Why 90VDC and 180VDC motors?

Discussion in 'General Electronics Chat' started by KMoffett, Aug 20, 2013.

  1. KMoffett

    Thread Starter AAC Fanatic!

    Dec 19, 2007
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    I know that 90VDC motors are used with 120VAC controllers and 180VDC motors are used with 220VAC controllers. But why? Peak rectified 120VAC is almost 180VDC.

    Ken
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That is with PWM drives, the 90v and 180v are designed mainly for SCR bridge phase angle controllers, although there is no harm running them off of PWM if the Maximum mean voltage out is restricted to their maximum RPM.
    Max.
     
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Yeah most <5hp drives are SCR drives, and they don't actually rectify like you would think, if you're coming from a battery power background; that is, they don't wave rectify into a cap bank and then PWM. They're more like an AC power controller than an a DC drive that you might find on an RC toy or ebike or EV. So the peak rectified voltage isn't of much consequence. A lot of the drives can be run from 240VAC @ xHP or 120V @ .5xHP.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    SCR ,particularly 3ph drives have been around from the advent of DC servo's.
    Also for spindles in motion control applications, 5 Hp and up are usually 3 phase SCR Bridge.
    Usually now a common source of these 90v/180v motors are from Treadmills.
    And Baldor or KB are a popular supplier of the drives, both SCR and PWM.
    Max.
     
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