Newbie- Servo & slow speed

[Kencor1]

I Have built a home cnc router with stepper motors, I now want to build one using DC servo motors, the ones that I am looking at are the NEMA 34
dc servos from kelinginc.net. My question is, does anyone know if I can use these buy just hooking them up to my lead screws direct (like my stepper motors) or will I need some type of Gearing to have smooth operation at slow speeds?

Thanks,
Tom

[johnmac]

Can anyone help? I have been wandering the same thing.

John

[Al_The_Man]

NEMA size rating does not indicate torque, just mounting frame size, if you use the correct size motor for the application, servo's are quite capable at low rpm's.
Like steppers, servo's have maximum torque at zero rpm.
I generally use 1000cpr encoder, which x4 using a .2 lead BS, gives 20,000 counts/inch.
I can position to within one count error.
Servo's are capable of being geared high, this allows an economical sizing of the motor due to the high rpm capability of a servo and still maintain torque up to the max. rated rpm.
Al.

[johnmac]

Thanks, Al. So, if I understand correctly, If I'm happy with the power of my steppers, I can replace them with servos of the same torque rating. Then I will get the same low speed torque with higher rapid speeds?

John

[Al_The_Man]

Yes, essentially you should.
Al.