Will this motor convert decently?

[JMaris]

Hey guys,
I met this old guy who runs a small back yard buiness. He repairs commercial appliances. I asked him if he had any used 3 phase induction motors laying around he wanted to get rid of. He grins and says I will be right back. Runs in his shop and comes out with this...   
 

It's a brand new 1hp 3500rpm 230v 3.4a or 460v 1.7a doerr motor. Guy says he has had it for years as they no longer make the washer that goes in. Sold it to me for pretty cheap. I know it's high rpm's but do you guys think it will make a good wind gen?

[SparWeb]

...brand new 1hp 3500rpm 230v 3.4a or 460v 1.7a ...

It's a bit of an off-hand guess, but the end result (magnets on rotor, wires connected Jerry) may give you about 5-10 Amps, after being rectified, but may only do well in a 24v system or higher.  Since the motor is free I'd say it is a great target for a first shot at a conversion to "learn the ropes".

... they no longer make the washer that goes in....

Red flag.  If it's just a little spring-washer or a spacer to apply correct pressure on the bearings, then the washer it lacks is very easy to come by or make.  I fear that since the guy at the shop didn't do this already, that he is talking about something totally different.  Not knowing anything about your motor, I'm speculating that it doesn't actually have ball bearings and has journal bearings instead.  Not really the end of the world, but in a wind turbine this wastes a lot of energy with friction on the shaft.  Other things to check when picking up stuff people don't want:  shaft could be bent, bearing could be seized (kinda obvious), an end shell cracked, motor was dropped...   The reasons that motor isn't being used are endless.  So before you decide what you'll get out of the thing when you are done, take the whole thing apart, clean it up a bit, and decide if there is anything fatally wrong.

[wpowokal]

Short answer no, could it yes, should you bother no. With suitable magnets it would make a small generator for 12 volts DC but you would need access to machining to be worth the effort, I like conversions for their solid construction, depends on many factors as to whether you should bother with this one. Tell us what you are aiming for ie system voltage expected output or is it just a project to get into the field.

Had the "old guy" sold you a permanent magnet motor you would have had a good first project.

Now I have made a post you will get some replies.

allan

[wpowokal]

Spar I think he meant that brand of washing machine is no longer made.

allan

[Isaiah]

 You want to look for a pm or permanent  magnet motor or a ecm motor. some permanent magnet motors the field is the magnet like two or 4 big horse shoes. the armature has the windings and their is not much the average guy can do to change the wireing in these they will work but what you get is pretty much it.
The ecm's have the magnets on the armature and the fiedls are your windings and  you have a lot of options to rewire it to get the most out of it.
   In looking you want to find a motor with low rpm's hi voltage and the higher the amp rating the better.
Take your rpm's divide it by your volts  then multiply that answer by 15 and that answer will give you the rpm's the motor will have to turn to make useful 12 volt out put.
 1710 rpm's divided by 90 volts =19 x 15 =285 rpm to produce useful voltage.another thing to concider is your average wind speed.
 If you have a very low average wind speed  the lower the motor rpm's the better but the overall output will also be low depending what you want to do ?
 you may want to tie it in with solar panels.
 There is a lot of fun and enjoyment in building these things and seeing them work.

[JMaris]

So should I devide 3500(the rpm) by 230 or 460 because it lists both of them as the voltage

[wpowokal]

Your motor as is will not generate power on its own, if it was a PM motor you would divide RPM by volts to arrive at RPM/volt but yours is not one of these, watch this space as someone will jump in with over driving an induction motor with capacitors on the output.

allan

[SparWeb]

... jump in with over driving an induction motor with capacitors on the output.

Yeah, and we don't see a lot of those on this site.  Tricky to do.  Running an engine (to drive that motor) that fast also makes a lot of noise.  Quickly gets us off topic. 

Back to asking about wind:  You need a generator that works at a low speed to be useful for wind.  Some manage to step the speed up with pulleys and belts, but my preference is direct-drive.  The solution is to modify the rotor, machine it to size so that permanent magnets fit, then stuff it back in and hope for the best.  If you don't have any particular purpose in mind for the finished wind turbine, then I wouldn't go judging if it's worth doing for 200 watts but not for 100 watts or something - that's a case where the fun of doing it justifies the means.  On the other hand, once the turbine is there, like in my case, the uses become clear in the mind, and suddenly you want to use more energy than it can supply!

...And about what I wrote before...

...yeah, that kind of washer.  Duh 

[wpowokal]

I for one have to refer to Zubbly's info but I do like conversions.

allan

[JMaris]

Well I plan on converting it either way... I have never done one before and figured it would be a good motor to get my feet wet with. Which, now I have this motor, a big industrial use delco alternator, and a 3hp 3 phase motor. Eventually all 3 will be converted, I just have to pick one to start with and figured this one would be easier/easiest to start with.  I still have to learn about all the system setup and stuff first also, but I guess alot of that will depend on what my genei will do.

[ghurd]

Go for it.
I think you will get some good experience with something like that.
How fastening the magnets, to the limits of the power curve, can cause troubles.
Better to learn on something that is not expensive!

I think I would expect the higher end of SparWeb's limits. 9~10A?
G-

[JMaris]

So how do I tell how many poles the motor has? It doesn't tell on the info plate.

[adaml]

I would say go for it, you have it for cheap, is a great way to get your hands dirty and begin figuring out how everything has to "fit" together.  Have a go or you'll never know!  It doesn't have to look pretty especially as a first learning experiment, often getting things wrong helps learn how to get it better (or right?!) next time round.  Get the rotor cut down and slap in some mags...................................
Other, wiser members I'm sure can be more technical and specific but that is my philosophy!

[wpowokal]

3500 rpm@ 60 hz says 2 pole motor

allan

[wpowokal]

I could have been clearer on that post, basically motor speed divided by frequency, not forgetting to bring frequency to the same units gives number of pole pairs (one north and one south)

So in your case 3500 RPM divided by cycles/ min (60 x 60) , ops does not quite work, it does actually, as all motors have slip (a separate subject) that is necessary to develop the torque to do work, so your motor is rated for 100 RPM slip. Your motors synchronous speed (think of this as unloaded speed almost) is 3600 for 60HZ so it has one pole pair 3600/3600 = 1

Allan (expert at clouding the issue)

[opo]

Yes, go for it! I think it is a good find.

Somebody said once: Do not expect a lot out of it and you will not be dissapointed.

Cheers.

Octavio