, I'd try to fire up the PTO with nothing connected.

Thanks Owen I'll try it out when I get back on
the tractor.

Lee & Mkirsch thanks for the suggestions on
the mower deck. I'm not 100% sure that I've got
the right belt as it was really tough to put back
on when it was first delivered. Judging from the
noise made by the mower alone I've likely got a
spindle bearing going bad.

Thanks again to all for the help.

Gary

(quoted from post at 07:46:06 07/23/14) Hmm, the part about the mower killing the engine unless the tractor is moving is a strange one. It takes MORE engine power to move the tractor and spool up the mower, than it takes to spool up the mower just sitting there.

Click to expand...

In this case, the inertia from the motion of the tractor is probably helping to get the mower spinning. The tractor speed would momentarily decrease as inertia is transferred to the mower then the engine brings them both up to full speed.

Owen, I checked & you are right, the tractor
now WILL NOT shut off by turning the key.

I didn't notice it at first because I only use the
tractor every 10 to 12 days so I turn the gas off
until it kills. Our humidity is so high down here &
I find this helps minimize carb problems on a
sitting tractor.

The new 2 ohm resistor is wired exactly like the
old one, which is to say that the lead leaves the
resistor & runs down to the positive side of the
coil. I believe that is also how the schematic
shows it as well.

How can I get this thing to shut off by the key &
still charge the battery when running?

Gary

John T,
I thought I had this thing cleared up. After changing to the 2 ohm ballast resistor the batt. is charging at 13.8VDC. However, just like Owen had mentioned, now my tractor will not turn off by key.

The wiring schematic shows that a lead leaves the ballast resistor & attaches at the positive terminal on the coil, which is what I have.

Do I need to isolate the key ignition somehow?

Gary

(quoted from post at 03:10:40 07/24/14) Owen, I checked & you are right, the tractor
now WILL NOT shut off by turning the key.

I didn't notice it at first because I only use the
tractor every 10 to 12 days so I turn the gas off
until it kills. Our humidity is so high down here &
I find this helps minimize carb problems on a
sitting tractor.

The new 2 ohm resistor is wired exactly like the
old one, which is to say that the lead leaves the
resistor & runs down to the positive side of the
coil. I believe that is also how the schematic
shows it as well.

How can I get this thing to shut off by the key &
still charge the battery when running?

Gary

Click to expand...

Go back to a 25 ohm resistor. If you are sure your old resistor has the correct ohm reading,put it back in and see if it works.

Does this tractor have an ignition resistor between the switch and coil? If you are running 12 volts directly to the coil without any resistor a 25 ohm resister should work without any problems. That is the system that IH used on their diesel tractors when using a 10SI alternator. Many of the tractors with gas engines used a diode instead of the resistor. If yours will not work with the correct resistor you could switch a diode.

One other possibility is that the brushes are getting worn in the alternator. If the alternator uses sliding brushes rather than swinging brushes you may have a situation when a brush was hung up enough to cause a poor connection to the slip ring. That could make it not charge. Removing the alternator from the tractor and taking it to be tested may have causes the brush to come free and allow the alternator to begin charging once again.

The electronic component is probably not a resistor, but a DIODE.

The wire running back to the coil is the power used to excite the alternator at startup. The coil is just a convenient source of switched 12V power in this case.

It needs a diode to prevent backfeeding the coil from the alternator. That's why it won't shut off with the key.

Install the diode with the "arrow" pointing toward the alternator.

Lee, Mkirsch, Jim & Owen, thanks for all the input.
I'll get a diode installed.

I didn't intend to draw this post out so long.
Thanks again,