DC Tredmill motor HELP!

[jster1963]

Hi guys,

I know very little about electricity, and know less about how to make this DC tredmill motor work on my lathe.

I only have this motor without a power supply or controller. My goal is to run my mini lathe with variable speed. I have 2 questions.
1: Where can I get a power supply?
2: Where can I get a controller?

Now guys, my wife won't let me go "dumpster diving" for an old tredmill, or get one from Goodwill. I can't have any more "junk". Also, I am don't understand the "lingo" about PWM and the like. (I am trying and have read tons!)

So would you PLEASE explain things to me like you are talking to your 8 yr old son? Thank you in advance.

 

[OakRidgeGuy]

I can't help much either here.. but I do know that once you have it on there .. it will be awesome and your going to love it!

 

[DMS]

PWM is pretty simple when it comes down to it. It's the same principle your furnace works on at home.

In your home, your furnace is either "ON" or "OFF". If that thing is blowing air at 100F, you are quickly going to cook if you leave it on. You're gonna freeze if you leave it of. So what the thermostat does is to turn it "ON" then "OFF". It turns it on until the temp inside gets to what you set the thermostat to, then it turns it off until the temp drops below that.

PWM is basically the same thing. You have a motor and you want to control the speed, and you have a power supply at say, 100volts. If you hook the power supply up directly to the motor, it's gonna take off spinning at high speed (of course, it's going to take it a little while to get to speed, but that's gonna happen really fast, you will barely notice it). If you disconnect the power supply, the motor will coast to a stop.

So say the motor has a top speed of 1000 RPM. If we connect it to the power supply for 1/10second, it's gonna start moving. Disconnect it for 1/10sec. It'll keep going, but start to slow down. Connect another 1/10sec. Speed up, etc.

At that point, the motor will be moving at about 1/2 it's top speed (because the "ON" and "OFF" times are equal). That's what PWM is "Pulse Width Modulation". You "Modulate" (vary) the width of the pulse (the "ON" time) in relation to the "OFF" time. When the pulse width is 0, the motor is stopped. When the pulse width is 1/5 sec, and the off time is 0sec, then the motor is at 100%.

As far as a controller, you are going to probably want something called an SCR controller. You can usually find these surplus (check out allelectronics.com, or ebay). Ideally, you want to know what voltage that motor is rated for, but I would guess it is around 180VDC. So you can look for a controller rated at that, and at a corresponding current.

 

[jster1963]

PWM is pretty simple when it comes down to it. It's the same principle your furnace works on at home.

In your home, your furnace is either "ON" or "OFF". If that thing is blowing air at 100F, you are quickly going to cook if you leave it on. You're gonna freeze if you leave it of. So what the thermostat does is to turn it "ON" then "OFF". It turns it on until the temp inside gets to what you set the thermostat to, then it turns it off until the temp drops below that.

PWM is basically the same thing. You have a motor and you want to control the speed, and you have a power supply at say, 100volts. If you hook the power supply up directly to the motor, it's gonna take off spinning at high speed (of course, it's going to take it a little while to get to speed, but that's gonna happen really fast, you will barely notice it). If you disconnect the power supply, the motor will coast to a stop.

So say the motor has a top speed of 1000 RPM. If we connect it to the power supply for 1/10second, it's gonna start moving. Disconnect it for 1/10sec. It'll keep going, but start to slow down. Connect another 1/10sec. Speed up, etc.

At that point, the motor will be moving at about 1/2 it's top speed (because the "ON" and "OFF" times are equal). That's what PWM is "Pulse Width Modulation". You "Modulate" (vary) the width of the pulse (the "ON" time) in relation to the "OFF" time. When the pulse width is 0, the motor is stopped. When the pulse width is 1/5 sec, and the off time is 0sec, then the motor is at 100%.

As far as a controller, you are going to probably want something called an SCR controller. You can usually find these surplus (check out allelectronics.com, or ebay). Ideally, you want to know what voltage that motor is rated for, but I would guess it is around 180VDC. So you can look for a controller rated at that, and at a corresponding current.

