Thread: Wow - huge price difference

Well guys I can report we have lift off - the tacho is looking good Huston.

After smoking the optical sensor I wondered if the two wire Hall switch would work.

No problem what so ever - hooked it up and going fantastic.

He He and I'm only a bunny when it comes to these things

I've been playing around with the number of magnets to use to give a stable reading at low speed and 8 looks about right.

So I will now modify the optical wheel for magnets and we are good to go.

Cheers all

Rob

My tacho turned up today......but I think I have a dud. Nothing on the screen with 12v attached......

Good news too though, went to the tip shop this morning and got 2 treadmills for $20. Both 180v dc, one 1hp and one that states 6 amps 1.5/3hp ?

G'day Ewan,

6 amps could be 1.5 HP but hard to say until you take the cover off. My 2 HP had a 7 amp AC fuse.

Interesting to see the recommended KBI controller fusing is way higher - 15 amp for 240 AC and 10 for the 180 DC with a 2 HP motor. So the treadmill motors can't be working very hard.

Also read a very interesting article on torque v's speed of DC motors.

Maximum power is at 50 - 60% of rated motor speed. The controller max speed is set at this % out of the box. This would also make the brushes/commutator last a lot longer.

A dud is a bit unlucky re the tacho.

But the motors sound good - what brand were the treadmills ?

Cheers

Rob

Hi Rob,
Good to hear you got the tacho working.

One treadmill was an Advanceachieve, it says on the outside "3hp peak power" or something to that effect. Sure is lots of goodies to be had once you pull them apart! The motor on this one is the strange one, 180v, 6amp, made in china, but in the HP box it says 1.5/3hp? 6 amp at 180v is about 1.5hp.....so i don't know where the 3 comes from. The other big score in that treadmill is a nice big ally heatsink, bigger than the board itself!

The other seems to be brandless a Proteus, although they were outside so it may have lost its stickers. It has a 4 amp 1hp made in Taiwan motor, and a rather nice ally box section frame.

I'll post a pic of the motors specs when i get home.

Gee you got those motors out quick.

Interesting. See here re HP ratings : http://www.dickssportinggoods.com/in...egoryId=222960

Has a nice big cooling fan on the end. The hard part is having enough shaft length to keep it when you use it for other duties.

Yes my 2 HP one had a massive angle section aluminum heat sink - which I'm hanging off of the controller.

You do realise of course that both treadmills will have a rotation sensor of some sort on the front roller or the motor. Yeah, there's gold, gold I say, in them thar treadmills.

It might even be....dare I say it...........optical .....heh heh

Good one Ewan.

Cheers

Rob

Both treadmills have/had 2 wire HE sensors on the front roller. Into the electronics bits bin with those......I have several computer fans and cpu heatsinks so i think i'll just do what you did with the fans. I'd like to get two pulleys on the shaft so space will be at a premium.

Good news on the tacho, turns out it simply didn't like sharing the plug pack i was using with the oscilloscope. Reads the pulled up HE signal fine. No problems with only one magnet at 30rpm (my current bottom speed)either, not sure why you need 8 Rob?

Anyone else got a clue to the 1.5/3hp motor, Ray, are you reading this?(help, i have no idea....and i feel i should)

Thanks for the link Rob, that pretty well explains it.....but i would not have thought it would have been 200% of the base HP.

Good news on the tacho Ewan. Good to hear it's a goer.

I played around with the lathe at 120 RPM with one magnet and it seemed to vary on the reading a bit - but I was hand holding the Hall unit.

Added more magnets and it seemed to be better - more stable reading.

I will mount the sensor properly and try it again - might be overkill by me. I've got lots of smallish rare earth magnets and thought more would be better.

A bit more tinkering tomorrow.

I had considered making the electric fans switchable so I could run them when the motor was off to cool it down fast if things got a bit too warm. Have to see how temperatures go first, but it could be handy. The current idea is that the fans and tacho come on when the motor does, and that I run it all off of the existing magnetic safety switch on the lathe.

Interesting stuff.

According to that link I provided the 3 HP rating is a peak rating that the motor can sustain for a short time. The continuous rating is 1.5 HP.

