First conversion Flyin!!!!

[wildbill hickup]

Well the old Ametek has been flyin for just about a year now and it has preformed well on a 7.5 volt NiCd battery bank running some LED's for my stairs.

But it's time to retire it and replace with the conversion I've been working on.

I won't go into a lot of details on the motor as they are listed in other posts. How ever here are some wind-time figures on the output of the new conversion, and an observation/question about them. All readings taken connected to a single 12v battery with both a revised LED system (for 12 volts) and a 12 headlight for a load.

Cutin speed seems to be about 7 MPH at which point I get .5 amp., 10 MPH 1 amp., 15 MPH 2 amps, 20 MPH 3 amps., there were some rally strong winds the other night and I would have loved to get some readings, but it was really nasty (snowing) and I was out plowing most of the night, so I couldn't. However on driving by the house a couple of times, that thing was really cranking. The yellow spokes (from the back) was just a yellow disk in the headlights. I did have it hooked to a partially drained car battery (about 10.5 volts) and it brought it up to full charge in about 5 or 6 hours.

Here are a couple of shots of the components of the alt. 1/2 hp four pole (3 mags per pole) 1750 RPM induction motor.

 

My thanks to TomW for the donation of the blades (I told you I'd use um) Jerry and Zubbly and all the others on the board for the help and info provided. This board is the greatest!!!!!!

Now to the observation/question!

At low wind speed/rotation both the voltage and amperage readings fluctuate quite a bit from say 0 to 10v and 0 to 700-800ma then it smooths out and gets a good reading. Does this sound normal for a four pole conversion or is something wrong? It was quite difficult to get all 3 mags into 1 pole (so the pole was exactly the same with) but I did get them very close. Could the slight difference in pole with be what is causing that fluctuation?

Again thanks to all

Wildbill

P.S. Sorry about the blury pictures(got to get a new camera) and yes that's the old tail repainted.

[TomW]

Bill;

Glad to see you put those blades to good use. Always rather see stuff in use than on a shelf. I always thought the "Jerry Blades" were a pretty good match for a unit that size like a TDM.

See you on IRC again one of these days.

Cheers.

TomW

[johnlm]

Bill,

Ive noticed the same issue regarding the fluctuation of DC output voltage at low currents when loaded with a resistive load.  The AC output voltage (before rectification) seems more stable but sometimes I see the dc measurement bouncing around about a half a volt or so.  If you put a large electrolitic cap on the dc output it settles down so my thoughs were that the digital voltmeter was just picking up the ripple on the output.  Without a filter cap the dc output on a single phase rectified waveform actually goes down to near 0 volts for a short period of time, and the digital meters start picking this up.  The old analog meters were so slow responding that they smoothed out this effect.  Im not exactly sure why the effect is less pronounced at higher loading.

John

[picmacmillan]

nice job wildbill...the more i read you guys post, the more i want to try a conversion....glad you got a new one flying, may it bring you lots of free electricity....pickster,...now get out there and get that snow shovelled!

[Dave B]

I'm no expert but I think it's the lower frequency that's causing "bumpy" DC and your meter can't keep up or ever freeze one reading. A capacitor across the output dampens the effect and smooths out the

DC voltage as does a faster rpm. Just my thoughts, Dave B.