Treadmill/Variac controller

[cross thread]

I'm intrigued by this set-up , recently I scored a Pratt & Whitney 3c mill . This Variac set-up , I think would work well . The P&W mill was still hooked up to the Speedranger (a motor and variable speed trans) . It gave me pause but I couldn't take the Speedranger because first it runs on 440v . There is a guy (on Youtube) that got one to run with a VFD . But even so I don't have the room for that beast or the means to handle it , so it stays with the owner . Anybody out there need a Speedranger ? The Speedranger explained http://www.lathes.co.uk/prattwhitneymiller/page4.html
My real question , anyone out there running a treadmill motor on a Variac ? A good video on Variacs

 

[lordbeezer]

Very interesting since I have a variac I picked up awhile back and several motors off commercial treadmills.

 

[Nutfarmer]

I would keep the speed ranger , just because that was original to the mill. Nice mill. Most 440 volt three phase motors can also be wired to run on 220

 

[benmychree]

Variac puts out AC current, treadmill motors want DC.

 

[Ulma Doctor]

KB125 dc drives are relatively cheap and can handle 1.5hp dc motors on 110vac and
3hp dc motors on 220vac

MC40 and MC60 controllers are also suitable to drive the dc motors with 110vac or 220vac input

 

[RJSakowski]

I initially tried a Variac plus diode bridge and filter capacitor on a treadmill motor. It has lousy low speed torque characteristics. My shop-built PWM controller has excellent torque as low as 1% of full range motor speed. (The torque exceeds the capability of the belts to deliver it to the spindle.)

 

[cross thread]

Very interesting since I have a variac I picked up awhile back and several motors off commercial treadmills.

Have you got any of them up and running ?

 

[markba633csi]

RJ is correct, variac controls have poor speed regulation. You want a control with feedback like KB or Dart

 

[cross thread]

RJ what you have done sounds like what I need . A shop built PWM , how did you do it ?

 

[cross thread]

I would keep the speed ranger , just because that was original to the mill. Nice mill. Most 440 volt three phase motors can also be wired to run on 220

Well like I said , it gave me pause . It reminds me of the Spectrum commercial , you want to hold the Speedranger ? Well you can't because it will rip your arms right of your body .