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#120641 - 04/27/05 02:04 PM Home-built alternator & Some renovated machines
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Thanks to Alan Belson for the following:
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Home-built 3 phase Alternator and some renovated machines.

View workshop & long-house, ( built 1669 ) - 415v 3 phase + N supply only 20ft away, but PoCo wanted US $1800 to run a feed down the concrete pole & fit a new meter



6kva 400v 3-phase self-regulating alternator. 2 tandem 3hp motors 4" vee-pulleys- guards being built.. Wired Wye, neutral center to ground, Due to motor slip, I'm getting c. 390v at c 48hz.




Renovated "Copeau" bandsaw, c.1930. All original parts including motor. New carbide blade, 14 ½" depth of cut, 26 ½" throat.. Original 3" flat belt drive replaced with grafted on glass-fiber vee-pulley. Motor 5hp, 415v, 6 pole 970rpm rated, ventilated.








[This message has been edited by pauluk (edited 04-27-2005).]

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#120642 - 04/27/05 02:06 PM Re: Home-built alternator & Some renovated machines
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
1959 Robinson jointer / thicknesser ( 20" x 9" ). 5hp 415v 3 phase 2 pole 3000 rpm. On the bed is a home made 'chip-smasher'- 240v ½ hp 1470 rpm to break up the long shavings of walnut or cherry, they clog up the extract pipe - shavings go through a 9" diameter centrifugal rotor, and emerge as sawdust.



1930s foot-treadle operated machinist?s lathe found in England. Only tried pedalling it once, then I fitted a salvaged 240v ¼ hp 1450 rpm motor.




My horrible wiring. Catenary via 500ma rcd/40A breaker. Shop breakers via 30ma rcd. 25A shop power, 6A lights. Alternator s/ph motors fed through 16A breakers, 1 for each motor, Individual NVR starters used in sequence. RCD outlet is a supply for my wife's electric garden tools. 3 phase breakers linked 10A




Very useful 100+ year old Model 104 American speed indicator for motors/machines. "L S Starrett Athol Mass USA" Patented April 13 1897. Made before 1905 when another patent was taken. To use, point is applied to shaft centre and a stop-watch is run for 60 seconds, then read off the rpm. . Originally nickel plated, Starrett still make these.



Alan



[This message has been edited by pauluk (edited 04-27-2005).]

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#120643 - 04/28/05 09:26 AM Re: Home-built alternator & Some renovated machines
Texas_Ranger Offline
Member

Registered: 12/17/01
Posts: 2343
Loc: Vienna, Austria
Wow!!!
I love old stuff like that!
The gear reminds me of the stuff we have in some workshops at school. All old 380V gear, some of the machines are supposed to be from the 1950ies. The newest gear dates from 1983...

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#120644 - 04/28/05 03:13 PM Re: Home-built alternator & Some renovated machines
gideonr Offline
Member

Registered: 12/18/04
Posts: 152
Loc: Edinburgh, Scotland, UK
You could turn the middle pulley down a little smaller on the metalworking lathe to overcome the underrun.

Any ideas on how to get that kind of belt to stop vibrating? My dad's cast iron table saw came through the workshop fire intact, well the cast iron did, so I'm putting a new motor and pulleys on it. Trouble is the belt won't stop vibrating wildly. Any ideas?

Gideon.

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#120645 - 04/28/05 04:13 PM Re: Home-built alternator & Some renovated machines
Alan Belson Offline
Member

Registered: 03/23/05
Posts: 1801
Loc: Mayenne N. France
I had exactly the same problem at first. The unit was originally mounted on a timber chassis on those cedar brackets you see on the wall, which is actually the 2" thick oak boards of the original barn, now sheathed outside in California Redwood, but that's another story. The noise in the shop was like being inside a guitar! It only affected one belt- which proved to be nadgered (permanent twist through long storage in a plait). This is what you need to do to get a good long life vee-drive:-
Use a new belt(s), make sure pulleys are in good order & run true on diameter and are in line; use a straight edge over the pulley faces. Get the correct tension. Find distance between pulley centres & divide by 64. So a 16" (400mm) centre distance would give 1/4"(6mm). At the right adjustment, you should be able to depress the belt at its center by that amount with a hard push with your thumb. DON'T pry the belt on with a screwdriver, you'll damage the cords, or worse damage the pulley rim, especially cast iron. Fit it loose and then adjust the motor (or w.h.y. device) to the correct tension. I used oak wedges and fitted bolts as it's a home-brew.
Run the machine, and after say 24 use-hours, when bedding in will have occured, recheck/reset the tension. Make sure everything is tight- but not to the point of breaking the bolts! If the belt flanks or the pulley bottom(s) look very shiny- they're worn out.
If it still vibrates- suspect fire-damage to layshaft or saw bearings.
Hope this helps,
Alan
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Wood work but can't!

