trying to get an MC60 controller and a treadmill motor working on my 14-inch bandsaw

Discussion in 'The Projects Forum' started by ljbix, Mar 7, 2015.

  1. ljbix

    Thread Starter New Member

    Oct 14, 2014
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    I'm trying to get an MC60 controller and a treadmill motor working on my 14-inch bandsaw (Grizzly G0555LX). I replaced the original motor with an idler and pulley, with a belt to the treadmill motor. The pulley ratio between the motor and the idler is 3.2:1 so that when the motor is turning 5760 RPM the idler shaft (old motor shaft) is turning 1800 RPM, roughly the speed of the old motor . The flywheel that was on the motor on the treadmill has been removed and replaced with an aluminum pulley.

    At high motor RPM when I load the saw even a little bit I get a speed oscillation that cycles at around once per second or a little faster, between applying power and cutting power off. I have to back the speed way down to get the oscillation to stop. Have you run into this on your setup? Is your MC60 controller 'stock' without modification? My thought is that all the extra inertial load on the motor of the bandsaw wheels is putting the MC60 speed control loop into an unstable region and that somehow the speed control loop compensation on the MC60 needs to be modified. But maybe it is something else tripping inside the MC60 controller. All the LED's on the MC60 seem to be behaving, and I don't see the current limit LED or the SCR trigger LED turning on or off during this oscillation.

    Have you noticed any oddities about using the MC60 controller on your bandsaw?

    Jim
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC, but you have hijacked someone else's thread (an old one at that!). You are more likely to get help if you start your own thread.
     
  3. bertus

    Administrator

    Apr 5, 2008
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  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I suspect the MC60 has a motor current sense resistor/circuit and this is repeatedly going into current limit as the load changes, I see in the schematic there is a .01Ω resistor in series with the motor for this.
    Unfortunately unlike the KB/Baldor controllers it is not adjustable.
    Max.
     
  5. ljbix

    Thread Starter New Member

    Oct 14, 2014
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    0
    Yes, there is a current limit detect/limit. The current limit LED is not blinking during the oscillation, which leads me to think this isn't the problem. Also, I'm using an AC power meter during testing and I'm only seeing 300 watts, or less than 3 amps average current. I have an isolation transformer that can handle this power and using that would allow me to use an oscilloscope to try to see what's going on, and I guess that's what I'll have to do next.
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    I moved your post here, as said you did hijacked the other thread and I moved them here.
    The other thread is closed now.

    Bertus
     
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