dc drive with resolvers

[don_harby]

I am looking for some drives for dc brush motors with resolvers. The motors are around 100v 15A. Any idea where to look? Are there any low cost or used ones out there?

[Karl_T]

I just sold the drives out of my Hardinge CHNC X and Z axis servos this size. See this on ebay fairly often. Resolver is really old technology, look for tweny year old equipment.

Why don't you want to trash the resolver, install a cheap encoder, (US Digital) and install a modern drive?

Karl

[Al_The_Man]

Also, modern DC drives do not need any feedback, even tach's are obsolete, The feedback goes direct to the control.
As Karl mentioned, Resolvers for position feedback are pretty much obsolete for DC motors, AC sinusoidal drives still use them.
You can get converters, but the cost is about equal to encoders, Renco is another good source.
Al.

[bunalmis]

Why don't you want to trash the resolver, install a cheap encoder, (US Digital) and install a modern drive?

Decoders of Incremental shaft encoders very sensitive to noise. But resolvers work in the noisy environments.

Last modern controller accept resolvers and inductasyn.

[don_harby]

I don't want to change them because they are pretty large motors. The way they are made it would be pretty hard to change resolvers to encoders. They are kindof built into the motors. Also I have a few brand new motors that came with the machine as spares. Thought I might be able to find some drives.

[Al_The_Man]

I have changed over a few kinds of motors to encoder and always found the resolvers accessible for service/replacement, so it normally does not involve that much to change over, you will probably find that the resolver is geared up in side the motor as resolvers without this offer low resolution.
The means that there is usually a rear shaft on the motor and a through-shaft encoder type can be fitted in place of the gear drive.
The gear drive should be discarded.
Al.