/diy/ - Do It Yourself

the obvious place to salvage a suitable power supply is from another treadmill. not only would you get the power supply, but also the control electronics to vary its speed.

I suspect the power supply does not use any transformers, just rectified AC driving a PWM circuit to vary the average applied voltage. or it could be a custom switching supply, if the treadmill is high-end.

>>480141
Right right. I was going to mention that I know that this rest of this particular treadmill is unavailable, and I can't imagine where to find another one like it, since it's rare enough that I wouldn't imagine to see one turning up at a salvage yard.

there's always goodwill. i see a treadmill there at least once a month. prices vary $30-$90.

>>480139

Well, what are you using it for? If you can stand some accelerated brush wear, you could simply rectify and smooth 110V AC mains.

Otherwise you're going to need a fairly beefy buck converter.

>>480142

I see treadmills for free on CL every now and again. What exactly do you need the motor for? Since you have to convert the power anyway you might be better off just getting an AC motor of smiler RPM. Your motor is a 3hp at 4000 RPM. You can get 3 HP AC motor at 3600 RPM (3450 under load) as they are used in many types of larger power tools. Bigger tables saws are a source for them. I know a fair bit about power tool motors so just let me know what you need and I can help you out.

>>480139
get a bunch of heavy duty batteries, hook em in series, get a beefy potentiometer and a rheostat. bobs your uncle.

you can buy a brand new treadmill for the cost of those 7 car batteries. and your uncle bob wont be happy when the weight of the batteries causes the floor to give way, and land in his living room.

>>480164
3HP off of a single phase? Granted I live in an apartment but I don't think there are many circuits with enough amps left to power a 3HP motor unless you unplug your washer and dryer

>>480139
You can rewind the secondary from a microwave oven transformer to get the 30A you need but at a few volts. Use multiple modified microwave transformer secondaries in series to get the required voltage. Add a high current bridge rectifier on the secondary and a variac on the primary for DC voltage control.

>>480677

It depends. Modern efficient 3 hp motors pull about 13-16 amps on 110v systems. You can half that if you use 220 though. The question is, do you need a 3 horsepower motor? What do you plan on using this on? Variable speed drill press or something light that?

> Modern efficient 3 hp motors pull about 13-16 amps on 110v systems

your numbers dont add up: 3 HP = 2237 W but 16A*120V is only 1920 W.

however it's made in Taiwan, so maybe the horses are smaller there.

>>480760

Yeah, sorry, I fucked that up. Its 13-16 amps on 220 and 26-32 on 110.

Still, I can't imagine what he needs 3 horses at 4000 RPM for. If I knew what the use is I could recommend an AC motor that might fit his needs. As it stands I doubt he can find a 90 volt, 30 amp DC power supply. I doubt very much that the original power unit for that treadmill was supplying that much juice at peak output. It probably gave a much lower amount of juice and just let it come up to speed slowly. An instant burst of 4000 RPM was probably not something you'd want to see in a treadmill anyway. Well, outside of a YouTube vid.

>>480772
>Still, I can't imagine what he needs 3 horses at 4000 RPM for

It is a treadmill motor. So, it is for moving lots of weight. I'd turn it into a generator.

> So, it is for moving lots of weight

takes 3 horses to accelerate one fat american into run speed.