Info on building a VFD from a treadmill

[fourjeepin]

I have read here that this is possible, but I have never seen many details. I don’t have a need for a VFD, but I do have a donor treadmill that needs to go away.

Anyone know how to go about this? And anyone in the Atlanta area interested in a treadmill?

 

[Packard V8]

Yes, BTDT. It's all over the internet. Makes a perfect drive for drill press.

jack viens

 

[454ragtop]

Probably not a VFD, more likely it's a DC motor and controller. Does make a good variable speed drive if you can work with the controller, and the motor shaft size/design is workable.

 

[Packard V8]

Probably not a VFD, more likely it's a DC motor and controller. Does make a good variable speed drive if you can work with the controller, and the motor shaft size/design is workable.

For true. I was lazy in my answer. Most treadmills have a strong 90-volt motor and speed is controlled by varying the voltage, not the frequency.

For those who like a challenge, a treadmill DC motor is perfect for DPs. However, one local guy and his wife are still mad at me. He saw my installation, bought a used treadmill but evidently even disassembling it was beyond his skill set. I kept getting calls with the most basic of questions. Finally, his wife got impatient with the frame and tread in her garage and he paid to dispose of the remains at the local Waste-to-Energy facility.

So yes, it's not difficult, unless it is. There are dozens of how-to threads and youtubes on the net.

jack vines

 

[redm18]

You will not make a VFD from a treadmill it's not possible. A VFD is a device that allows you to run 3 phase electrical devices (ac motors) on single phase power. Typically industrial machines come with 3 phase motors and 3 phase power is typically only available in an industrial area. The added benefit of a VFD is that with a 3 phase AC motor you can have some control over the speed that the motor runs at by changing the frequency that the 3 phase power is output at. This can be extremely handy for something like a drill press or band saw where you might want to speed up or slow down the tool dependeding on the material being drilled or cut. A treadmill typically will have a DC motor that you can control the speed with a control board and people have harvested the motor and control board to use on a drill press. My understanding is that this can be a cheap way to get a variable speed drill press if it works out but as mentioned above its not always an easy or strait forward project and not all treadmills work the same way. I think this used to be a much more common project before VFD's prices have dropped to the level that they are affordable for the common hobbyist.

 

[Packard V8]

You will not make a VFD from a treadmill it's not possible.

Yes, No, Maybe. Read this.
http://www.vfds.in/variable-frequency-drive-in-treadmill-424237.html

A VFD is a device that allows you to run 3 phase electrical devices (ac motors) on single phase power.

That's too limited a definition. There are literally infinite combinations of VFD input and output. There are VFDs which only accept 3-phase input.

As long as we're being precise in our technical terminology, a Variable Frequency Drive does exactly that; changes the frequency of the incoming electrical signal to whatever frequency variables the internals allow for output. For some motors, changing the frequency input produces an equivalent rotational speed.

Some, but not all VFDs, also have the capability of changing 240-volt single phase input to 3-phase output as well as varying the frequency. Some, but not all, have the capability of changing 120-volt single phase to 240-volt 3-phase, as well as varying the frequency.

So, when selecting a VFD, read the fine print. There are too many horsepower, voltage and other requirements to just grab the first one which pops up on an internet search.

jack vines

 

[matt_i]

In broad strokes:

A VFD (medium electronic module) is a speed controller for an AC motor, and it must be a 3 phase motor. Up to a certain point either single phase AC or 3 phase AC can supply input power to the VFD.

A DC-drive (looks like a circuit board with some heat sinks) is a speed controller for a DC motor. Typically single phase AC input unless talking monster sized stuff.

Typically a treadmill doesn't cross into the price-point where integrating a VFD and an AC motor would be feasible. Also VFDs typically have a distinct "whine" (its a sound) that some people might find undesirable while walking or running on the hamster-belt. The DC motor is pretty quiet.

 

[6PTsocket]

For true. I was lazy in my answer. Most treadmills have a strong 90-volt motor and speed is controlled by varying the voltage, not the frequency.

For those who like a challenge, a treadmill DC motor is perfect for DPs. However, one local guy and his wife are still mad at me. He saw my installation, bought a used treadmill but evidently even disassembling it was beyond his skill set. I kept getting calls with the most basic of questions. Finally, his wife got impatient with the frame and tread in her garage and he paid to dispose of the remains at the local Waste-to-Energy facility.

So yes, it's not difficult, unless it is. There are dozens of how-to threads and youtubes on the net.

jack vines

Tread mills do use a DC motor but the control board does not vary the voltage. Low voltage for low speed equals low torque. They do it by PWM modulation. The full DC voltage is turned on and off to make a series of pulses. The width of the pulses controls the speed. At full speed the off time between pulses is zero, constant DC. With a high enough pulse rate the motor runs smoothly even when the power is off a lot longer than it is on.

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