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Forum Index : Windmills : Testing Capacitors

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fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 11:26am 05 Dec 2008
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Hi Gordon and everyone ,

Hopefully soon I should have a test bed set up for doing the performance tests with caps , I looked at setting a dual stator up direct into the lathe chuck but feel a little hesitant about the start being so quick , also the speeds do not give much away for low speed performance data [spindal speeds are 65 100 180 200 235 280 300 330 360 500 550 700 840 910 1095 1200 1400] .. This may be ok for initial tests but misses a lot between 60 to 275 rpm , so as time allows I wiil make a pulley drive that mounts into the chuck and mount the ststors into the gap bed with an idler that can slowly engauge the stators at 2:1 or whatever ratio is required .. Any thoughts are muchly appreciated

Edited by fillm 2008-12-06
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 12:14pm 05 Dec 2008
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Hi phill,

what about the thread cutting settings. These will surely be much lower speeds.

Gordon.

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Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904
Posted: 01:47pm 05 Dec 2008
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  GWatPE said   Hi phill,

what about the thread cutting settings. These will surely be much lower speeds.

Gordon.


I doubt it Gordon, the 65RPM setting would be used for thread cutting, slow enough IMO.

Klaus
 
oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686
Posted: 03:31pm 05 Dec 2008
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Phil,
Perfect setup for torque measurement you have there.

My lathe has a fluid clutch for slipping, which I don't suppose yours has from the sounds of it. (I have never used a clutchless machine... threading must be exciting). If that is the case, I would be inclined to use a live center to make certain it could not twist with the rapid startup. (don't know how much shaft you have in your chuck).

From the speeds you have available, you may get enough data to extrapolate reasonably.

If that lathe has a belt drive for the primary (motor to gearbox) drive, an over sized belt and idler there may give you the slip you desire, without building a complex drive after the chuck.

It would all work better if that machine was not so darn clean

Look forward to seeing you duplicate Gordons great results. If we can get a body of supporting evidence, then Caps may become more mainstream, and even Flux my take notice.

.........oztules
Village idiot...or... just another hack out of his depth
 
herbnz

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Joined: 18/02/2007
Location: New Zealand
Posts: 258
Posted: 10:19pm 05 Dec 2008
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Hi Phil
Pushed for time just now but I have used my lathe to test FP units both gentle annie and smart drives would love to test caps but have used my higher powered drive motor on my present project (driving piles for my jetty )
However some ideas that I have used over the years.
I couple/replace on to the fixed speed motor with a universal type motor ie electric drills, skill saws, these can be speed controlled with a variable ac or dc voltage . I actually have a large dc motor and a variac but many of the cheap drills actually have speed control built in.
over here there is a 800watt drill that I have seen for < $80.
Another member of this forum has set up and rather than use the torque arm he made a disc so that the spring balence is always acting at a tangent regardless of the travel in the balence.
For smart drives I have just taken th complete base including the bearings and merely held the shaft in the chuck there is a pic somewhere on this forum but no time to track down just now

Herb
 
fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 11:09am 06 Dec 2008
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Hi Oztules , Herb , Gordon ,
Thanks for the feed back , I know its early in the stages of setting this test up but welcome all input , the O/S belt is a great idea but my concern is being able to gather as much info at the lower speeds of up to 300rpm as different cut in speeds with different cap sizes might mean something . Of course seeing what the max output is also of interest , building the support to mount my dual of the gap bed mounts isn't that hard and enables quick ratio change by swaping a pulley mounted in the chuck . The lathe drive motor is 2Hp so a varible speed drive may be a bit expensive ?

As I am new to the use of caps , I am only feeding of what Gordon has achieved and hopefully with his help and all on the "Back Shed" is to get the set up correct to be able to put the data up for all to use

Herb , the spring balance , what are we mesuring is it ineffiency ? I have a spare JCar power meter and was going to have it on the lathe ac plug and then
1- Run lathe unloaded -
2- Run lathe with drive and bearing assy [no rotors]
3- Run lathe with rotors unloaded
4- Run with load [record output]
This sould give a power loss in watts/amps to power out watts/amps . Is this a fair test ?
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
herbnz

Senior Member

Joined: 18/02/2007
Location: New Zealand
Posts: 258
Posted: 05:35pm 06 Dec 2008
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Hi Phil