THANKS, I really understand that now! I will check out that site. I'm hoping I can "plug and play". I have soldered things before, but I followed very detailed instructions. It's not something I really understand. Thanks again and wish me luck......

 

[Chucketn]

Re: DC Treadmill motor HELP!

jster1963,
Look on the internet or E-Bay for a KBIC controller, these are probably the best. They require a power resistor based on HP. The seller should allow you to pick the needed resistor. I would go for 1.5 HP resistor, Chinese horses are a bit smaller than everyone else's.
Speed control is by a 5K or 10K pot, don't remember which. You will need 2 toggle switches, a single pole single throw (AKA SPST) for off and on, and a double pole double throw (AKA DPDT) to make a reversing switch. Wire the end terminals of the DPDT in an x to the opposite end terminals, power + and_ in at the middle terminals and out at either of the end terminals.



Failing a KBIC controller, look for a MC-60 treadmill controller. They are about 4"x5" and mounted on a large aluminum heat sink. These are simple controllers and are controlled with the switches above and a 5K pot for speed. I have one running my X2 mill and one on an arbor with wire wheels.

Chuck

 

[Pacer]

Get on ebay and do a search for "DC motor speed controller" and that will cover many choices -- like this one (that is a good price on one) - they will typically run in the $50 to $100 (and up) range. The under $20-25 range ones require DC input and you will want one that changes AC to DC...

http://tinyurl.com/c9onx3s

Thats a nice motor youve got, most of them has a flywheel pulley taking a grooved belt and can be a bit of a pain to adapt, but youve already got a conventional V belt...

 

[jster1963]

Re: DC Treadmill motor HELP!

jster1963,
Look on the internet or E-Bay for a KBIC controller, these are probably the best. They require a power resistor based on HP. The seller should allow you to pick the needed resistor. I would go for 1.5 HP resistor, Chinese horses are a bit smaller than everyone else's.
Speed control is by a 5K or 10K pot, don't remember which. You will need 2 toggle switches, a single pole single throw (AKA SPST) for off and on, and a double pole double throw (AKA DPDT) to make a reversing switch. Wire the end terminals of the DPDT in an x to the opposite end terminals, power + and_ in at the middle terminals and out at either of the end terminals.

View attachment 43771

Failing a KBIC controller, look for a MC-60 treadmill controller. They are about 4"x5" and mounted on a large aluminum heat sink. These are simple controllers and are controlled with the switches above and a 5K pot for speed. I have one running my X2 mill and one on an arbor with wire wheels.

Chuck

Thank you very much! You are over my head on a few things. I will start the research tonite. I'll keep you posted. Thanks again......

 

[jster1963]

Get on ebay and do a search for "DC motor speed controller" and that will cover many choices -- like this one (that is a good price on one) - they will typically run in the $50 to $100 (and up) range. The under $20-25 range ones require DC input and you will want one that changes AC to DC...

http://tinyurl.com/c9onx3s

Thats a nice motor youve got, most of them has a flywheel pulley taking a grooved belt and can be a bit of a pain to adapt, but youve already got a conventional V belt...

Thank you so much! This stuff is a little over my head, so I'll research this starting tonite. Thanks again.....

 

[outsider347]

This is what I did & it works great on my drillpress...

For Free
or
maybe 50.00, find a used treadmill on CL

save the motor, the controller, speed control potentiometer & knob, & all the connecting wire's to make it work. Save the belt & cut it up to line your tool drawers. I saved the usable metal for future metal projects. scrap the rest( pretty good $$$ for scrap metal)

like I said, you can do this for free or maybe 50 bucks & your time of course

fun proj

 

[amuller]

A couple of things to keep in mind:

That motor looks like it's intended to have an external fan on the brush end. You will need some sort of airflow for continuous use. If you have the fan that likely came with it, use it and put a shroud around it.

Open permanent magnet motors can be a problem around tools if metal chips get into them--chips will stick to the stator magnets and eventually jam things up. So try to protect the motor from that.

The label doesn't seem to say anything about rpm. Hopefully you can dig up some specs online.

Good luck with the motor!