How can I find the Time Constant of older braking resistors for use with the ATV900 series drives?

Issue:
I have an older braking resistor I want to use with my ATV900 series drive.  How do I find the time constant?

Product Line:
ATV900 series drives.

Environment:
All models, All serial numbers where a braking resistor is being added.

Cause:
The ATV900 series drives requires a "time constant" setting when using a braking resistor.  This information is not available for older resistors.

Resolution:
It is recommended to use the braking resistors in the ATV900 catalog which have this value listed.  Resistors from older applications may not be compatible with the braking resistor/transistor system of the 900 series drive.  This information will not be available on some older resistors.