All I need now is for the thermal paste to arrive for the heatsink and it will be full steam ahead on the conversion.

Rob

I only saw the link after i posted Rob.....did you add it or am i going nuts (again)?

I was going to hook the tacho up to run once the lathe had power, same with the fans, so they will run when the motor is off.....but i will put a simple thermistor temp switch in to control the fans. I know Jaycar do a kit but its $35 odd dollars.....KitStop electronic kits and modules for hobby schools and industry - Temperature Sensing & Control thats about the cheapest i can find. I can send you the schematics for one or make you one if you want. I'll be making myself one so making 2 (or more if anyone else wants one) won't be hard.
Did i PM you my address for the controller? Can't remember. If you want to send me a total cost etc and i'll fix you up for it.

Yes, I added it. I'm a chronic editor - comes from years of document drafting - can't help myself

I don't have your address Ewan, but I see you're in Canberra so I can work it out from there.

I will have to see what the current rates are. I believe they've changed them recently. The controller is fairly small so it should be on the low end of things.

I will get back to you on it.

A temperature switch is an option I hadn't considered. The two 92 mm PC case fans I'm using move quite a bit of air so that might be enough. Will have to see how it all works out.

Regarding the motor shaft length, you could easily turn up a pulley with some overhang so it extends past the end of the shaft - my existing motor pulley is like this.

One reason why I put the fans on the rear of the motor is because the diameter of the original fan was way too big to fit the available space in the belt drive enclosure - and it wasn't a particularly effective fan anyway.

Cheers

Rob

Hi, looks like I'm not the only one collecting treadmill motors My plan is to put one on my drill press so that I don't have to muck around with changing belts all the time. I've got the following DC motors a 1 HP 180 v (the strangely named Turdan), a 1.5 HP 180 v (Proteus) and most recently I picked up a 2 HP 250v York. The controllers for all but the Proteus are shot and I've been looking at getting a replacement controller, either the KB direct from the US via eBay or this one that would suit either of the smaller motors.

Treadmill2.jpg

I had seen those small cheapo controllers on Ebay.

Be interesting to see how they would go, but I suspect they will cook - the maximum amperage is way below what the treadmill motor will draw under full load.

The heatsinks look like something out of a PC power supply.

Baldor recommend 15 AMP AC fusing for 2 HP , so you can work it out from there.

Rob

Yeah, those el-cheapos sure do look a bit light on and I've been a bit hesitant to give one a go. But the price is pretty tempting... so I might order one and if the SCR fries using it for the drill press, I will repair it and use it for a lighter load application.

So blu, your the reason I couldn't find any good donor treadmills......LOL

Just had a rather interesting play with the two wire "he" sensors from the treadmills. I get nice clean square waves,even when looked at sub 10ms. However the tacho jumped around from 200 to 2000 and every thing between. I went to four magnets and it is better, running a range of only 200 rpm, but still a long way from steady. I tried a pull down resister but it makes no difference, it only cleans up the ground signal. I am wondering if the sensors are not actually reed switches and my "toyscilloscope" is just nog good enough to see some shuddering as they turn on and off.

Edit. I just managed to snap the waveform as it came down at .1ms. It takes around 1ms to come down, ill go check the HE sensor now.

The HE sensor takes about 20us to turn off, way way way faster than the treadmill sensors.

I'd say its a bounce problem as the tacho can't make up its mind as to were the signal actually stops?

G'day Ewan,

Same result here with the two wire sensor.

Even with lots of magnets, once you get into the sub 200 RPM range it's all over the place. I played around with the sensor all morning and have written it off. Pity.

Moved on to machining up/adapting a bigger pulley for the motor. I did my calculations on the max speed of the motor, but that is not the way to go. It's better to run at 60% and use the torque.

So I've jumped up the motor pulley size considerably. I can still use the intermediate and spindle pulleys to gear down the motor and get even greater torque in the sub 100 RPM range if I want it.

Days aren't long enough

Re-work is a bit annoying, but when you adapt stuff it's just part of the on going thought/learning process.

Cheers

Rob