Author Topic: Baldour motor conversion (Read 9345 times)

Spdlmt150 · « **on:** February 02, 2007, 05:51:23 AM »

Since I had it available.... I decided to do a conversion on a Baldour 1/2 horse 1725RPM motor. After tinkering with the lakewood box fan, I decided to go for something that might actually provide me with a useable amount of amperage.

The motor as it started out....

I figured the skew at 5.5 degrees. I haven't yet figured out a way to draw it. What it ended up being was 1.875 degrees between magnets, 5.625 degrees from end to end. Each pole is 3 rows.

After figuring all the dimensions, the armature was turned down, and milled with 48 flats to mount the magnets. The mags are 1/2" X 1/2" X 1/4"

The magnets were mounted with Loctite super glue to hold them while the assembly was poured.

My high tech method of pouring an armature. I find a container slightly larger than the assembly. Poke a hole to let the shaft come through it. Epoxy the face of the armature to the bottom of the container. Pour. Wait. Wait. Wait. Remove. Turn down to size. So far it has worked quite well for me.

When I removed the shaft from the container it was still quite sticky. A pair of 100w light bulbs warmed it up nicely & finished curing.

After it hardened up it went in to work to get turned down to size. I also pressed the bearings on. I couldn't have been happier with how it turned out.

I did remove all of the wiring for the thermal switch & capacitor. This left me with six leads coming out of the can. Wired in star I am seeing 4.5 ohms, 27.5 volts ac at about 180 rpm.

I can turn the shaft with one hand. It does turn a little lumpy, but considering the magnetic field on the shaft (12 lbs pull each X 48 magnets) I am thrilled with how easily it can be turned.

It will soon get a steel hub & a 6' 3 blade rotor.

ghurd · « **Reply #1 on:** February 02, 2007, 07:49:19 AM »

Beautiful rotor!

What is your battery bank voltage?

G-

Slingshot · « **Reply #2 on:** February 02, 2007, 08:11:10 AM »

I'm glad to see someone else is using those "Harbor Freight" multimeters. Some of my friends discount them, but I bought 6 at $2.99 apiece on sale a few years ago. I connected them all to the same variable power supply, and all were within about 10 millivolts of one another over any range I cared about. And, so far, I haven't had to replace the batteries in any of them!

asheets · « **Reply #3 on:** February 02, 2007, 09:50:16 AM »

Every time they go on sale for $2.99 at the local HF, I grab about a dozen. They make great gifts for friends, I've donated a bunch to the local technical college I teach at, and I use a bunch around the house. My 4 year old also gets to play with one (which is also pretty nice, because all I had at 4 was my dad's old Heathkit analog meter that the needle got bent on).

DanB · « **Reply #4 on:** February 02, 2007, 09:51:20 AM »

yes, those cheap meters are a bargain but I wouldn't trust one - especially if your monitoring battery bank voltage where a fraction of a volt is important. The ones I have give a reading that's 'in the ball park' but they range quite a bit depending on the condition of the battery that powers them. I have one with a back light - and if you turn on the back light the voltage reading drops significantly.

Good for some stuff - but not terribly accurate.

Slingshot · « **Reply #5 on:** February 02, 2007, 11:40:59 AM »

I haven't tried the ones with the backlights, but the standard ones that usually go on sale for $2.99 have proven to be pretty accurate.

Nando · « **Reply #6 on:** February 02, 2007, 12:37:27 PM »

Dan:

I tested them with calibrated equipment and the accuracy is better than 0.3 % this is due to the resistor networks.

the accuracy is GOOD enough for the general work that this group does.

I have designed a small circuit to have an isolated 9 volts supply to take the batteries away and been able to use the with the supply voltage I am working with them.

Nando

Spdlmt150 · « **Reply #7 on:** February 02, 2007, 03:01:16 PM »

Good question, although it should be "what will the voltage be?"

As of now, I'm running 12v. One pair of 220AH 6v batteries. Seeing that this gen looks like it could go 12 or 24, I'm toying with the idea of using tax money to switch to 24v. I still need to get rectifiers for it & see what the actual rectified output will be. It seems that nobody locally sees the need for rectifiers over 20A. After I can get actual DC readings on it, as well as figure out what my tax return will be, I'll make a decision on it. I was planning to get a decent sine wave inverter when the money comes in.

The Inverter Store has a 3000W digital sine wave inverter for the same $949 at either voltage. My charge controllers can run either. My PV panels can be reconfigured for 24v. The only thing I would have to drop would be my inverters. I have an 1800 watt, and a 375 watt. Both are Tripp-Lite. Both have served flawlessly for several years now.

I suppose the voltage question won't be answered for a little while. As soon as I make the decision, I'll make it known.

harrie · « **Reply #8 on:** February 02, 2007, 09:07:38 PM »

Hi, Wow, very nice work, its hard to beleive you can keep everything so clean while your working. It looks like it was worth doing too, keep us informed and thanks for sharing.

Spdlmt150 · « **Reply #9 on:** February 03, 2007, 10:25:54 PM »

Now that the baldour is fitted with rectifiers, here's some real numbers. It is wired star. Two windings check 2.4 Ohm, one checks 3.5 Ohm. Driving it with an electric drill rated at 1200 rpm, it puts out 109.4 volts. This should put cutin (based on voltage) at:

14.0v - 153rpm

13.5v - 148rpm

13.0v - 142rpm

12.5v - 137rpm

12.0v - 131rpm

11.5v - 126rpm

11.0v - 120rpm

10.5v - 115rpm

I don't yet have it fitted with any way to drive it under a load. As soon as I do it will get hooked up to the 12v batteries and I'll post amperage numbers.

