Baldor 3 HP Motor Conversion Test Run

[SparWeb]

Over the weekend I spent tme at the office (boo) using the shop to test my new genny (yay).

I took a few pictures, and I borrowed a camera that takes videos, so I decided to try YouTube:

http://www.youtube.com/watch?v=604dgSMzvu8  Test Set-up explanation - mechanical parts

http://www.youtube.com/watch?v=baOZut11B2E  Test Set-up explanation - electrical parts

http://www.youtube.com/watch?v=RXq4k1FcXcw  Running at low power (80W)

http://www.youtube.com/watch?v=NV1YZ_9pBT4  Running at high power (780W)

http://www.youtube.com/watch?v=oVGgkqSp23w  Running fast + open circuit (101 volts)

YouTube jumbles up all my videos, so I hope people can find things using these links instead.  I also added captions - it "mostly"
worked and the I had to edit a bunch of mumbly jumbly words that didn't make sense.  Maybe I shouldn't have bothered!

I also had to crunch the numbers a bit, but this went quickly since I kept my spreadsheet from testing my Toshiba conversion.

The results are in and  I AM TOTALLY THRILLED  I really didn't think it would do so well!







Forty amps - golly!

Some may want to comment on how similar the curves are for the different connection schemes.  I was surprised by this, too. 
They sit in the expected places on the efficiency graph, but there isn't much difference on the others, is there?

Rough calcs tell me that a 10-foot diameter prop is a minimum with this much power load.  This genny is also much more "stiff"
than others I've built, meaning it may have the ability to stall the blades in high winds.  (Motor conversions typically don't do that).

[ruddycrazy]

Hi Steven,
               Great set of u-tube vid's mate and personally I can see where a total rewind is the go on doing motor conversions. When I get my dual axial flux genny made my 2hp motor conversion will be back in the shop for a rewind as it only has the original wire in and the best I see in most conditions is 300 watts at best.

Well Done

Cheers Bryan

[TomW]

Spar;

Nice bit of interesting graphing (no BW for youtube here in the sticks)

Just a friendly poke:

Is it paralel or parallel?

Sorry couldn't resist as you tried both.

Seems Mark Twain commented " I don 't give a damn for a man that can only spell a word one way. "

All in good fun.

Tom

[SparWeb]

Bryan,
Then maybe you'd be surprised to learn that I haven't re-wound this one?
The stock winding is so well done, it almost makes no sense to cut it out.
I did cut apart the star point to run out wires 10, 11, and 12, but that's it!

Not all motors are created equal.  My first conversion, also a 3HP 3-phase motor, never delivered more than 700 watts.  I put 12 cubic inches of magnet on the rotor.
The next was a 7.5 HP motor, 24 cubic inches of mags, got 1100 Watts in run-up test.  The next, pitiful looking but rated at 5HP, I put 12 cubic inches and it struggles to get over 300W.  This one has 18 cubic inches of mag, was rated at 3HP, and I saw 1200 Watts before I had to quit for the sake of the driving lathe, not the motor!

So my experience suggests that it is the combination of 1) a motor of quality construction to begin with,  2) as much magnet on the rotor as can be fit, 3) as little gap between mag and stator as possible.

[SparWeb]

Tom,

I'll get some pictures cropped for safe fieldlines viewing soon - I haven't forgotten about you.
U-Tub is time-consuming - time wasting from some people's point of view.

[SparWeb]

Okay, got the pictures sized properly.

I hauled a whole bunch of batteries with me, and I wired up that board in advance so I wouldn't piss around while at work.  The planning paid off because I got in, did all the tests, and packed out in 5 hours.  I brought my old Wattmeter with me, and it was indispensable.  It's much simpler just reading off that steady needle than trying to decide with of the 3 decimal places to keep on a DMM.  Speaking of DMM's, they actually agreed with each other most of the time, a nice surprise.  Just to illustrate and have fun, I ran the current (about 40 amps) through a thin piece of wire (last picture) and made it glow nicely!

The reason for all this stuff is so that I can measure both the input torque and RPM.  With those figures I have the input power.  With the wattmeter on the output side, the analysis gets pretty simple: efficiency is power_out divided by power_in.

All of the tests used 24V batteries.  Maybe I could have tried 48V but I can't contemplate a 48V system at home right now, so it would be totally academic.  The goal of the tests was to size up the prop, and identify the preferred connection scheme for the generator.  I don't know if everyone would agree, but I'm leaning toward Jerry (individually rectifying the phases).

[TomW]

Spar;

Entirely too neat to be actual tests. You must have photoshopped that all up



Tom

[ghurd]

Great writeup!

Very interesting.
I am astounded the charts show all 3 configurations so close together.  Do you figure it could be related to the 'stiffness'?


It looks too neat to be accurate, like Tom said.
I never consider it to be a real or thorough test until something catches on fire.   Twice.
G-

[TomW]

Spar;

Glen asked me how many HD magnets this bad boy would take to convert:



How would you suggest a person would do it?

It is a 3 phase and a puny 100HP

Tom

[SparWeb]

...how many HD magnets this bad boy would take to convert

I dunno - ask the guy who collected all these!

[hiker]

hey SPARWEB..
any picts on your rotor?......
the only way i reached 100 volts out was with all six wires in series.. or 60v open for each 4 coils..[with my 3hp single phase motor]
just using a hand drill for now--once i hook it to to one of my pedgens i should see higher voltage and power out...
for now thou with my drill at a slow speed it lites up a 50 watt 12v headlite easy--by hand a little harder..
any way im impressed with the power output useing the mags i installed..96 mags.....
hmmm....wounder if i could lite up the 1000 watt side of my 28v aircraft lite..shoulsd be able to lite up the 400 watt side !

[hiker]

found your rotor picts......
nice set up..........i used jb weld on my mags--didnt really see any loss in magnatizem--with or without the jb weld...
still have a few kinks to work out..might try the pedgen test tomorrow............