Hot generator

Brian Glynn

New User
1948 8n with front distributor--

What would cause my generator to become so hot that it discolors the paint? I noticed a slight wobble in the pulley so I have the generator being rebuilt this week with new bearings, brushes, etc. I also noticed the battery doesn"t have as much "ooomph" when turning the engine over lately. In addition, I overheated the other day, but it was 90+ degrees in northern Minnesota and I was working the girl hard while brush-hogging.
 

I would have the battery checked. If the battery has a short in it it may be drawing to much current flow which would make the generator hot. If it was polarized wrong, it would not charge the battery and I doubt that it would make it hot. A short to ground would make it hot but that probably would fry the wires.
 
Brian........surprizingly enuff, generators run HOT (ittza electrical thing) ...but... NOT burnie-burnie HOT. Before you haul yer 6-volt genny into real generator repair shop. RE-POLARIZE yer genny. With the tractor OFF, arc-spark the side-by-side ARM and BAT connections together on yer squarecan voltage regulator under yer oil pressure gauge. Me? I use a stubby wideblade screwdriver. You can use bailin'warr iff'n you want. Now start yer tractor and watch yer amp-meter over yer left kneesie. You should gitt about 3-5 amps charge (+) at about 1/3-throttle. Unlike 12V-alternators in yer automobile, 6-volt gennys do NOT CHARGE at idle.

Remember, you do NOT WANT high charge (+) after the initial surge of amps 'cuz you'll BOIL all yer battery ACID out and WARP yer lead plates and haffta buy a NEW 6-volt battery. .......the charged Dell
 
(quoted from post at 18:54:25 08/25/13) 1948 8n with front distributor--

What would cause my generator to become so hot that it discolors the paint? I noticed a slight wobble in the pulley so I have the generator being rebuilt this week with new bearings, brushes, etc. I also noticed the battery doesn"t have as much "ooomph" when turning the engine over lately. In addition, I overheated the other day, but it was 90+ degrees in northern Minnesota and I was working the girl hard while brush-hogging.
orget the polarizing.........if it is heating that much, it is generating. Take the VR to the re-builder, too & have him check generator WITH regulator. I expect that cut out portion of VR is not closing, so generator outputs like crazy, over powering the field coils & making a lot of heat! Just not connected to battery, thus no charging.
 
JMOR, I am having a problem getting my mind wrapped around what you are saying. You are saying that if the cutout relay does not close, that will make the generator overheat? Where does the current flow go if the cutout does not close? Not doubting, just don't understand! I got one that the cutout does not close and I will have to check to see if the generator gets hot.
 
I am looking at a VR and see that the current flow goes to the voltage coil before going to the cutout coil so I somewhat understand what you are saying. I need to learn how a VR does what it does!!LOL
 
(quoted from post at 22:20:24 08/25/13) JMOR, I am having a problem getting my mind wrapped around what you are saying. You are saying that if the cutout relay does not close, that will make the generator overheat? Where does the current flow go if the cutout does not close? Not doubting, just don't understand! I got one that the cutout does not close and I will have to check to see if the generator gets hot.
enerator field coils are powered from inside generator.
 

I have same issue on my '48 8N. It gets really hot (not scorch the paint hot, painful to keep your hand on it hot) but it charges well, voltage output isn't excessive, new VR, I keep the bearings oiled, it's been polarized properly when I put the VR on earlier this year. Battery is about a year old and spins it over pretty well, starts right up and runs well. I had to take the genny apart to clean it when I first got this tractor, about 5 yrs. ago, it was not charging. A little cleaning fixed it up.
 
(quoted from post at 10:39:01 08/27/13)
I have same issue on my '48 8N. It gets really hot (not scorch the paint hot, painful to keep your hand on it hot) but it charges well, voltage output isn't excessive, new VR, I keep the bearings oiled, it's been polarized properly when I put the VR on earlier this year. Battery is about a year old and spins it over pretty well, starts right up and runs well. I had to take the genny apart to clean it when I first got this tractor, about 5 yrs. ago, it was not charging. A little cleaning fixed it up.
verage joe can keep his hand firmly on 140F, but not 160F. GM Arizona proving grounds on a 103F day has recorded alternator temperature of 305 to 433F, depending on where on alternator the temperature probe was located. So, your generator isn't REALLY hot. Think about it...it is mounted to an engine that will be over 200F, so in time even if it made no heat of its own, it would still be quite warm-to-hot.
 
(quoted from post at 15:33:30 08/27/13) Typically, that point is reached just BEFORE the smoke begins to leak out!
.....and with the insulation technology of yesteryear generators, I expect about 300F would be in vicinity of that smoke point. At 400F, you are likely on the short fuse! If I spit on it & it sizzles (212+), I would look into it.
 
I brought the generator into an auto electric shop who noted that the bearings were shot which caused the armature to rub against the coil which caused excessive heat. $160 to rebuild or $50 for a used one. I opted for used. Thanks for all your advice.
 
(quoted from post at 19:39:48 08/29/13) I brought the generator into an auto electric shop who noted that the bearings were shot which caused the armature to rub against the coil which caused excessive heat. $160 to rebuild or $50 for a used one. I opted for used. Thanks for all your advice.
lad you are back to tractoring. All heat problems don't have to be electrical. Armature dragging, bad bearings themselves, even without armature dragging make heat. Overheated railroad car bearings have started fires.
 

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