SparWeb · « **Reply #10 on:** February 03, 2007, 10:55:17 PM »

Welcome to the world of motor conversions!

Nice work. I look forward to seeing test results, too.

Spdlmt150 · « **Reply #11 on:** February 07, 2007, 08:04:43 PM »

Now for some semi-real numbers. Driving the gen with a cordless DeWalt drill rated for 400 rpm in low range, dumping into a car battery.... I know without a doubt the drill wasn't pushing 400 rpm, roughly somewhere between 200-300, the gen dumps around 3 amps into the battery. It brought the voltage up at a scary rate. The battery started out showing 11.9v, and after about a minute it was pushing 14v.

Next will be coming a steel hub to get a rotor mounted.

Spdlmt150 · « **Reply #12 on:** February 09, 2007, 04:08:42 PM »

My initial thought for a hub for this gen was to cut a keyway. With the shaft size, I don't think I want to weaken it in any way. I figured a split sleeve with locking screws should be able to hold up if made strong enough. The shaft has a 3/8-24 thread in the end. The sleeve will have three 1/4-20 screws down each side, and all will get loc-tite to make sure they don't back off.

Next will be an 8 inch x 1/2 inch disc with a 1/4-20 bolt pattern for mounting the blades. It will be welded to the end of the sleeve. I am hoping that this will be as permanent as a hub can be. After the hub is finished, it will get a desperately needed paint job.

Spdlmt150 · « **Reply #13 on:** February 09, 2007, 06:36:39 PM »

Rectifier mounting. I ended up using loc-tite superglue on the rectifiers. I figured drilling for a screw would end up letting more moisture in. Everything is crimp-connected. It's definitely a tight fit, but everything is in & should dissipate heat fairly well.

Spdlmt150 · « **Reply #14 on:** February 14, 2007, 08:35:28 AM »

The rotor ended up being stainless. It was the only thing I had on hand. I'll even post my horrid welding job.

As it is outside, I don't think I'll be putting up a tower anytime soon. For the sake of seeing it turn, it is outside for a trial. Not optimal conditions, but it's reached 3 amps charging so far.

Now it's a long wait for decent weather to get it up on a tower.

ghurd · « **Reply #15 on:** February 14, 2007, 12:07:44 PM »

That took guts, just going outside. Had to shovel out the car twice so far today.

Trust me, the table and not being able to track the wind has a very serious impact on the output. It'll do a lot better even 6' up.

G-

Spdlmt150 · « **Reply #16 on:** February 14, 2007, 07:07:27 PM »

I know it's about the worst possible conditions for it. Doing this gets it out of the house, and actually turning more often than not. I've had a couple gusts push it up around 3 amps output, but it certainly isn't going to be doing much at ground level locked down in one position. It's more a case of me getting the satisfaction of seeing it spin, getting some of the clutter out of the house, and a quick & dirty test of startup ability. Considering the conditions outside, I don't think I'll be doing anything more with it until things thaw some. After seeing it spin up fairly easily, I can't wait to get it up in the air.

Spdlmt150 · « **Reply #17 on:** February 25, 2007, 04:23:56 PM »

As the weather is horrendous, I decided this would be a good time to do some indoor work. The 5 ft (cut an angle & slap it together) rotor has obvious startup issues. Once it gets going, it spins good although the tsr is way off. I decided to make a "real" rotor for it. What I ended up with is a split-the-difference culmination of numbers from Hugh's spreadsheet, and the Warlock blade calc. I don't like the idea of laminating anything, so I stayed with single thickness boards.

After all is said & done, these will make a very light weight 6 foot rotor with a tsr around 6-7. Two down, one to go. Lots of cutting with a hammer, chisel, and draw plane.

I also have started on the yaw assembly to go over a 2.5" pipe. Providing I can get a break in the weather I am hoping to put it on a 10 foot test pole very soon.

Spdlmt150 · « **Reply #18 on:** April 06, 2007, 04:24:53 PM »

Update! After a considerable amount of time thinking that this conversion was a complete failure, I have good news. First - the problem. I watched this thing run around 300 rpm stalled hard. Regardless of the wind speed, it would hover around 300 & not run much faster. Absolute maximum of .5A charging.

Not acceptable.

I brought it back inside & started checking things out. Tested the windings for a short, and all looked good. The run windings in this motor checked 2.4Ohm, and the start winding checked 3.6Ohm. I figured dropping the start might allow things to loosen up. I rectified the two run windings, & taped off the leads from the start. Re-assembled everything, and back outside it went.

I like having a meter outside directly from the gen so I can watch the electrical & mechanical at the same time. I wired things in to the batteries, turned on the meter, and let things loose. Wind was around 15mph at that time. After seeing the 6ft rotor turn so slowly, I was shocked when it spun up to a blur almost instantly. 3-5A charging, and a rotor speed that is a little unnerving. I stood outside in the freezing wind for 2 hours to watch for signs of any problems. Nothing but a swishing sound & a good steady charging current. All is well.

Seeing the output as it is now - bolted to a picnic table with the tip of the rotor 2 inches from the ground, faced stationary into the prevailing wind, lots of obstacles to block the flow of wind.... I expect that once it ends up on a pole, I should see some impressive output from it. I have no idea why rectifying the start winding causes it to stall so badly, but I can live with the output I'm getting without it.

ghurd · « **Reply #19 on:** April 09, 2007, 08:54:05 AM »

They may be shorted. It sometimes doesn't show up with a meter.

I had that problem a couple times. One didn't act shorted until the volts got higher. One didn't act seem shorted, but wouldn't make many volts compared to the other coils.

G-

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Author Topic: Baldour motor conversion (Read 9345 times)