Homebuilt handmade "3 phase" electric motor

[skimask]

Yep, that is why synchronous motors do not have good starting torque.

Then how do they get those AC types to work in electric cars (the ones with AC motors anyways) and the like?

I do not bring the 2 phase thing up often. You should see the look on an inpectors face when I label a sub panel "2 PHASE".

I checked the wiring at my house awhile back on a 'scope. I've got 2 legs of 120VAC, both in sync with each other, not 180 or 60 or 120 out of phase. What's up with that?

Might be able to use welding rod. Laminates are used in transformers to suppress eddy currents, in small motors for cost. Large motors are cast iron/steel with a second pour for the aluminun. Air gap should be the same for magnetic and non magnetic parts. Sounds like you have punch press, How about a lathe? To attach things for testing, J B Weld.

No lathe, no punch press, just access to a foot shear and a decent ruler, should be able to punch out a pile of decent rectangles in short amount of time. I wasn't going to use JBWeld, just whatever epoxy I could find that would work reasonably well on sheet metal. If that doesn't work, I'll pop-rivet the parts together. If I had a plasma cutter, I'd cut out chunks of frame rail and use that instead of the stacked up rectangles.
I don't have any welding rod handy, and I've got all this old scrap auto sheet metal laying around.

Can you imagine the spinning in Tesla's head. He reportedly modeled this all in his head.

I have trouble enough with 2 dimensions, let alone more than 3...by that I mean trying to imagine the interaction between voltage, current, and magnetic lines of flux...all at the same time...

Do ya think it matters much that I'm driving the thing using square waves vs. a halfway decent sine wave?

[mackrackit]

The AC electric cars I have looked at use Async motors like the one you are building. Spped control is easy with a varibl frequency drive like the one you are building. Depends on how the motor is built as to the low rpm torque developed.

Synchronous motors with rotor windings to a controler can give good low rpm torque but then the overhead will increase, and more trouble with slip rings and all of that.

I knew I was going to confuse something. Your house like most I think have one transformer connected to one of the phases provided by the power company. The transformer has two output taps, both 120 volt. So both legs are on the same phase.

A typical 240 three phase will have one 240 leg and two 120 legs. ( some are 208/277 but that is another story) All coming from different transformers. Look at a power utility pole. If I place a meter across any to legs or phases it will read 240 volt. The water heater thing I mentioned is what messed this up .

The attached pict is a schematic of a water chiller. The compressor is 3 phase and the circulation pump is a standard 240 volt setup. The pump motor runs from two of the 3 phases making it a two phase motor. The same motor will also run on the 240 two leg single phase at your house.

But you can not feed a transformer with one phase and have three taps and run a 3 phase motor.

[mackrackit]

Hi Skimask,

Did you get your motor working?

[skimask]

Hi Skimask,
Did you get your motor working?

Not yet, kinda slowed progress on the motor, holidays and stuff (birthdays, parties, etc).
I've gotten it to kick quite a bit, but not go 'round and 'round...so that's probably a software issue.

[mackrackit]

Understaand all of that (family first).

Might be a time problem. Could you post your algorithm. Might be able to help.

[skimask]

Might be a time problem. Could you post your algorithm. Might be able to help.

Don't have it here at work, but it's not as complicated as a person might think.
Just watch for the phototransistor input and switch to the next 'phase'.
I'm able to move the reflective strips to, in effect, change the timing of the 'phases' in relation to the coils.
The leds I have mounted to the base of the motor tell me everything is working as I've planned it to work.
It's got to be a problem with the air gap, or maybe I've got one of the coils wrapped backwards/sideways/upside-down, something simple.
It should work without a problem. I'll get 'er nailed down someday.