Thread: speed controler

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  1. #1
    hi guys i have a KBelectronics speed controler KBLC-240D
    not sure what horsepower resister to use with my motor


    kbelectronics told me to use .18 ohm but i dont think thats correct as the resistor exploded
    as soon as i turn on the power LOL qwickest 10 i have spent in a while



    motor specs sherline mill motor

    Duty rating: Continuous--10 oz. in. at 6100 rpm, .85 amperes; Intermittent--30 oz. in. at 5500 rpm, 1.75 amperes (5 minutes on / 15 minutes off)

    Output horsepower: .06 KW (60 W) at 10 oz. in. / 6100 rpm

    DC voltage:90 VDC to motor (60 Hz)
    Speed in rpm: 6100 rpm continuous
    Class of insulation: Class A, 105 (C.) insulation system
    Normal full load current: .85 amperes Starting current: 17 amperes instantaneous starting current (<100 milliamperes). This is also stall current in True RMS

    anyone got any ideas???

  2. #2
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 19 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,831. Received thanks 192 times, giving thanks to others 5 times.
    Are you sure everything is wired correctly?
    I wouldn't expect the resistor to fail like that, as all it does is control how much current goes to the motor. All I'd think the wrong resistor would do, would be either not let enough current reach the motor, or too much current.
    I'd try contacting KB and see what they suggest.

    What voltage are you powering the KBLC with?
    For a 90V motor, it needs to be powered with 115Vac...

    Also, on a side note, where did you get your KB drive?
    (I'm currently looking for a DC motor controller, without the expense of shipping one from across the pond)

  3. #3
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 19 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,831. Received thanks 192 times, giving thanks to others 5 times.
    Just to clarify, what drive do you have?
    Although the KBLC-240D can be found via the search on the site, it points to the KBIC manual/datasheet...

  4. #4
    the controler is in my milling machine but axiscontrols sell them here in the uk KB recon it would control my 90v motor
    not sure what its getting powered buy but if you turn the max speed pot down to min you get 0-90vdc turn it to max you get 0-200vdc
    not sure on the other two pots torque and cant remember what the othes called i know its some sort of compensator
    i think torque is amps not sure on that though cant test what amps I`m getting

    speedcontrolers hate me lol my sherline mill speedcontroler died now possably this one in my other mill all KB Controlers

  5. #5
    i have KBLC-240D

  6. #6
    should i have continuity across motor + motor - coz i have ? dont think thats right

  7. #7
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 19 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,831. Received thanks 192 times, giving thanks to others 5 times.
    Excellent, a UK supplier for the board I need!

    Provided you're aware of the voltage issue, and set the board right, then that shouldn't be an issue.

    I'd double check that you've got everything wired up correctly (i.e. the motor is connected to the armature terminals, and not the field terminals...)
    Failing that, I'd be contacting KB to see what could cause the resistor to blow.

  8. #8
    At the max ratings of 17amps that resistor will see 52 watts, maybe its too high a resistance!

    peter

  9. #9
    thats the resistance KB recomended for my motor .18 ohms
    but another company recomended .035 ohms

    i have some kind of breakout board attached to this controler i seem to be getting continuity across the +/- motor connections
    on the breakout board for the speed controler but if i test the motor terminals on the main speed controler board i dont get continuity
    which leads me to think i have a short on the break out board
    Last edited by Scott; 03-11-2010 at 09:31 PM.

  10. #10
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 19 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,831. Received thanks 192 times, giving thanks to others 5 times.
    ptwj's calc is correct for the starting current.
    Power = Current x Voltage, and to get Voltage drop across the resistor, we use Voltage = Current x Resistance

    To get Voltage over the resistor, we use Voltage = Current x Resistance, which is 17A x 0.18 = 3.06V
    Power = 17A x 3.06v = 52.02W.
    For running at the continuous rating, 0.85A x 0.18 = 0.153V x 0.85A = 0.13W
    For running at the intermittent rating, 1.75A x 0.18 = 0.315V x 1.75A = 0.551W
    For startup.......................................17A x 0.18 = 3.06V x 17A = 52.02W

    However, that is the instantaneous power consumption at switch on at full power. The KBIC should slowly ramp up to the set power, to avoid any major inrush issues.

    Quote Originally Posted by Scott View Post
    should i have continuity across motor + motor - coz i have ? dont think thats right
    What do you mean across Motor + Motor?
    On the board, or the motor itself?

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