The use of measuring input by your method is inaccurate and prone to unforeen events that mask the results. I cannot read anything into the testing I see on this forum as either inputs are not stated or the way it is arrived at is very subjective, I suspect a lot of others are in a similar boat.
Using what I like to refer to as a dyno method (what Dinges calls a Pony test ) is direct and not masked by other variables. Also in the long run simpler.
It relies not mounting the stator directly but having a spring balence to measure the reaction this is input torque, a simple calculation gives input power.
Variable speed is desireable so fine adjustments can be made to repeat tests at identical speeds ie with caps without caps , so there is again no need to confuse the issue with graphs etc.
Herb
 
Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 894
Posted: 08:14pm 06 Dec 2008
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Hi Phill,
As you said your lathe is 2hp, why not stick a 3 phase motor on and throw a vfd on it Then you'll have variable speed from 1 rpm all the way up to the max your lathe can go. Forward/reverse, ramp down or brake on stopping. The best part is you an run ya lathe off your RE setup. For me being off grid those vfd's are the best thing since sliced bread allowing me to run my bridgeport and lathes in there full glory off my RE bank with no bloody loud genset in the background.

Just sing out if you want to go this route and I can get pricing for you.

Cheers Bryan
 
matt down south
Regular Member

Joined: 20/10/2007
Location: Australia
Posts: 50
Posted: 04:37am 07 Dec 2008
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hi Phil
i use a 5hp petrol stationaary motor off the dump shop for $10 with a 5 groove multistep pulley for testing with a multimeter set on frecency for the rev count its cheap variable and doesnt overload anything
matt
 
fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 11:27am 07 Dec 2008
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Hi Bryan , Matt ,

It would be great to have a variable speed 3 phase drive but for the moment I could not justify the cost to THE BOSS after buying a brand new lathe to play on , as well as the associated cost of running 3phase to the shed , I will have to do the best I can with what I have , but it sounds like you have a good set up for testing as well Bryan , why not do some testing as well to add data to this ?

I suppose a lot of us have various types of test set ups like Matt,Bryan,Herb and maybe we should all be pulling together as a team to test along the same general idea and [ TO MAKE OR F&Ps MORE EFFECIENT AT PRODUCING POWER ] and any test setup should be able to gather data ,either a vfd , small engine , read with multimeters or whatever meter or spring balance, the difference with using "caps " and without "caps" should become apparent and achieve an accross the board comparasion ....



PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
herbnz

Senior Member

Joined: 18/02/2007
Location: New Zealand
Posts: 258
Posted: 05:47pm 07 Dec 2008
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Phil
No need to run 3 Phase VFD on the market produce 3 phase from single phase I have 3 old ones here but cost freight etc not viable. For experimental uses I find the unversal motor temporaliy coupled to my lathe motor that i still leave in place but do not energise easiler to control.
Measuring input power is not done to arrive at efficiency but to get results that have meaning .
Herb
 
fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 11:46am 18 Dec 2008
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Hi All ,
Finnished the test rig for testing , I have taken Gordons and Herbs advise and built it so the torque arm between the dual stators can be rigged with a spring scale or I was thinking of a set of digital kitchen scales and a roller bearing on the end to push on the scales , I have drilled a couple of holes in the arm to allow the arm extension to go on later as I am not sure what length to have it .

The reduction of the lathe is 1.6:1 and I have a larger pulley to use that will probably be 2.8:1 so I should be able to cover a fair range of speeds below 400rpm .

Hopefully as stated , with the mesurement of the torque , the tests will not be masked by other variables ...






As you can see I have used one of my dual bearing housing to allow the whole dual stator to be floating , of course the test does not have to be a dual as one stator can be removed . I was running it today at no load , no declogging and the small 200g scales I have were reading 170g @ 40rpm , as I do not know the caculations for the HP or watts at a certain length I will leave that to be informed of through the forum as I am sure someone will know and will be able to give a standard torque arm length .. Regards ..
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 12:22pm 18 Dec 2008
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Hi Phill,

you have been spending too much time at Bruces. Too clean for me and all that fresh paint. Only kidding!

Great job.

Need a cheap source of caps now, for a decent range of testing combinations. May be useful to confirm some predictions first though.

Gordon.
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SparWeb

Senior Member

Joined: 17/04/2008
Location: Canada
Posts: 195
Posted: 04:08pm 18 Dec 2008
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A test fixture that's painted... Never seen that before!

Looking forward to test results, particularly when the data is collected as carefully as the construction of the rig.

