DC motor speed control

Discussion in 'General Electronics Chat' started by JMS6449, Feb 27, 2009.

  1. JMS6449

    Thread Starter New Member

    Nov 20, 2008
    4
    0
    Need some dc motor control help

    motor 5hp 200vdc 1150/4000rpm shunt wound

    controller browning mws 300/500 controls armature volts only
    field adjustment is not an option of this controller

    field resistance 284ohms .74a @200vdc

    what size rheostat to increase rpm

    i have a 200ohm 150 watt on the field and top out at 1680rpm (this was the size recommended by motor tech)

    the more i read about this the further crossed my eye become.

    any help will be greatly appreciated

    thanks

    Help!
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    What do you want to control? armature voltage or field current?
     
  3. JMS6449

    Thread Starter New Member

    Nov 20, 2008
    4
    0
    the briwning already controls the armature voltage, need to reduce
    field voltage to up rpm
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Note that if you reduce the field current the output speed will increase but the torque will decrease.

    What is your current solution to this?
     
  5. JMS6449

    Thread Starter New Member

    Nov 20, 2008
    4
    0
    no problem with reduced torque. this is high speed
    on a metal lathe. used primarily for polishing.
     
  6. b.shahvir

    Active Member

    Jan 6, 2009
    444
    0
    I would agree with mik3......... it's much better to go with field control, even though torque is sacrificed, at least the size of speed controller and heat dissipation by the controller will be much less! Gud Luck
     
  7. JMS6449

    Thread Starter New Member

    Nov 20, 2008
    4
    0
    IT LOOKS LIKE THERE IS NO ONE THAT CAN ANSWER THE RHEOSTAT SIZE ??? WHERE ARE THE MOTOR GUYS
     
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