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#120646 - 04/28/05 07:41 PM Re: Home-built alternator & Some renovated machines
SolarPowered Offline
Member

Registered: 07/05/04
Posts: 615
Loc: Palo Alto, CA, USA
I had fantastic results on my table saw replacing the stock, cast-iron pulleys and belt with machined pulleys and a LinkBelt. (A LinkBelt is a strange-looking contraption consisting of red sections about an inch or so long, linked together.) There was significant vibration before the change; after the change, you can stand a nickel on its edge while the saw is running.

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#120647 - 04/29/05 02:09 AM Re: Home-built alternator & Some renovated machines
Alan Belson Offline
Member

Registered: 03/23/05
Posts: 1801
Loc: Mayenne N. France
I thought about that linked belt, it had good write ups and seemed the answer, as I have a lot of vee-belting. 'Fenner' sell this in the UK. It comes,I think, in 10 or 25 metres packs.
Wait till you see the price per metre, I think it was over £350 a pack. I just couldn't get it past Accounts- ( aka Her Indoors!)
Alan
_________________________
Wood work but can't!

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#120648 - 04/29/05 02:56 AM Re: Home-built alternator & Some renovated machines
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Wow Alan!,
Thanks a bunch for them pics (and to Paul for posting them).
I could look at pictures like this for hours.
Oddly enough I know for a fact that there is an RPM meter of the exact type that you posted above in the Electrical Store (read: museum) at Pareora Freezing Works, south of here, I've used it before.
I may show my ignorance/lack of knowledge here, but why did you go for 2 motors driving the Alternator?.
Oh and BTW Alan, good to see you've got a Fire Extinguisher there, essential equipment in any workshop worthy of the name.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#120649 - 04/29/05 05:38 AM Re: Home-built alternator & Some renovated machines
Alan Belson Offline
Member

Registered: 03/23/05
Posts: 1801
Loc: Mayenne N. France
Trumpy, thanks for the comments.
Those 'Starrett' speed meters appear on E-bay auctions regularly -mint 1905 onwards models seem to go for only US$10-20, and are a boon for analysing induction motor performance, (ie find slip,frequency). Hard to use at first, as you know, co-ordinating beween the stopwatch and engage/disengage, but I average over a few goes.
I chose 2 motors for several reasons: Firstly I'm on the end of the power-line, as you can see, and have a real problem with volts drop- I never get more than 227v, less when all the district milking-machines start up! This limits the amps I can draw-I only have 40A to the shop. If you calculate 4A/hp sph ind. motor start without load, I'd need at least 24A to start the Alternator even on full 240 volts, and you khow what happens to Amps when volts sag.... So by starting the set on one motor, part load, I draw 16A or less. Once she's running, I fire No 2. Also, I had one 3hp-motor already, and 3rdly a 6hp sph. ind. motor is a rare beast here. Even with the set up shown, all the fluorescents drop out on start, and I've put in a few tungsten bulbs so's not to be plunged into darkness. I'm not pushing the alternator to its capacity- I reckon I could put 2x4hp motors on, if 'her-indoors' sanctioned it, but my mate from Perkins is now looking out for a small electric-start diesel, say out of a digger. Then I can run the big panel saw on 3ph too; I've got the motor- Felder sold me a sph motor replacement when I renovated it, but it's underpowered. The fire extinguishers are a must. In fact the shop has three, which aren't all shown in the pics. Shavings are a real fire hazard, and I've got a wood stove....
Alan
_________________________
Wood work but can't!

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#120650 - 05/16/05 12:48 PM Re: Home-built alternator & Some renovated machines
mxslick Offline
Member

Registered: 10/24/04
Posts: 785
Loc: Atomic City, ID USA
Alan:

Great setup and ingenious solution to the singe/3ph. conversion problem!!

 Quote:
6kva 400v 3-phase self-regulating alternator. 2 tandem 3hp motors 4" vee-pulleys- guards being built.. Wired Wye, neutral center to ground, Due to motor slip, I'm getting c. 390v at c 48hz.


If I'm not mistaken, if you were to increase the motor pullys diameter a bit (or decrease the alternator's pully size) wouldn't that correct for the motor's slip and bring the output back up to spec? Staying within the RPM limit of the alternator of course.
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