Author Topic: Need motor/alternator gurus  (Read 813 times)

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Harold in CR

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Need motor/alternator gurus
« on: August 05, 2017, 02:57:53 PM »

 If I need photos, I might be able to get them online, maybe.

 What I have is, a GM 3 phase alternator/starter e-assist for added power for smaller engines.

 There is no affordable to me off the shelf controller. A Curtis would be about $1100.00. I'm messaging several people about modding controllers.

 Anyway, I have recently made a 3 phase 1.5 HP induction motor into a Perm Magnet generator for wind turbine, using the Zubbly technique. Took a lot of figuring and slight error fixing, but, seems ready to mount up for my wind turbine at around 500 RPM or so. 

 Question is, what is y'alls advice about redoing the rotor OR making a new one, to change the induction alternator into a Perm magnet motor. There are plenty of PMAC vehicle controllers on the market. This will hopefully power my 3 wheel motorcycle.

 This motor has 75 stator poles and 56 rotor poles. I'm guessing the rotor to be 3-3.5" dia. X 4" long. This motor should turn up to 4500 RPM's and Zubblys cage design could be wrapped to help hold the cylindrical magnets along with the hi temp epoxy or resin. This also has a resolver that needs a circuit board to convert to an encoder for syncing the controller and motor so it works properly.

This thing is water cooled, so, heat should be held reasonably stable. At 80V and 550A out of the controller, it should give 40HP.

 I know without pics this is all a guessing game, but, might it be possible and practical??  I'm game to try it since I did a fair job on the smaller induction motor. These things are cheap compared to an equivalent Perm Magnet Motor of this caliber.

  Yeah, I'm also crazy.  ::) ::)

joestue

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Re: Need motor/alternator gurus
« Reply #1 on: August 05, 2017, 08:07:57 PM »
this might be your most practical solution
https://pandspowerelectronics.ecwid.com/#!/P&S-Power-Electronics-3-Phase-POPULATED-AND-TESTED-AC-Control-Driver-Board/p/59121602/category=16287307

i believe that board was the evolution from earlier designs described here
http://ecomodder.com/forum/showthread.php/paul-sabrinas-cheap-3-phase-inverter-ac-controller-10839.html


You'll need 6 igbts or 3 half bridges. also you'll need appropriate capacitors for the inverter (its as important to get that right, as it is to drive the igbts properly), which could be pulled from junked hybrid car inverters/battery modules (some of them have a voltage doubler located in the battery compartment that doubles the battery volts, typically from 200-300 to 500 volt range).


are you sure you have a 75 slot stator? 72 would be more normal. is it wound for 8 poles?

anyhow if you want to get reasonable power density from that motor, then surface mounted neodymium magnets would be ok, if you can figure out how to retain them at the rpms you want.. perhaps most hybrid cars are now making switched reluctance hybrid motors that have buried magnets and they get about 30% more torque from the motor by doing so.

Harold in CR

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Re: Need motor/alternator gurus
« Reply #2 on: August 05, 2017, 08:30:49 PM »
 I'm in contact with Paul Holmes about that populated board. I also have a salvage Honda IMA controller for the lower voltage (150) max. I believe they use Mosfets instead of IGBT's. There is only so much battery space in a motorcycle frame, but, I have modded this one for a 30S Chevy Volt pack and, can add a few Leaf modules on top of the Volt pack to boost voltage to 144+.

 I have 2 contacts for the resolver to encoder board, also. There are things I don't understand, electronically, but, I have others standing by to assist, if need be.

 That was a typo at 75, should have been 72.  :-[  Not sure about the 8 pole windings. This is, as far as research goes, a switched reluctance motor/alternator, which makes it that much more difficult to find a reasonably priced controller.

 I have done a lot of searching, and, seems that nearly all OEM motors are Permanent magnet and internally mounted as a transmission type motor/charger.  The 1st Gen of these had the buried magnets and they were not very powerful. These 2nd gen have the hairpin type stator windings.

 I'm trying to find my best option, and, you may have just cast the deciding vote.

 Thank You, Joestue
« Last Edit: August 05, 2017, 08:35:17 PM by Harold in CR »

joestue

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Re: Need motor/alternator gurus
« Reply #3 on: August 05, 2017, 09:10:38 PM »
if the motor has magnets, then its a permanent magnet motor and can be driven by any driver.

its when they bury the magnets that you get a torque boost from the coils in the rotor "pulling" on the iron that is around the magnets--and in order to take advantage of that you need an encoder so that you know how close you can get to the limit.

https://www.youtube.com/watch?v=uLNINuNwOhQ skip forward to 14 minutes..

Harold in CR

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Re: Need motor/alternator gurus
« Reply #4 on: August 05, 2017, 11:05:54 PM »

 I need to go back and watch that video again. 1 Part describes that surface mounted magnets show very little voltage drop under load, whereas embedded magnets show a large drop in voltage under load.

 Would this be a bad feature in hilly areas ?  I thought voltage equals speed and amperage equals torque ?  This is over my head somewhat. There are a couple threads talking about the older model e-assist type altermotors, and, they just didn't have the oomph to get the job done.

 If surface mount magnets could be a much better option, the older models might just do for motorcycle conversions.

 Down here in CR, I have people talking about conversions, but, that has to be an affordable option with really good mileage capabilities.

joestue

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Re: Need motor/alternator gurus
« Reply #5 on: August 06, 2017, 02:27:44 PM »
In order to take advantage of the embedded magnets when using the motor as a generator, you need a rectifier that draws leading power factor.

Harold in CR

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Re: Need motor/alternator gurus
« Reply #6 on: August 06, 2017, 05:28:34 PM »

 Thanks. More studying to do.  8)