View Full Version : Got a treadmill motor,now what?

Bob Fisher
06-18-2012, 10:11 PM
Picked up a Treadmill from the garbage today, stopped it down and now have a 2hp DC motor and controller and some other bits. I am thinking about salvaging the multi groove pulley by removing most of the flywheel and using it to drive my 9X20 Jet lathe. If anyone has done something similar, I am totally open for ideas. The flywheel has what appears to be 1/2-13 LH threads, if I were to lo Locktite the pulley to the shaft, would it be OK to power the Lathe in both directions? Thanks for any thoughts, Bob.

06-18-2012, 10:25 PM
I'd either ditch the flywheel or make some form of positive attachment.

06-18-2012, 10:28 PM
You want to turn as much of the weight off the flywheel as possible.
One problem with the controller used in T.M.'s is that many require you to take the speed control back to zero every time you start and/or the accel and decel is very long duration.

Bill Pace
06-18-2012, 10:39 PM
I have adapted some 5-6 machines/tools to use treadmill motors and I used the existing flywheel doing as you say and cutting the center out and adapting it to the various situations I was working on. I used a set screw on the couple lathes I did where I would occasionally use it in reverse.

Mike Amick
06-19-2012, 01:22 AM
just reverse the leads .. no problem.

You may want to play with it a bit .. and .. see if the condition Maxheadroom
mentioned exits. I have/had a bunch of these and some are really bad ..
like it takes literally 6sec before the motor starts turning. I had it hooked up
to a bandsaw and then removed it .. because it felt like forever sometimes.

All over the net you will find guys looking for a solution to the
"having to turn the speed control all the way to zero .. then back up"
to get it started problem.

I have tried having power to the controller and switching the voltage
going to the motor. It like fries the contacts everytime. Must be some
vicious current there for a sec.

Luckily .. not all the controller do this .. so .. check yours.

it will keep a more constant speed WITH the flywheel .. just cut the
splined part of it off. ...or .. You may not need the flywheel depending on
the application.

This must be treadmill month .. lots of interest. cool

Forrest Addy
06-19-2012, 03:02 AM
The controller from the treadmill is a PITA to alter the accel and decel. A few have but they knew the resistors or whatever to change.

If the budget will stretch use a Dart or a KB control. These general purpose controls have adjustable accel a decel plus max and min seed reference padding. The KB 125 will run the motor to full ratings at full RPM if furnished with a heat sink - if plugged into a 20 Amp 115 volt outlet.

Here's a link to a KBcontrol such on eBay


This is a fair price for NOS in the box. It seems fully complete; the photo shows the speed control pot and spade tweminals in a bag under the flap. It's visible in the opening.

Most machining operations won't require full RPM so the heating effect of acual Amps drawn will seem less (as a proportion of actul Amps to FLA) to the motor protection device.

Think this project through so you get the pulley ratios right. The flywheel is unnecessary for use on a machine tool however it incorporates a fan to draw air through the motor. The air flow may be necessary but the rotating inertia is not. It's that much more mass for the motor/drive to cope with for instant reversals like when machine tapping.

Here's a couple links on this topic:



06-19-2012, 10:12 AM
There is a Baldor BC200DC on Ebay for 90, so far no bids!
This is the higher end 4 quadrant drive which has the regenerative braking and can be reversed by the pot command with no armature switching, if required.
Baldor are re-labeled KB, just a different P.N.
I have modified some TM controllers to eliminate the slow start, but it takes some reverse engineering and time!

Bob Fisher
06-19-2012, 11:42 AM
Thanks for the replies, I am not married to the speed control, I have a new in the box Leeson controller that should work. I have just noticed a broken resistor on the circuit board anyway. The Leeson has a 90/180 VDC switch, the motor is rather at 130VDC. Witch setting would be the best? I would suspect that the 180 could over rate the motor. The pullieys that were on the TM give me a ratio of 2.5 to 1, which would give a top speed of about 2300rpm,just about right for a 9X20.I also have a 10 X24 Logan so downtime is no issue. I have grown to like the clutching feature on the 9X20,rather than turning the motor off to measure,and would like to keep it. Any thoughts?Bob.

06-19-2012, 11:59 AM
Volts = RPM with a dc motor. My KB is a chopped sine wave SCR controller
so cogged badly at lower RPM and being limited to 90V and "1.5HP" with
heat sink began cutting out at higher RPM with a TM motor rated at "2.5HP"
at 130VDC drawing 17A per the label. KB controllers tend to choke even
at 90V much above 12A or so. YMMV. The Leeson is a better idea, more
stoutly rated and will need 220Vac input for the 180 output. If it is a pwm
you just set the max pot so it won't reach the full 180V. Most TM motors
are screamers at full input with RPM in the 5-7K range. The Leeson output
at 90VDC will likely cut the max HP of the motor in half, but on a 9x12 that
may not be a problem. An external muffin fan bolted to the end of the motor
would be a good idea and putting a good chip shield also as any ferrous chips
that glom onto the PM through the wide open vents on the end are not coming out.

06-19-2012, 12:30 PM
KB call their PWM KBWT types whisper drives, they are much smoother over the SCR models and also prolong brush life.
Because using PWM they will go to either 130vdc or 260vdc.

Forrest Addy
06-19-2012, 01:45 PM
Max. I looked up the KBWT drives but they are rated at 6 to 12 Amps depending on model and the treadmill motors - the larger more desirable ones - are rated 16 to 20 Amps.

I emphasize there is no problem using the KBWT drives with a beefier DC motor. The motor will function normally right up to the full current capacity of the KBWT drive. Thereafter the drive will current limit protecting itself. I only mention it because some may need to run the motor to full loads

06-19-2012, 02:12 PM
The ideal is to pick a A-M-C servo drive, either DC or BLDC both will run a DC brushed motor, the AC suffix denotes a built in P. Supply.
e.g. ebay 270997042634, sometimes a deal can be found for the odd one.
All the features of a servo drive with bi-directional control etc.