Req Help - Jury rigging 2HP DC Treadmill motor


I have a treadmill with a blown controller board and I'd like to bypass the controller completely and just wire the motor directly to the AC power source (via the DC converter.) Is that possible?

I've worked with DC motors before that just have 2 leads (red and black.) Applying DC current directly to these leads results in the motor turning. However, this particular motor (rated @130VDC, 18 amps, 2.5 HP) has 2 blue leads in addition to the standard positive and negative leads. I'm not sure how those should be wired. Any advice or suggestions (besides buying a new treadmill) would be most appreciated!


Walt Stringer

Reply to
Walt Stringer
Loading thread data ...

Perhaps they are sensing the RPM of the motor so there is effective control of the speed??

Reply to


Have you asked the company about the possibility of getting a replacement controller board? Are you sure the controller is blown and not just a fuse? This is a beefy motor, the AC/DC converter in the machine will not supply 18 amps, and even if it did work, this would give you one speed, which is not what you want from your treadmill. Motor control on a treadmill (a good one, anyway) is not as simple as putting x number of volts on the motor. With every step on the belt, the motor experiences a jump in load. As the motor ages, the controller must compensate to keep the speed accurate. By bypassing the controller board, you loose this closed-loop control.

-Good luck,


Reply to
Travis Hayes

Either that, or the 2 extra leads are for a thermal overload sensor.

My guess would be the overload, because a feedback tach would most likely have 2 different colored wires for polarity. A check with an ohmmeter (powered off) or voltmeter (while running) will identify them.

Bob Weiss N2IXK

Reply to
Bob Weiss

More than likely they are the field wires. 2 wires to a DC motor usually means it is a permanent magnet DC (PMDC) motor. At 2 HP, those are comparitively expensive. Most treadmills use field controlled DC motors for other reasons anyway. By controlling field strength the drive can become a "4 quadrant" drive, giving it the ability to handle the regenerative energy from your running strides wanting to drive the belt faster than the motor wants to move it. Without that, the drive would burn up from excess voltage.

Reply to

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.