[dougstuiv]

I have an '82 Shizouka CNC mill with servo drives. They're big NEMA 42 size motors, and I'd like to replace the drive electronics but keep the motors if possible. Will Viper Servo drives connect to them? Are there new encoders available for monitoring position that I would install? I'm uncomfortable buying everything from various vendors and then hoping it will all work together. The mill's old power supply seems to work, but the computer is dead.
Doug

[routerman]

What voltage and current are the motors rated for ?

[dougstuiv]

I don't know.
It has an Allen Bradley Bandit IV controller with Glentek drivers and motors. The tags say "Glentek Permanent Magnet DC Servo Motors"
max 2000 rpm
565 torque in. oz.
11 amp
6 ohms
BEMF-?/1000 rpm: 38

[H.O]

Hi Doug,
I can't vouch for the Viper but I'm seriously concidering trying them out. Just going by the specs on your motor (and the Viper) they should work fine together as long as you fit encoders to the motors.

You state 6ohms? Are you sure it doesn't say 0.6ohm? If so:

The max current is 11A and the armature resistance is 0.6ohm. That will produce a voltage drop in the armature of 11*0,6=6.6V Then the voltage constant of the motor is 38V/1000rpm and the max speed is 2000rpm so 2*38+6.6=82.6V. Then there's some voltage drop in the Viper so a powersupply of ~90VDC will probably be a good fit.

EDIT: About the encoders, just about any encoder will work as long as it is incremental and designed to operate on 5VDC. Make sure to get one with differential outputs since that's a lot better when it comes to noice issues. Not all servo drives has provisions for differential encoders but the Viper does so that's good. USDigital's E5D would probably be a good match.

Hope it helps!

/Henrik.