Speed controller for ac motor

Discussion in 'General Electronics Chat' started by tobertuzzi, Aug 25, 2014.

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  1. tobertuzzi

    Thread Starter New Member

    Aug 25, 2014
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    Hi everyone
    I am trying to figure out the best way to control the speed of this motor.
    Its from a treadmill specs are

    HP 5
    rpm 1745
    volts 230
    HZ 60
    3 phase

    Im trying to make a chicken plucker with it so I need to slow it down.

    https://www.youtube.com/watch?v=G-pbRxIlpuw

    Thanks in advance

    Toby
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You need a VFD, they will take 240v 1ph domestic supply and convert to 3 phase variable speed.
    Hitachi are a good make to look at.
    Ensure it is not a permanent magnet motor first. Short the three leads together and try and give it a fast spin, if it resists then it is a P.M. motor and will need a BLDC or other type of control.
    Max.
     
  3. b1u3sf4n09

    Member

    May 23, 2014
    115
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    If you are looking for a homebrew solution, I've attached a Microchip application note that is actually a relatively affordable solution.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That is aimed at an induction motor, if the OP's has a P.M. rotor it most likely will will not be suitable.
    Max.
     
  5. Lestraveled

    Well-Known Member

    May 19, 2014
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    Max
    The legend on the side of the motor says it is a 60 HZ, 230V, 3 phase motor. What makes you think it is a permanent magnet motor??
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Because it looks like one, it's from a treadmill which usually are PM motors, and it says on the label not to run from mains AC but only from the special controller. :)

    An obvious solution would be to try to find the original controller or buy a compatibale 3ph treadmill motor controller from ebay etc.
     
  7. IamJatinah

    Member

    Oct 22, 2014
    70
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    Hi All, I think I know the mating motor controller that drives this in a treadmill, and you can then simply drive the control board with a ttl-level drive control PWM and slow things to a crawl ;o) Message me for details, but if you have the original controller, verify it was made by Design Concepts of Missouri, Inc, and there will be a sticker on the frame of the controller which says ASM-xxxxx-xx. If you do not have the controller I may have one ;o)
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Do you have a original board Schematic for the motor?
    Max.
     
  9. IamJatinah

    Member

    Oct 22, 2014
    70
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    Hi Max, well, I don't have an original schematic, but this unit has also undergone reverse engineering and is about 90% complete, as we stopped at the micro after finding relevant pins and I/O's. This controller board that mates to the StarTrac motor should be part number from DCI(the manufacturer of the controller) ASM-ACD1U-xx and will have a StarTrac part number of 715-xxxx. This is a variable freq and amplitude 3-phase drive scheme, using 6 IGBT drivers in a "high/low" side AC inverter system. Speed control is accomplished thru a change in frequency usually in these ac drives, leaving the amplitude intact and simply varying the frequency to the windings. The schematics I draw are done on the ExpressSCH software which is freeware available on the web, if you'd like what I have drawn out of a very similar unit by this manufacturer, or I can try to convert it to .pdf but it is 6-pgs long and has quite a part count on the double-sided smt heavy pcb. :eek:)
     
  10. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I would just buy a good used VFD and be done with it. You won't build one for less than you can buy a good used one.

    I occasionally need VFD's in the 5 Hp range and get them off eBay for around $50 - $75.
    Also given it's a treadmill duty and special service factor plus only draws ~6 amps per phase most 3 Hp VFD's would have no problem driving it. Especially so if all you need it for is low RPM light load work.
     
    Last edited: May 23, 2015
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I suspect from the plate it is a P.M. motor, (BLDC) as the plate also states, 'Do not Connect directly to AC line.
    Also on a T.M. you would need var speed, this is why I wondered if the original board was there?
    I tried a P.M. BLDC motor on VFD with poor results, according to Hitachi, theirs have to be specially conditioned.
    There is also many BLDC servo drives out there that will do it by simply adding a 5k pot.
    In 8mths the OP may have already found an option?
    Max.
     
    Last edited: May 23, 2015
  12. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    Hi, Do you have motor controller made by Design Concepts of Missouri, Inc. ASM-ACD1U-4C 715-3617?

    The member zeljkostoj asking a question --> Motor controller made by Design Concepts of Missouri? ... Scott Wang.
     
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