Circuit to control/test a treadmill motor

[Savage99]

hi folks
My neighbor gave me a treadmill. The top electronics got wet and damaged. It appears as though the motor is in good shape and the elevation mechanism is in good shape as well. I have taken everything down to just the bottom with the motor and the roller it is attached to via a belt set-up. The other roller I will attach to the metal work depending on the size of PVC I can find. I am wanting to make a "universal" tumbling type cleaner for items other than brass, both wet and other media. Anyway, where is a circuit to control the speed of the motor to be usable and how do I power this motor? thank you. Hopefully I put this in the right section. I am somewhat able to build circuits and have an old computer power supply that I thought might help with this, or I might use this power supply for a PID, who knows. I have the tumbler idea in my head and I may not have put things done right so hopefully you all get what I am trying to do. The treadmill is an Nordic Trac C2100. A diagram I have does not show to much.
The motor has black, red and 2 blue wires. Do I need to put all of the info from the label on the motor?

[MaryB]

Most of those are DC motors so simple voltage control will usually suffice for speed control. Could try it on 24 volts... think they are 120 volts factory. A pic of any motor markings would help to tell if it is AC(some are) or DC(most are)

[30Carbine]

You need to know AC or DC on the motor. you can use a dimmer switch to control both I have used them for both no problems. the only problem you might encounter is the pc power supply some of them don't produce enough amps to run a DC motor with out over heating and tripping the breaker on them. been there done that. the last one I tore apart was 120 volt it had a converter in it. the motor it's self was 24 volt DC so I rigged it up to work as the power supply and used a dimmer switch to control speed. I use this one as a spot trommel at one of my claims here.

[oldred]

Treadmill motors are DC and I doubt any of them can be run (at least safely) with a light dimmer since most are at least 1 HP, just too much current draw. If you just need one speed then you need a power supply of the voltage that will give the desired speed and with an AMP rating high enough to supply enough current. If you want variable speed, or even just a constant speed, then there are some killer deals on motor speed controllers on Ebay but whatever you decide on make double SURE it's AMP rated higher than the motor current draw! If you are unsure then ask an electrician, this is simple enough once you get into it but under-rated components will not only burn out quickly (sometimes instantly!) but you could easily start a fire!

[popper]

it's AMP rated higher than the motor current draw! Higher than stall/startup current! Usually about twice running current.

[ProfGAB101]

Thread mill motors usually have a fan impellor to cool them - if they are run to slow or any of the surrounding ducting and coverings are removed or modified the fan will not cool the motor properly - a common workaround is to get a bathroom vent inline duct fan to cool the motor continuously. Using a light dimmer for anything other than lighting is WECSOG Stupid! If you do want to try a speed control buy an inline woodworking router speed control - it is designed to be able to handle the load. Again those are for universal AC motors and most tread mills are DC. A DC motor will rotate at a speed ratio to voltage but will begin to turn with under 1 volt - A "D" cell battery should do it.

Keep in mind at full power say maybe 90VDC @ 30 Amps you are in arc welder power levels, wiring needs to be of proper gage even for short runs.

Some treadmill motors have the brushes mounted at a slight angle, these motors are intended to only turn one direction. Motors that the brushes are perpendicular to the shaft ( in 2 planes ) can run both ways by reversing the polarity.

Biggest DC motor I service is 40HP 380VDC and has 8 wires feeding it, each wire has 22mm of copper under the insulation. It is an 8 brush motor made in Germany. The power supply is the size of a large refrigerator.

[ABluehound]

Most electronics board components are designed to be cleaned in something like a dishwasher with special soaps and water. The fact it got wet will not necessarily kill it. Provided it has not had power applied to it wet and the magic smoke escaped from the little bits. My Iphone spent ten minutes at the bottom of a 500 gallon aquarium when it fell out of my pocket (while turned on even). To save it I removed the back, unplugged the battery and spent 45 minutes with the air compressor drying it out (@5 psi). Same basic thing applies here, dry it out with compressed air. If it has a thin membrane touch pad you may be able to save it by storing it in a sealed bag with desiccant or even rice for a few days. I wouldn't re-invent the wheel.

Electronically adjustable speeds are easier to accomplish on an asynchronous single phase AC motor. Cheap sewing machines use something called a carbon pile which is a stack of carbon discs with one of the two AC lines interrupted by a stack of carbon discs connected by an electrode on each end and when the discs are mechanically compressed together more current flows through the pile and the motor runs faster this is limited by the size of your carbon pile. A higher quality speed control can be made with a high current SCR or a DIAC in a simple circuit cutting the duty cycle of the sine wave of the alternating current to adjust the speed. Really, for what your looking for running an AC motor with 120 VAC at its natural designed speed and using a couple pulleys to set your speed is much easier and takes less engineering and gives you the best results for the dollar.

All motors make heat when they do work, a DC motor run at a low speed without proper cooling will become dangerously hot fast.

If you are looking to make a monster tumbler you may be better off robbing a washing machine off the side of the road of its motor and pulleys to set the running speed (and maybe the drum). A motor from a washing machine is likely a squirrel cage motor rated for 1,500 RPM at 1/4 to 1/2 HP. It should have a internal fan and be designed to run for long times without overheating if it is lightly encumbered. A washing machine motor will have have a small pulley on it inside the washer will be a shaft with a larger pulley going into the transmission take that as well and mount on the drive shaft of your tumbler. A 1/3 Hp washing machine motor with stock pulleys you take with it should be good for 50-75 lbs of load in your drum provided you do not carried away making the drum turn too fast. There is likely to be a starting capacitor with the motor you will want to keep with it. If the drum speed is too slow direct drive (or if it slips) you can fatten the shaft up with a bit of duct tape where it touches your drum. I have seen some very inventive ideas for home made drums too.

[jmorris]

As you can see by the responses there are more than one type of motor and it is speculation without information about the motor in question.

[abunaitoo]

I wonder if something like this might work???
http://www.ebay.com/itm/DC-5A-12V-24...item41948c55a1

[bangerjim]

I have two of these on machine tools (2 wood lathes) and the work GREAT. 90VDC. Continuous rock solid variable speed...........almost as good as my 220VAC VFD's.

The circuit board is not just a power supply!!!!!! It has sophisticated speed/current sensing circuitry that maintains torque AND RPM's under any load. The motor is just a hunk of magnet and wire. The key to the system is the CONTROL BOARD!!!! Without it, you have an uncontrolled RPM load dependent variable torque motor that is really not useful for anything except at full 90VDC solid REGULATED (key word) power.

Depending on the amp draw of the motor, you can mabe get one of the control packages from littlemachineshop.com to work. But they are not cheap! I would sure try to dry out and clean that control board you have!!!!!

This would NOT be a good choice for a tumbler, as it 1) has brushes, and 2) is not made for continuous usage. Get a shaded poll or a standard frame capacitor start appliance/tool motor (AC & no brushes & fan cooled) if you want something that will run for hours/days on end. And make sure is has it's own fan ventilation system for long-term operation.

That is why most buy a professionally designed & built media tumbler....they are designed and built to run for days on end. Mine is.

bangerjim