Steven T. Fahey
 
KiwiJohn
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Joined: 01/12/2005
Location: New Zealand
Posts: 691
Posted: 11:01pm 18 Dec 2008
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Phil, I believe torque is length of the arm times the 'weight' you measure. Horsepower is torque times RPM. Horsepower is directly convertable to Watts. Without the length of the arm I cant calculate anything interesting from your 40rpm example.

I suggest if you want to use heavy weight scales you would choose a short lever length, but if you have the room and want to make the calculations easy a lever of 1 metre would be a good choice. I think if you want accuracy you would have to balance the stator assembly so that at 0rpm the scales reads "0".

If suitable scales is a problem I suppose you could use a long arm with a sliding weight on it but you would have to run the lathe in reverse (I think) and you would need to put limits on the arm so as to avoid accidents.

Nice looking test rig. Edited by KiwiJohn 2008-12-20
 
herbnz

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Joined: 18/02/2007
Location: New Zealand
Posts: 258
Posted: 11:22pm 18 Dec 2008
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Phil

Great setup

Ok Torque is Force (Kg ) * length to the attachment point scales from shaft centre (metres ) * 9.81

this is Newton Metres
The scales must act a right angle to the effective arm to the shaft centre.

Power in = 2 * pi (3.142) *N (rpm ) * T ( Newton metres from above) / 60

This gives Input in watts


Hope this makes sense

Herb
Ps

If I assume your arm is 150mm
Torque = .17 *.15 * 9.81 = .252
Watts = 2 *3.142 * 40 * .252 / 60 = 1.05 watts Edited by herbnz 2008-12-20
 
Dinges
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Joined: 04/01/2008
Location: Albania
Posts: 510
Posted: 04:02am 19 Dec 2008
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That's indeed a nice looking test rig. It's always a pleasure to look at such craftmanship, built with pride. I've seen finished windmills that were built to lower standards than your temporary test rig.

As for how to calculate mechanical power, HerbNZ is correct but it can be simplified even more:

P = 1.05 * W * l * n

with
P= mechanical input power [W]
W= weight readout of the scales [kg]
l= length of arm [m]
n= RPM

(More details can be found here: http://www.thebackshed.com/Windmill/FORUM1/forum_posts.asp?T ID=1246&PN=6)

It's just a matter of plugging the right values in that single equation and the correct numbers should roll out, using your favourite electronic sliderule.

Succes,

Peter.Edited by Dinges 2008-12-20
 
fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 10:55am 19 Dec 2008
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Hi All ,
Well first of thanks for the tick of approval on the test rigg , amazing what a quick hit of spray paint can hide . But as it is now built, and that was the easy part , I must say that using the torque arm is definatly the way to go , so thanks for pointing me in the right direction even though I had a couple of head scratching times before the light turned on and then it only took an afternoon to knock up .

I suppose now comes the hard part and setting up to start testing and of course getting a collection of caps and meters able to test the various configurations at different voltages .
I have 8 large 12v cat batteries that have been sitting arround for a while , hopefully they are in good enough condition to use .
From talking to Gordon , what I can make out is that different cap sizes have sweet spots at differing voltages and rpms , can something be set up to say : eg run at a set rpm with a set of caps and then vary the voltage laod on the stator from 12V to 60V and be able to watch the amp output [ I suppose that would be the load on the scales ] . I would think at a certain voltage at a set rpm when everything is correct and the cap is correctly loading you would get a spike in the load on the scales , I may be way of the mark but it's just a thought on how to work out where the cap performs best at..
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 11:27am 19 Dec 2008
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Hi Phill,

I would use the PV edge for the loading, starting at the lowest rpm, and working up for different cap sizes, and measuring the torque, for power in and the power to the load, with the AC power meter you have. You might just measure the DC voltage and current on the battery as well, for a comparison. The PV edge is at least 95% efficient at the 200W power level. No point in wasting the power in a resistor, that does not represent the load you will be using.

The power in and the rpm can be used for comparisons to a wind power curve.

Gordon.


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fillm

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Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 12:18pm 19 Dec 2008
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The only problem is the distance the Lathe is from the PVE Edge is a good 30mtrs, as you have seen and also being able to read the output on the AC power meter at the same time , I think I need to be able to read everything in the shed near the test rigg , I will just have to waste the test power produced as going to a good cause .
The variable voltage was a stab in the dark and I may just have to be swapping voltages with the battery bank and discharging them with the 600amp carbon pile load tester , $2.00 in power is the cheap bit , the caps are going to be the expensive part , I wish I still lived near my old dump I could scavange ...
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
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