dc brake for ac three phase motors

Discussion in 'The Projects Forum' started by niceguynorthwales, Jul 24, 2012.

  1. niceguynorthwales

    niceguynorthwales Thread Starter New Member

    Joined:
    Jul 23, 2012
    Messages:
    1
    hello to all, new to this site.
    i was hoping someone here could help, we have a machine with a three phase 415v 3 kw motor, the starter for the motor was fitted with some form of :homemade: dc brake, however the starter was practically demolished during a move.
    i know there are ways of making your own dc brake, does anyone know the circuit and components required, we would be deeply grateful for any assistance.
    thankyou
  2. strantor

    strantor Well-Known Member

    Joined:
    Oct 3, 2010
    Messages:
    3,805
    Location:
    Houston tx
    When you say DC brake, are you referring to an actual physical brake attached to the motor, like an eddy current brake, or are you referring to some sort of DC injection scheme?
  3. BillB3857

    BillB3857 Senior Member

    Joined:
    Feb 28, 2009
    Messages:
    2,195
    Location:
    St.Louis, MO area (GMT-6)_
    We had a machine with 50/100 hp, 3600/7200 RPM, 60/120Hz direct drive spindles that used a low voltage high current transformer feeding a bridge rectifier. When the spindle was commanded to stop, a timer circuit 1) insured drop out of main A/C contactor, 2)supply low voltage DC to two leads of the motor for a fixed time 3) drop out and release DC to motor. It was also interlocked to prevent attempts of starting the spindle during the braking cycle.
  4. GetDeviceInfo

    GetDeviceInfo Senior Member

    Joined:
    Jun 7, 2009
    Messages:
    1,510
    Location:
    Canada
    another application I've worked with saw arbors where a rectifier is connected across the lines in the motor terminal box. The DC pulls off a spring loaded brake when powered. On loss of power the brake brings the arbor to an accelerated stop condition.
Similar Threads
Forum Title Date
The Projects Forum Three-Phase Current Chopping, Eddy Current Brake Jan 8, 2009
The Projects Forum rc car brake lights . Friday at 11:47 AM
The Projects Forum Brake light flasher circuit Feb 18, 2015
The Projects Forum Increasing frequency pulse generator (for motorcycle brake light) Jan 5, 2015
The Projects Forum Wireless solenoid bicycle brake project Oct 27, 2014

Share This Page