What is an Overspeed Alarm?

[travis]

What is an Overspeed Alarm as pertaining to a motion control system? I'm looking for tips on real world troubleshooting of overspeed alarms or faults. Thank You!

[stantheman]

Re: What is an Overspeed Alarm?

Overspeed alarams can be caused by a few different things.

• bad wiring: check your cabling leading to the resolver/encoder on your motor system. This includes possible loose pins and bad connections at the termination points.
• bad shielding: Your cables should be shielded internally and properly grounded at one end only; which should be at the drive or control cabinet. Motor systems with a resolver are sensitive to noise and the overspeed alarm can result from common noise.
• bad resolver alignment: If the resolver coupling has come loose for any reason or if your resolver has changed position in relation to the servo motor it will throw out an overspeed alarm.
• resolver wiring: If you have replaced any components in your servo motor system including the resolver, motor, drive, or cabling, it could be connected wrong. The resolver wires can be wired in reverse which could change the location of the zero position. Mis-wiring can definitely cause overspeed alarms also.

These are just some suggestions, but they should encompass most of the reasons behind overspeed alarms.

[2106tech]

Overspeed alarms aren't uncommon. I have had this pop up when I have bad resolver wiring. My experience hasn't always been a bad resolver, more often I've had bad resolver wiring.