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I'm definitely an amateur hobbyist, but I need to fix something for a friend.

I have a existing DC motor and the controller is shot. The motor is rated at 0-90 VDC (5Amps)

I wanted to see if this controller would work.

http://www.batteryspace.com/dc-motor-controller-electronic-speed-controller-kit-for-90v-dc-motor.aspx

It is rated at 6 amps (Max). Will this cause any problems with the motors? They will mostly be running quite slowly.

I eventually want to replace the pot with an Arduino.

EDIT Here is the motor. Its old. Can't find any specs other than what is printed on the label. http://www.lakecityelectric.net/show.php?motorid=20813

enter image description here

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  • \$\begingroup\$ Please share a link to the motor itself, to make it easier to provide a definitive answer. \$\endgroup\$ May 2, 2013 at 14:27
  • \$\begingroup\$ That sounds good from the information you've given. \$\endgroup\$
    – pjc50
    May 2, 2013 at 14:38
  • \$\begingroup\$ I shared a link to the motor. Thats all i could find...its like 20 years old. \$\endgroup\$ May 2, 2013 at 14:42

2 Answers 2

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The controller you have identified will work.

However, bear in mind that this controller is NOT providing any isolation from the line voltage. This is risky enough with the control potentiometer shown -- its internal insulation needs to be rated for this type of application, and many inexpensive units are not. But if you eventually want to control this with an Arduino or other microcontroller, it will be up to you to provide the necessary galvanic isolation.

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  • \$\begingroup\$ When you say "risky", risky how? How can I provide the Isolation? \$\endgroup\$ May 2, 2013 at 15:27
  • \$\begingroup\$ Anything you connect to the potentiometer terminals on the motor controller will be "floating" at line voltage, and must not be exposed for anyone to touch, nor connected to any other equipment (such as your PC). The method of providing isolation would depend on exactly what you intend to do. \$\endgroup\$
    – Dave Tweed
    May 2, 2013 at 15:38
  • \$\begingroup\$ This is a Rock Climbing tread-wall. I want to get it working again by just using the pot. Then once it's working, use a Micro-controller to replace the POT. Phase one, users will be turning the pot to get their desired speed, phase 2 will be using a digital pot and a Micro-Controller. I've done a lot of small projects with aurduino but this is definitely a learning opportunity for me. Any help you can provide would be great. \$\endgroup\$ May 2, 2013 at 15:43
  • \$\begingroup\$ A mosfet would do it, right? \$\endgroup\$ May 2, 2013 at 16:29
  • \$\begingroup\$ No, not by itself. But you could probably come up with a way to drive its gate via an optoisolator of some sort. It'll probably require reverse-engineering the motor controller's circuitry a bit to understand exactly what the manual potentiometer is doing. \$\endgroup\$
    – Dave Tweed
    May 2, 2013 at 17:39
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Motor you have is 0.5 HP or about 372 Watts. Recommended use for the controller is for 36Watts motor.

http://www.batteryspace.com/dcmotorheavyduty90vdcmotor36w2000rpm.aspx

  1. Start up current spec. for the motor is missing.
  2. Recommended use is for 36 Watts but as its is noted by you, it also specifies suitable up to 350 Watts. This is little confusing.

In absence of complete spec. for motor, you can consider these points along with electrical isolation issue pointed out by Dave Tweed.

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  • \$\begingroup\$ Where did that come from? \$\endgroup\$
    – Dave Tweed
    May 2, 2013 at 15:39
  • \$\begingroup\$ Motor spec has rating as 0.5HP. Controller spec. has link for "Perfect use to control MT-5400 90Vdc 36W motor". \$\endgroup\$
    – mj6174
    May 2, 2013 at 15:42
  • \$\begingroup\$ That may be, but the specs are also fine for the OP's motor. \$\endgroup\$
    – Dave Tweed
    May 2, 2013 at 15:44
  • \$\begingroup\$ There is no spec for start up current. What are the chances that controller recommended for 36Watts motor works for one rates ~10x of that. Having said that, I agree, I shouldn't have made blanket statement. It is one point to consider. \$\endgroup\$
    – mj6174
    May 2, 2013 at 16:11
  • \$\begingroup\$ You should edit your answer to make that point instead. Then I can remove my down-vote. \$\endgroup\$
    – Dave Tweed
    May 2, 2013 at 16:13

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