Author Topic: Start-o-matic alternator :(  (Read 5876 times)

AdeV73

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Start-o-matic alternator :(
« on: September 09, 2009, 12:33:48 PM »
I've just been told by a former alternator winder that my S-o-M alternator is beyond economic repair (requires a rewind). Obviously, this is a bit of a blow, as I was hoping to make at least one of my engines an "as original as possible" piece, either for sale, or just for me to fawn over.

Sadly, that's not to be.

So... it looks like both motors will get to do useful work instead :) Now that I seem to be acquiring 3-phase machinery, I think I'd like a 3-phase alternator. Any recommendations from the panel? Engine is a 6/1 original Lister, I will also be harvesting waste heat from both exhaust & water jacket, and running on veg oil (not yet, though, one step at a time...), I don't mind over-sizing the alternator a little (better slightly oversized than under). I also don't mind using a 3-phase motor as an alternator, if that's the most practical low-cost solution. Control electronics are not a problem - what I can't do myself, I have a Man Who Can available to me. Similarly, for making a safe 3-ph installation, I know an excellent electrician who works for little more than beer money.

(edit: I should probably point out that I'm currently based in the UK, which probably rules out any US equipment, due to shipping costs)
« Last Edit: September 09, 2009, 12:36:14 PM by AdeV »

compig

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Re: Start-o-matic alternator :(
« Reply #1 on: September 09, 2009, 12:48:29 PM »
Bad luck Ade :(  First thought on trying to use a 3 phase alternator is you will struggle to find a small one and 2.5 KW is not much use in 3 phase. Lister SOM alternators do sometimes appear on epay. Also , what exactly constitutes 'beyond economic repair' in your mans eyes ?
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jzeeff

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Re: Start-o-matic alternator :(
« Reply #2 on: September 09, 2009, 01:23:43 PM »

I would just buy a variable speed drive - VSD to create 3phase from 1.  They are very inexpensive now -  plus variable speed can be useful and starting loads are lower.




AdeV73

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Re: Start-o-matic alternator :(
« Reply #3 on: September 09, 2009, 02:54:10 PM »
Bad luck Ade :(  First thought on trying to use a 3 phase alternator is you will struggle to find a small one and 2.5 KW is not much use in 3 phase. Lister SOM alternators do sometimes appear on epay. Also , what exactly constitutes 'beyond economic repair' in your mans eyes ?

BER = it requires a full re-wind, apparently, which will take several days at a cost of £lots. OK, the bloke who guestimated it is a bit of a muppet, but he claimed he'd quote 2 weeks to do the job, on the basis it would probably take a bit over 1 week to actually do. Now, that seems a little excessive to me (40+ hours to re-wind?), although as there's no pattern to go on, other than the current machine, I must admit it's not something I'd be willing to take on.

Anyway, before it gets re-wound, there's the issue of that bent shaft. And the worn bushes /slip rings. The damage to the back of the alternator (it's taken quite a tumble at some time in its life). Even then, there's no guarantee that the selenium rectifier will work, or - indeed - that any of the rest of the electric stuff is OK.

I could have dealt with pretty much anything, except for a rewind frankly. I'm not ready to tackle that size of job...


I would just buy a variable speed drive - VSD to create 3phase from 1.  They are very inexpensive now -  plus variable speed can be useful and starting loads are lower.


For sure, that's an option. I may also consider a line shaft, which with suitable gearing I could turn both a lathe & the mill without incurring any electrical losses (at the cost of an emergency stop button, for sure). The power feed & DRO on the mill could be fed 110v from a small alternator...

rl71459

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Re: Start-o-matic alternator :(
« Reply #4 on: September 09, 2009, 05:10:15 PM »
In regard to VFD's... Yes they are getting inexpensive. But it all depends upon what you need to do... If you have a machine
that has multiple 3 phase motors that need powering it may not be practical. or if you have multiple machines.

I have applied my share of VFD's with good results, But sometimes it is more suitable to take another approach due to cost
or required rewiring of the machine. Also note that it sometimes is misleading looking at drive cost's because not all drives are
configured the same and many times the needed items to properly complete the install are not included in the initial purchase cost.

Please do not take this as a deterent to an application that is well suited for a VFD because they work great for many things.

My .02 cents
Rob

mobile_bob

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Re: Start-o-matic alternator :(
« Reply #5 on: September 09, 2009, 08:48:06 PM »
if i were you i would ask around for any oldtimers that have retired from the rewind shops in your area, or expanded
area.
often times these men could use the extra cash, and are looking for something to do anyway for various reasons.
coming up on winter months means they can't be dinking around the garden and will be stuck with the old lady
all day,,, perfect time for a project to get them out of "her" house anyway.

i am sure it is a time consuming process, but can't imagine it takeing 40 hrs to rewind, a good winder could sketch up the
type and number of windings, turn count etc surely in a half day and have time for tea and a nap or two.
then another half day to strip the field and armature, followed by cleaning up the cores.

so maybe he has to make up some wooden coil formers, bet he has done that so many times over the years he could do
it in his sleep anyway,, so give him a half day for that

outside maybe 3-4 days tops, and likely a bit better than than unless is wife has him doing honey do's along the way.

the thing is, there are other SOM around that will need rewind at some point, find the right retired guy and he has a ready made
part time deal where he can make some bucks and guys can get their generators rewound.

its a win/win situation.

ask around i bet you can find just the guy

the problem with shops these days is they have been busy so long during good times rewinding modern stuff, where they can
find all the documentation direct from the manufacture or even get the prewound coils from the oem
this speeds the process, all they have to do is burn out and strip the cores, clean/paint and reassemble  the thing

i bet if they had all the spec's on your genhead they could probably rewind it in a couple days no problem.
even though it would be still expensive it would be about half the time of what it would be as a one off oddball
with no documentation that no one still living there even remotely remembers.

ask around, you might get lucky

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info