Nice but defeats the purpose of a cheap positioner motor sadly....I can see why they went so cheap now.
- Thread starter ukracer
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I quite like the idea of this one gaz1 posted to start with...http://www.ebay.co.uk/itm/HX-PWM-AC...601705?hash=item1c5bf0f2a9:g:d0AAAOSwwbdWMyZh
How do they work on a treadmill then...even I can walk on them...slowly.
I was hoping using a lower voltage they might fit the bill...still maintaining torque.
WorkshopChris
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With a 80mm drive roller it would be doing roughly 4 revolutions for every meter the belt rotates as you walk.
It the motor pulley is roughly 25mm that is about 3 to 1 ratio.
So every meter the treadmill belt moved the motor turns 12 times.
(hope that is close i am struggling with thinking tonight).
Maker
Most folk just call me; Orange Joe
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There's usually a pulley on the drive roller so the reduction is probably closer to 5:1, which means for every meter the motor turns 20 times.
If we assume the minimum speed of the treadmill is 3mph, that's about 80 meters per minute, so the motor will be turning at 80*20=1600 RPM for it's minimum speed, just a tad fast for a welding rotator
.EDIT; I don't really like that estimate, it sounds a bit high. I think the motor's I have are 4000 RPM and they came out of treadmills with a top speed of 12 mph, which gives 1000 RPM for 3 mph belt speed. Still way to fast for a rotator as is but with a suitable reduction a DC motor would be excellent as they provide full torque at a wide range of speeds.
skotl
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Technically, you can't get more DC out than the peak to peak (Vpp) in, rather than peak (Vp)Yeah it's the fact that AC is talked about in RMS.
You can't get more DC out than the peak volts in, is what I was trying to say - badly.
I'll stop now
gaz1
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ive come across these before so heres a link to something
As rightly suggested by one of the dedicated readers of this blog, Mr. Ivan, a 180 V treadmill motor can be simply controlled through mains phase chopping concept, normally incorporated in all commercial dimmer switches for regulating home fan speed.
Shown below is a modified dimmer switch circuit design which can be effectively used for regulating a 180 V treadmill motor from zero to max:
http://www.homemade-circuits.com/2013/11/treadmill-motor-speed-controller-circuit.html
you can also look on here as has a power supply reference for 110v
http://forum.allaboutcircuits.com/t...ower-supply-for-my-no-frills-treadmill.99271/
id advice reading this page
http://www.practicalmachinist.com/vb/general-archive/dc-motor-conversions-72811/
As rightly suggested by one of the dedicated readers of this blog, Mr. Ivan, a 180 V treadmill motor can be simply controlled through mains phase chopping concept, normally incorporated in all commercial dimmer switches for regulating home fan speed.
Shown below is a modified dimmer switch circuit design which can be effectively used for regulating a 180 V treadmill motor from zero to max:
http://www.homemade-circuits.com/2013/11/treadmill-motor-speed-controller-circuit.html
you can also look on here as has a power supply reference for 110v
http://forum.allaboutcircuits.com/t...ower-supply-for-my-no-frills-treadmill.99271/
id advice reading this page
http://www.practicalmachinist.com/vb/general-archive/dc-motor-conversions-72811/
nice info in that last article.
Cooling at slow speed will be rotten. Keep motor speed up.
Arrggg.
gaz1
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heres some info on another board
http://www.mig-welding.co.uk/forum/threads/any-electronics-wizard-in-here.69008/page-3#post-913587
http://www.mig-welding.co.uk/forum/threads/any-electronics-wizard-in-here.69008/page-3#post-913587
Pete.
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I guess for a positioner it doesn't matter since (similar to a treadmill) the load doesn't change much whatever the speed) but if you're going to use one on a milling machine or lathe lower speed usually means larger workpiece or tool diameter which means more torque required.
Did you look at that CSR chip I posted? I have a simple wiring diagram which I made for setting maximum and minimum output voltages.
