D650 dynamo thingy

[cityfarma]

My previous comments where made not knowing the age of the tractor. They still apply but I would add that any generation device on a car/truck/tractor etc in the last 20yrs is more than likely to be an alternator as they are far smaller and efficient.

Cityfarma

 

[solwisestsve]

Age??? Who knows? ;-)

It's a referb. B6001. Anyone know when the B6001's were made? I'm going to guess at least 20 years old.

The generator has three wires going from it so that might meen it's a very small alternator. There's no traditional 'charging' light but I suppose it's possible this role could be controlled by the rectifier.

 

[cityfarma]

It may be a relay type regulator. They have two relays that (from memory) control voltage and current.

The voltage coil contacts are normally closed with the engine stopped. When the engine is started, current is applied to the field. The gen/alt then produces voltage and the relay operates if higher than the set voltage. This stops current flowing in the field and the voltage drops. This releases the relay and current flows again. The result is that the relay buzzes when regulating the voltage.

The current regulator is similar except that the gen/alt current flows through the coil of the relay. If the current exceeds the set current, the relay operates and cuts the current to the field. It also buzzes if the current is too high.

The regulation is adjusted by changing the distance that the contact arm is away from the relay pole. If the distance is greater, the higher the voltage or current required to operate the relay.

If you can post a picture of the gen/alt and regulator, it may be possible to identify it.

Cityfarma

 

[KubotainNH]

I just got the volt meter out to measure my B6100. The thing actually fluctuates alot. When off I read 12.46. After starting it the voltage actually drops but then after about a minute it starts to rise. At half throttle it started at 12.9v and rose to 14.5. Drop it back to idle and it drops down to 13v and keeps dropping depending on how low it is idling. High idle runs about 12.85. I've had the tractor for a couple years and never had an issue with a dead battery even if it sat for a month. The same battery is still in it from when I bought it. There's some pictures of mine on this post: http://www.tractorbynet.com/forums/kubota-owning-operating/70830-b6100-picture-3.html#post1208547 If it looks similar then it's most likely a dynamo.

 

[solwisestsve]

Sorry for the late reply... Been too busy of late.
Well your readings are exactly what I'd expect but, unfortunately, are NOT what I get :-(
Looks like I'm going to have to do some more stripping down and tracing :-( TBH just so blasted busy at the moment that it will just have to wait - sounds like a winter job ;-)

Thanks for your readings though, if nothing else they've confirmed I have something wrong.

I'll use the curcuit diagrame (previous post) and give it a good trace down and measure to try and find out exactly what's to blame - I just hope it's something easy to replace/fix.

On a similar note. I was looking around and I wonder if it would be possible to fit a very small car sourced alternator in the spot where the belt adjuster sits? Then I could rip out the recitfier and start from scratch with something more modern and that I understamnd a lot better

 

[cityfarma]

If you source an alternator and (inbuilt?) regulator you should be able to replace the generator. The interesting part would be fitting it.

Cityfarma

 

[KubotainNH]

I think it has been done and posted here for other models. Try the search function. Some models have a Kubota kit to upgrade it but no idea if this one does.

 

[David_Kb7uns]

The dynamo on my BX2230 put out AC current. The Kubota dynamo uses a magnet where the alternator that i replaced the dyanmo with uses a field that has a regulator to change its strength. They both put out AC current where a Generator puts out just DC. If you look at some of the schematics for the Kubota tractors the rectifier will send half of the AC wave to the lights and the other half is regulated for charging the battery, this is similar scheme done with the dual circuit charging on Briggs engines for riding lawn mowers.
David