Viper 95 Current and Temperature

[cnc_oz]

Hi All,
Just set up 4 Viper 95 drives driven from a smooth stepper and PMDX-122 Break-out board. Software is Mach3. Power supply is 51v
While I am still fine-tuning the servo motors I note that the current at idle for the 4 drives is 1.2A. This is a bit higher than I am accustomed to. Is this acceptable?
The aluminium heatsink back plates get up to 50C. Is this considered safe in the long term, or should I add some additional heatsink fins to the back plates.

BTW the machine is an X-3 Mill which I previously had running with steppers.

Regards
John
Melbourne Australia

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[Larken]

The Viper 95 runs hotter than a viper 200 because it is a single supply drive. The incoming main voltage is regulated down to power the drive logic and the encoder, so there can be a lot of heat dissipation.

How many mA does your encoders draw ?

If you mount them well on the edge to an aluminum chassis or plate thats all you should need for a 50 volt input. When they are run above 60 volts, heatsinking would be necessary. BTW, thats why encoder current on the Gecko320's is limited to 50mA because it works the same way.

I'm using 2 voltage regulator's though, one for the drive logic and one for the encoder, so you should be able to run up to 80mA encoder current. But the power supply voltage plays a part. The higher the PS voltage, the lower max encoder current available. At 90 volts, i wouldn't recommend over 60mA encoders.

Larry

[cnc_oz]

Hi Larry,
I am using CUI inc AMT10x encoders which use 10ma each.
I have added a 100mm square heatsink on each mounting plate.
This has reduced the plate temperature from 50C to 40C which I can live with.
Very happy with the performance so far and am just fine tuning the servos.

John