Author Topic: Startomatic Generator Rewind  (Read 15558 times)

jimboz

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Startomatic Generator Rewind
« on: January 18, 2014, 12:47:00 AM »
My new to me 8-1 startomatic seems to have a burned stator coil, is anyone aware of a rewind shop familiar with lister's combined DC/AC coils or is it something that any decent rewind shop could handle?

Thanks

listeroil

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Re: Startomatic Generator Rewind
« Reply #1 on: January 20, 2014, 09:42:58 PM »
I should think any decent rewind shop should be able to easily handle that job.

Heres a picture of the windings in question each held on with 2 bolts.





Mick

jimboz

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Re: Startomatic Generator Rewind
« Reply #2 on: January 21, 2014, 01:31:51 AM »
Yup, that looks just like mine, except mine's full of grease and one of my coils appears burned.  I'm thinking the combined DC and AC windings might throw a rewind shop for a loop, I'm going to do some calling tomorrow.

BTW, I have 3 pairs of brushes on the commutator, I'm guessing one set for excitation, one for generating and one for starting (motoring), is that right?

Also, looking at the unit from the slip ring end on the right side, there's a 1" diameter aluminum cylinder which has a post going through the comm brush holder assembly with a wire attached to each end of the cylinder, any idea what it is?

listeroil

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Re: Startomatic Generator Rewind
« Reply #3 on: January 21, 2014, 11:59:31 AM »
Jimboz

The stator windings are DC starting windings (SSW)  shunt field winding (SFW) and auxiliary field winding (AFW)
The 3 sets of brushes are as follows
The slipring brushes 20 x 8 x 20 are the AC output.
The 4 big brushes 3/8 x 3/8 x 1 are the start brushes and the DC output brushes.
The 2 small brushes 3/8 x 1/4 x 1 are the auxiliary field winding brushes they send power to the small resistor (Y) in the casing and to the aux field winding. They adjust the volts at high power.






The round can you are referring to is the interference suppressor and is a feed through device on the main AC output.  If its faulty it can be totally dispensed with and a nylon bush made like the one in this picture.





Mick

















jimboz

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Re: Startomatic Generator Rewind
« Reply #4 on: January 23, 2014, 12:30:32 AM »
Thought I'd give an update, spent the better part of the day cleaning grease and grime out of the generator, removed the brush holder assembly and was able to get a good read on each winding and it looks like all windings are good.  I wish I had a megger... maybe I'll be able to find one before rotation.  Thanks for the help so far.

tiger

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Re: Startomatic Generator Rewind
« Reply #5 on: January 23, 2014, 02:45:56 AM »
sounds good next I would either bake out or vacuum out any moisture. then apply a AC voltage thru a variac or light bulbs in series with a ampmeter, or any multimeter will do to each winding to  the housing. no current should be present. bake at 150 f for an hour or more first. more is better, you might have to send your wife out of town first! If you have a container big enough to seal and draw a vacuum and can pull 23 inches  for 24hrs that is best. one can apply a low voltage thru a transformer to heat up the individual coils to dry out the moisture. a lot of gen heads have this feature built in.
Metro 12/2 ST 10 KW

jimboz

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Re: Startomatic Generator Rewind
« Reply #6 on: January 23, 2014, 02:57:41 PM »
Tiger,

You're talking about the stator windings, right?  If so, why would you use AC and not DC, what voltage magnitude would you apply for the current check and the drying out process.  Would you do anything to the rotor windings?

Thanks,
Jim

jimboz

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Re: Startomatic Generator Rewind
« Reply #7 on: January 24, 2014, 01:54:17 AM »
Here's some picts of the rotor after cutting the comm and slip rings.  Notice how greasy the windings are... any recommendations on how to clean?












« Last Edit: January 24, 2014, 02:08:04 AM by jimboz »

tiger

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Re: Startomatic Generator Rewind
« Reply #8 on: January 24, 2014, 04:42:43 AM »
JIMBOZ: YOU can use either ac or dc on both stator and rotor keep the voltage low and work up to the windings normal working voltage by variac(AC)  or removing the lightbulbs as required,monitor the series connection with meter for current, there should be none when clean and dry to frame and low ohms thru  the windings themselves. The cleaner of choice for windings before the 70's was carbontetrachloride, next came trichlorethlyne both EPA no no's now. I would try CRC brake cleaner on a exposed small area and check that the insulating varnish does not desolve. some rewind shops will clean and reinsulate windings, but the results are questionable. In my case done after a salt water dunking the gen burned up after a year with low usage over that time. Good luck, the pics look pretty good!
Metro 12/2 ST 10 KW

jimboz

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Re: Startomatic Generator Rewind
« Reply #9 on: January 26, 2014, 09:51:13 PM »
After cleanup.  Now it will sit on the woodstove for a couple weeks.






Tiger, to check the insulation; I should take the hot lead of my power source, connect a couple lightbulbs in series and then connect to the winding, then put me meter on amps, put one lead on the frame/shaft and the other to the other side of my power source, right?  220VAC is the max I have available for the AC/slip ring circuit, what max voltage would you recommend for the DC and AC fields?

Thanks,

tiger

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Re: Startomatic Generator Rewind
« Reply #10 on: January 27, 2014, 01:59:54 AM »
you are correct in the hookup, one end of each coil to remain  not connected! we are trying to measure leakage current. Listeroils print shows both ac and dc tied to ground probably at frame at some point, make sure that is disconnected before test. start with meter at amps then go down to milli then- micro amps. as for test voltage work up to twice operating voltage,IE starter/ gen at 24volts test at 48 volts starting with meter at amps at each level. the test lamps will limit current if things go south, of course if they light at all there is a problem.If anything goes haywire shut down and dryout the winding  some more, then try again at lowest voltage level. Your pics are encouraging, a good eyeball on the visible windings can really help.
Metro 12/2 ST 10 KW

somian

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Re: Startomatic Generator Rewind
« Reply #11 on: January 27, 2014, 03:58:40 PM »
Even if the suppressor looks good I would get rid of it before it dies in a great cloud of evil smoke and possibly damages somat else doing so. It serves no useful purpose

Ian

listeroil

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Re: Startomatic Generator Rewind
« Reply #12 on: January 27, 2014, 07:36:07 PM »
Even if the suppressor looks good I would get rid of it before it dies in a great cloud of evil smoke and possibly damages somat else doing so. It serves no useful purpose

Ian

I would totally agree with this. They work fine without and cause no interference on modern equipment.

Mick

jimboz

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Re: Startomatic Generator Rewind
« Reply #13 on: January 29, 2014, 12:20:33 AM »
Anyone know what grade the startomatic brushes are?

Thanks,

Bottleveg

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Re: Startomatic Generator Rewind
« Reply #14 on: January 29, 2014, 12:45:51 AM »
Anyone know what grade the startomatic brushes are?

Thanks,

DC (4 brushes) CM6
DC (2 brushes) C4
AC SB5