DC Motor Help

Discussion in 'General Electronics Chat' started by sbaysting, May 19, 2013.

  1. sbaysting

    Thread Starter New Member

    May 19, 2013
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    I'm trying to get a motor running, the board it's connected to has a 120VAC input and approx. 80VDC output, I've metered the input and output and they're fine, but once I hook up the motor to the 80VDC output, the voltage drops to nothing. Any ideas on how to proceed? Thanks

    Sam
     
  2. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    Sounds like the power board doesn't have enough current capacity for the motor. What is the volts/amps requirement for the motor? What is the output current of the board?
     
  3. sbaysting

    Thread Starter New Member

    May 19, 2013
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    I'm pretty sure the motor should be running on around 80VDC and about 1A. I'm assuming the board is supposed to put out that much too because it should be running the motor but I'm not entirely sure. I'm sorry, I'm not working with a whole lot of information here
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    Is the board a commercial offering, and if so provide a link. What's the motor's hp rating, and what is the board rating.
     
  5. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
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    Most motor's draw many times their running current at start up, so you could have an issue with current limiting if the board can only supply 1 amp maximum.

    You could connect a test load to the board to check its operation.
    I think a 120 volt 100 watt lamp as a load might be Ok. If that works, then add another lamp, see if it drives that.
     
  6. sbaysting

    Thread Starter New Member

    May 19, 2013
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    I can't find any information on the board. It's a board that runs a motor for a GMC 16 inch scroll saw. It's 120VAC in, 80VDC out, or so it seems. There not a whole lot of information on the motor either. But if it can't hold it's load on it's not drawing enough current, what could be wrong with the board? Rectifier? Transformer? I checked all of the resistors, diodes, transistors and such and they're fine, so it's more than likely one of those two components. At least, that's what I've narrowed it down to, unless it's the motor itself. Then again, I'm not as experienced as some of you, which is why I'm here. Thanks guys, any more ideas will be great.
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
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    can you post some pictures of it then ?
     
  8. sbaysting

    Thread Starter New Member

    May 19, 2013
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    Here is one picture of the board, and two pictures of the motor. I'm not sure if the pictures of the motor will help much. However, I did find a number on the motor, but only the prefix, so when I google the number a datahseet comes up with a whole bunch of different voltages and amperages so I'm not sure. The number is ZYT76

    https://www.dropbox.com/s/cnj8q0yn5bzv55u/2013-05-27 22.07.25.jpg
    https://www.dropbox.com/s/5guwjbh0sqzzaub/2013-05-27 22.08.25.jpg
    https://www.dropbox.com/s/dvo558q9c7ltxkn/2013-05-27 22.08.33.jpg
     
  9. bug13

    Well-Known Member

    Feb 13, 2012
    1,208
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  10. sbaysting

    Thread Starter New Member

    May 19, 2013
    5
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    Yeah its not very big at all. 3.25 x 2.5 inches
     
  11. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
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    Could you post part numbers of the square bridge rectifier, the transistor? at the center of the flash, and the part on the heat sink?

    What's the resistance across the motor?
    You might try testing the motor on a 12 volt battery to see if it runs. If the motors ok it should likely still run slowly on 12 vdc.
     
    Last edited: May 29, 2013
  12. Gary_P

    New Member

    Apr 4, 2013
    7
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    Does the motor run if you connect it to a stout 12V supply?

    It should start and run slowly. I've tested treadmill motors this way.

    Oops, didn't see the above post...
     
    Last edited: May 29, 2013
  13. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    Must be a REALLY good idea. :D
     
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