torquecurves for keling motors?

[gotis]

I´m looking for torquecurves of the 640 and 1200oz/inch motors, anyone got them?

[vacpress]

did you ask the kelling people? ive called them before, they are local to me. the gentleman i spoke with was asian and not extremely easy to communicate with. he agreed his motors were perfct for gecko drives, and also attempted to sell me his imported drives... people seem to be sceptical of the quality of these motors, maybe. it would be cool if someone with more info let us know. i am considering these motors..

[H500]

I would be interested in hearing from people who used them also. They have a good selection of 8 wire motors and the price is very competitive. My biggest reservation about them is the communication. They did not answer my first email completely and then failed to respond to a follow up question.

[dertsap]

i looked at there motors they are all 4 phase wouldn t the need a fairly heavy power supply to run ?

[vacpress]

these big motors are probably best for large power supplies and drivers, yes... i would imagine.. 4-6amps * 3 or 4 axis... thats alot of power...

[dertsap]

i was thinking if say at 4 amp/phase you would need 16 amp to run a 4 phase motor right ?

[jeffs555]

i was thinking if say at 4 amp/phase you would need 16 amp to run a 4 phase motor right ?

No, you would need less than 4 amps per motor. Generally, with a chopper drive and a supply voltage much higher than the motor voltage, the supply current will be less than 2/3 of the rated phase current.

Basically, the difference between two and four phase is how you drive it, not the motor itself. Unipolar is considered 4 phase and bipolar is considered 2 phase, so an 8 wire motor can be driven either 2 or 4 phase.

[gotis]

Got a Z-axis with 250mm stroke, 20mm ballscrew 5tpi with 2 Star rails and 4 blocks size 20 and a weight of around 60lbs,hoping to mill aluminum. what size stepper should I go for?

[dertsap]

personaly i m not sure motor size for that weight some of the other guys would be good at that , but i just wondered if you have a counter balance weight or something to that effect , then you may get away with a lighter motor ,

[ViperTX]

Guys.....some links....so we can look for ourselves....

[jeffs555]

With a 5tpi ballscrew, it only takes 0.56 oz-in of torque to raise 1 pound, or only 35 oz-in to raise 60 lbs. Since torque drops off with speed, and it also takes torque to accelerate the motor and the screw, you would want a lot more than that. Just guessing that something around 150 oz-in or more would work.

[gotis]

With a 5tpi ballscrew, it only takes 0.56 oz-in of torque to raise 1 pound, or only 35 oz-in to raise 60 lbs. Since torque drops off with speed, and it also takes torque to accelerate the motor and the screw, you would want a lot more than that. Just guessing that something around 150 oz-in or more would work.

THANKS! for the math, that helps me alot, I`ve been looking at the 640oz motors from keling and this sets my mind to rest that they will be up to the task.

If I´m not mistaken the tormach use around 640oz steppers as well?