squealing noise at startup

[Kelvin]

Good to hear that you're not having any problems.

You say that your tractor has no alternator. There is what I've heard called a "pulse alternator" attached to the back of your fan. I believe that you called it a "fan/magneto". Whatever you call it, that is what charges your battery.

What your tractor doesn't have is a water pump or thermostat (check out all the posts on "thermo-siphon" cooling").

One Idea: I don't know what kind of a draw that the "alternator or fan/magneto" has on startup, but it may be that your battery is more fully charged now than it was a few weeks ago. You may try a start attempt without pre-heat so that you run your battery down a bit. Then pre-heat and start the engine to see if it squeals when you start it up. In any event, make a mental note of the battery condition the next time you hear it squeal.

Kelvin

 

[Kelvin]

I decided to go to the shop manual and look up the alternator answer (to have or not to have...).

My shop manual covers the B5100 (D&E), B6100 (D,E, HST-E & HST-D)and the B7100 (D,E, HST-E & HST-D). The following statements come from the manual:

Cooling system (All Models):
All engines are liquid cooled and use a thermo-siphon cooling type cooling system. Note that the cooling fan (1-fig.34) is mounted on alternator. Recommended pressure rating for radiator cap is 88.25 kPa (13 psi). Recommended fan belt deflectioin under a load of 98 N (22 lbs) applied mid-point between fan pulley and tension pulley should be 10mm (25/64 inch). Relocate tension pulley to obtain desired belt tension.

Electrical System: Anternator (All models):
Alternator is mounted on water outlet and drives cooling fan. Refer to figure... Alternator should produce 14 volts maximum with a minimum charging current of 8 1/2 amperes at alternator speed of 4250 rpm.

Hope this helps clear up any confusion.

 

[RickM]

Hi Kelvin,
Thanks for your input. I am aware that my tractor uses the thermo-siphon cooling system. I keep my radiator and screen washed out religiously. Like you I opened up my operators manual, but found it calls my charging device a generator. I also have a copy of the electrical schematic provided by my dealer from his shop manuals at it calls my charging device an AC dynamo. My B6100 is of early '80's vintage. I used to know the difference between an alternator and a generator, but I can't seem to recall what is is now. I'm not sure if dynamo is synonymous with generator. I'm not sure why I used the term magneto, except it is what sprang to mind while I was posting. Seems I'm not sure about a lot these days /w3tcompact/icons/crazy.gif!

 

[Kelvin]

Hi RickM,
I guess that I found it a little hard to believe that if the SHOP manual calls the charging device an "alternator", that the OPERATOR'S manual would call it a "generator" but sure enough, mine does too (it took a long time to find it but finally found it on the wiring schematic in the back of the manual).

I too have a hard time recalling the difference between a generator and an alternator. There's room for error here, but I vaguely recall that a generator produces DC current and an alternator produces AC current (and converts it to DC). Nonetheless, I do remember that a generator is huge relative to the size of an alternator. I would therefore guess that we have an alternator on our B6100s and B7100s (my B7100 is a late '70s or possibly an early '80s model).

Anyone else is welcome to join in on this conversation and solve the "generator vs alternator" mystery.

PS I notice from your attached picture that you appear to not have a ROPS. Kubota dealers sell them relatively cheap (below $200 then add tax & shipping) and they are pretty easy to install (with two helpers).

 

[Bird]

Fellows, I can usually do my own troubleshooting and repairing of charging systems, but darned if I'd know how to explain the differences in them. One thing I never forgot was a sales meeting, when alternators first came out on cars, in which the instructor told the mechanics, "I know a lot of you are used to shorting across the terminals on a generator to see if you get a spark to tell whether it's working. Well, you can do that to an alternator, too, and if you get a spark you know it was working before you did that."

My shop manual for the B2710 says the charging system "consists of a AC dynamo and a regulator. The dynamo is an 8-8 pole rotating magnet type generator. It is simple in construction, consisting of a stator and rotor. The rotor is made up of eight permanent magnet pole pieces assembled on a shaft and rotates on the center of the stator around which eight electromagnetic coils are provided for. This dynamo produces higher voltage in slow speed rotation, and charges electric current to the battery during engine idling." I think (not sure) that the B7100 was the same.

Bird

 

[scruffy]

Kelvin, you are 100% correct on your AC=Alternator, and DC=Generator output. You can use an Alternator direct production of A.C. Current, of course you will want to regulate that output to a usable storage medium, ie the battery. (A little off the subject) By using waterpresure through a hose, downhill from a springbox, you can direct it a 'propeller' if you will, connected to an alternator and produce A.C. current as an alternate energy source. By running it to deep cycle batteries, you can power your home 24 hours a day. Cheap energy! it can also be hooked to a windmill for the same effect, although less continuous.

 

[TomG]

I remember letting a bar of hand soap rub on the fan belt of a car to make the belt squeal go away (That doesn't cure a problem of course). However, that might be a way of eliminating belts as a source of the squeal if it starts happening regularly.