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Author Topic: Replacing a Resolver of an AC Servo with an Encoder  (Read 13509 times)

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Offline Dan13

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Re: Replacing a Resolver of an AC Servo with an Encoder
« Reply #20 on: August 28, 2009, 01:15:41 PM »
Nosmo,

Thanks for clearing things up. Now it makes sense to me :)

Daniel

Offline Hood

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Re: Replacing a Resolver of an AC Servo with an Encoder
« Reply #21 on: August 28, 2009, 01:36:48 PM »
Well not quite, the drive AND the feedback device. IOW an AC motor with resolver will not run on a  BLDC drive without changing the motor resolver to equivalent hall effect device.
The Fanuc AC Red cap motors I mentioned earlier have a differential encoder and a 4 bit binary code which they use in their systems to produce a pseudo sinusoidal pattern from the 4 bit code, similar to what a resolver would produce.
Jon Elson is selling a unit where he  has found a way to convert this code for BLDC commutation.
I have generally changed the whole encoder if I get the right price.
Nosmo.

Ok so think I have it now, the motors I use have encoders with hall signals so they can be classed as either AC or BLDC servos depending on the drive I use. My drives use the hall for startup commutation so will be AC but if the drive used the Hall continuously then they would be classed as BLDC.
 I also have a motor that I put an encoder on that only has A B and I channels so it can be used on my drives if I enable Auto Sensing for startup commutation, this would be classed as purely an AC Servo as BLDC drives wouldnt be able to run it.

Hood
Re: Replacing a Resolver of an AC Servo with an Encoder
« Reply #22 on: August 28, 2009, 04:11:55 PM »
this would be classed as purely an AC Servo as BLDC drives wouldnt be able to run it.

Hood

This would pretty much sum it up, there are none that I know of anyway.
Nosmo.