Generator charging

I have two questions after performing the electrical checks John T described.

1. When I hook the field post on the generator to ground and the hot to ARM, the generator runs. When I REMOVE the ground as you suggest, it slows.Does this mean the brushes are worn down?
Does this have any negative meaning or what?(The generator will put out 20 amps when I manually hold the regulaot contacts. )

2. The engine is running then stopping and it is getting fuel. BUT when I put a voltmeter on the coil on the post coming from the ignition switch, there is a wild fluctuation on the needle. The engine , I notice dies when the voltage starts to drop. I say this is a bad voltage regulator, is this right? Thanks

QUESTION 1. When I hook the field post on the generator to ground and the hot to ARM, the generator runs. When I REMOVE the ground as you suggest, it slows. Does this mean the brushes are worn down?
Does this have any negative meaning or what? (The generator will put out 20 amps when I manually hold the regulaot contacts.)

ANSWER

WAIT A MINUTE The Motor test should begin with the gennys frame/case obviously grounded,,,the Gennys Field post temporarily jumped to the frame/case (ground),,,,, and then hot to the ARM post n she ought to spin indicating the Armature n Brushes n Commutator are alllll okay BUT THEN YOU REMOVE THE FIELD POST CONNECTION FROM THE FRAME/CASE/GROUND NOTTTTT TTT THE GROUND ALTOGETHER she should spin FASTER cuz youre eliminating some back emf. If it dont spin faster when Field is ungrounded, I suspect a bad or open or shorted etc. Field winding. But I doubt you removed the ground from the genny cuz then she wouldnt spin at all""""" """ From what you describe there may still be a minor Field problem, however, like a high resistance short to case somewhere as theres a bunch of wires wound alllll around 2 sets of field poles and the place where the 2 windings are spliced so she might throw a good high charge for a short time but once things heat up she may go bonkers sooooo oooo try just the new VR FIRST as that sounds bad and we will leave the jury out on the Genny until it has time to warm up!!!

Still the fact that she spins PLUS the fact that you can make her charge at 20 amps by manually messing with VR contacts leads me to believe the Genny itself is okay (at least until things warm up as discussed above) so there must be a Voltage Regulator problem. You asked about worn brushes, if they or the armature are very bad, I wouldnt expect it to maintain a good 20 amp charge (as you claim) for any extended period..... . Id still clean up n polish the commutator n clean any copper or grit between the segments and exercise n light lube the brush hold down spring assemblies as needed so they hold the brushes down tight..... .. QUESTION

2. The engine is running then stopping and it is getting fuel. BUT when I put a voltmeter on the coil on the post coming from the ignition switch, there is a wild fluctuation on the needle. The engine , I notice dies when the voltage starts to drop. I say this is a bad voltage regulator, is this right?

ANSWER

I agree with Denny on this one. The ignition Switch sounds bad to me cuz there ought to be a steady constant voltage on the coil when the switch is on UNLESS the VR is so bad its whats causing rapid voltage fluctuations. Its common for switch contacts to get burned or carboned up or loose fitting making poor high resistance temporary contact. A way to test this is use a hot wire to feed the coil temporarily n the coils input voltage should stay at near battery voltage then and constant and she runs.

Yep Ima thinkin you need a Voltage Regulator for starters and possibly an ignition switch BUTTTTT TT try just the VR first cuz maybe if its fixed the switch aint so bad after all once you get and maintain good voltage?? Then if she charges a while but then once warm field problems develop, the genny needs attention also.

Sorry no quick easy answer on this one but with conflicting testimony (can charge 20 amps buttttt motor test isnt whats Id expect) its hard to say over the net. Maybe you will luck out and a new VR will casue the genny to charge fine and find the switch isnt so bad after all once you get good full maintained battery voltage !!!!! !

John T

I thoguht I would thake tis opportunity to write with some new information on the problems wiht my D-17 charging/starting.

Problem One: SOLVED. As you may remember I ahd intermittant voltage going to the negative side of the coil. I found that on the ignition swich lead this was a VERY poor connection. I cut off the bad one and put a new conector on.
So, now the tractor starts and runs good without fail. this is one of two problems out of the way.

Problem Two: After installig a New, american made VR, I STILL have the problem of a low read, that goes to a full spike, say 16 v, then back down again to almost 13 volts. This is with voltmeter leads on the gen output and ground. Also across the battery. Low voltage across the board.

If it matters, when I look into the rear of the generator while it is running I see NO sparking, or arcing of any kind in there. I even put a small light and put on my reading glasses and this is what I got.
(Makes those one wire alternator kits look REAL GOOD right about now!)

So, any ideas? I think that perhaps the brushes are so far down that this is making the genny "spike", but I am open to your words of wisdom!

All the best,

I have a question if you please.

When looking at the coil on the side of the engine, the terminal on the left side comes from the ignition switch.
I took a reading with the key on and it reads battery voltage. However after started when this reding is high the engine runs. After a while the voltage starts to oscillate, this voltage reading dropping to below 8-6, then increasing, then back down again and the engine dies.

Any thoughts aside from the VR needing attention/ replacement?

Thanks

HOWEVER if the battery is in poor shape (dead cells etc or sulphated) n isnt charged well its more likely its voltage might change more rapidly and be more dependant on what the Genny n VR are doing.

Thats why I earlier mentioned that if the VR was good n you had a good battery perhaps you might NOT have any ignition switch problem (but could still be so try to hot wire n see what happens) so get the VR working n get the battery n its voltage up to snuff n maybe coil voltage will be fine.

Has the battery been load tested??? Is there electrolyte above all its plates??? Do any cells show a gray or milky color??? I ask this cuz if its NOT an ignition switch problem causing erattic coil voltage it would take a poor or not charged or just shot battery that changes its voltage so rapidly as you described.

YOU GOTTA TRY TO HOT WIRE THAT COIL N THEN MEASURE VOLTAGE TO TEST THE SWITCH

This is kinda where we left off,,,,,Suspect the VR,,,,, ,,, (make sure battery is okay also),,,,, ,,,, If the colil still shows jumpy voltage then suspect the ignition switch

Let us know how she turns out

John T

I had the battery checked throughly at the auto store, adn they said it was goo; it only needed a charge. Whe I did charge it up at home it showed 5 amps initially, then after a few hours traced down to about 0 amps.

With the voltage "flucuations" I described, I remember a mechanic once said that a bad condenser will casue the tractor to run rough and then die. The THING is that he never had a voltmeter hooked up to the negative side on the coil , leading from the ignition switch, as I had. So..... another thing for me to try. I have these parts coming, and hope that this helps.

I am also going to get a point file and see what I can do with the VR. I can"s se well in there, but it LOOKS like it may be pretty pitted and gray. I think too in the mix of things that bypass hot wire to the coil is a great way to "eliminate" the potential of a bad ignition switch. Maybe a ohmeter. Kinda of like thevenins theorum. Make it simple.

Thanks for your continued help

Thank you for your thoughtful insight into the problem. I am going to buy a point contact file and see if I can refurbish the regulator. If no luck, I found a man who sells U.S.A made regulators that I will purchase.

I will write more after I try the above.

Thanks