Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: rrc1962 on December 14, 2010, 09:02:50 PM

Title: Servo Motors 101
Post by: rrc1962 on December 14, 2010, 09:02:50 PM

This may be a stupid question, but is a servo motor just a DC motor?  If I take a 60VDC servo motor and apply 60V to the terminals will it spin at it's rated RPM?  If I reverse the terminals, will it reverse direction?  I need a NEMA 23 DC motor.  All I need to do is control on/off and forward/reverse which I can do with DPDT relays.  It would also preferably have a brake, which should be able to be added to the tail shaft of the motor.

Thanks

Title: Re: Servo Motors 101
Post by: Hood on December 15, 2010, 03:17:17 AM

There are several flavours of servo motor, brushed DC, Brushless DC and AC, the latter two are in my understanding one and the same as it is the driving method that determines whether they are classed as brushless or AC.

From the sounds of it you just require a DC motor and not a servo, a brushed DC servo is basically just a DC motor with some other stuff attached (encoder, tacho etc) but they work exactly as you describe so if not requiring position control you can ignore the encoders etc and just apply the voltage and polarity required.
Hood

Title: Re: Servo Motors 101
Post by: rrc1962 on December 15, 2010, 08:45:39 AM

Thanks Hood.  I was looking at servos just for the Nema 23 standard mounting, but you're right, any DC motor would work.