Superior Electric Steppers

[m_c]

Without finding the datasheet for the original motors, 200 oz-in = 1.4Nm.
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The HSS57 closed loop servo will work well. Just remember you'll also need to get new couplers/pulleys, as I'd guess the shaft on the original stepper shaft will be a good bit bigger than a modern Nema 23 motor.
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Personally, I'd avoid the integrated stepper, not because it won't work, but because you need to run the step/dir wires to the motor. If you've not got differential (line driven) step/dir signals available, it makes things very prone to noise.

[Agathon]

Thanks again. Yes, perhaps I'll avoid the integrated solution - a pain if the driver packs up too.

The nominal torque of the original motors is 300 oz in which is 2.1Nm - the machine's manual states the "maximum holding moment" as 3.2Nm.

I found this data sheet on line - https://drive.google.com/file/d/0Bxr...ew?usp=sharing

Thanks for the Leadshine observation. The Nema34 Leadshine motors are only two phase.

[Agathon]

Just realised that it was your Youtube video of a Leadshine closed loop stepper that turned me on to the idea.

Maybe, as you've said in other threads, I'd be better off with conventional Nema34 steppers and digital drivers. Just like the idea of the smooth closed loop, but there's no point if the two phase motors aren't any smoother.

Thanks again for your help.

[JAZZCNC]

Just realised that it was your Youtube video of a Leadshine closed loop stepper that turned me on to the idea.

Maybe, as you've said in other threads, I'd be better off with conventional Nema34 steppers and digital drivers. Just like the idea of the smooth closed loop, but there's no point if the two phase motors aren't any smoother.

Thanks again for your help.

Yes that's me.!!

Standard 34's with Am882 will be perfect for Mill. When correctly setup there will be no difference between 2 phase Closed loop in performance terms.
If the machines loses position the closed loop will bring it back into line yes.!! . . But the damage will still have been done if it was machining at time. Again Correctly sized and setup stepper shouldn't lose position so it's not problem. I've built loads of routers using the AM882 and Em806 drives along with 34 and 23 steppers which travel high feeds where torque is lower and they don't lose position so on slower moving mill you won't have any trouble.

[Agathon]

It's a shame that the Leadshine Am882 doesn't appear to be available in the UK. Is there another driver worth considering?

Just a final thought on the closed loop steppers. Given the details of the original motors, do you think the Leadshine 3ph Nema23 2Nm motors would provide enough torque?

[JAZZCNC]

Just a final thought on the closed loop steppers. Given the details of the original motors, do you think the Leadshine 3ph Nema23 2Nm motors would provide enough torque?

Difficult to answer without seeing machine etc but the fact the old where 34's and probably wired in series which gives more torque lower down Rpm then it will be close call and one I wouldn't take personaly.

AM882 and 34's would be safer bet.

[Agathon]

Ouch, those EM806 drivers are pricey - by the time I've bought a motor, I've exceeded the price of the Nema34 closed-loop units from Rattm motor in Germany (http://r.ebay.com/jCcjOw).

I notice these drivers claim to be digital - http://r.ebay.com/chJSF8

[m_c]

It's a shame that the Leadshine Am882 doesn't appear to be available in the UK. Is there another driver worth considering?

Just a final thought on the closed loop steppers. Given the details of the original motors, do you think the Leadshine 3ph Nema23 2Nm motors would provide enough torque?

The AM series has been replaced by the EM series. The new AM882 equivalent is an EM806.
The original HS closed loop stepper system has also been replaced with the Easy Servo range.

[JAZZCNC]

Thanks for the Leadshine observation. The Nema34 Leadshine motors are only two phase.

Yes the 34's are but the smaller 2nm leadshine hs57 are 3 phase. Personally I wouldn't pay the extra for 2 phase closed loop over standard stepper with Digital drives.