ACS880 SUDDEN SPEED DECREASE
Greetings sir,
I have a ACS880 VFD for sugar cane milling application. The VFD receives a 4...20 mA speed reference from a AC 800F Controller via a series 500 Slave panel. We set the speed reference from Freelance DCS.
Sometimes the VFD decreases the speed output of the VFDin a very sudden way the speed with no apparent reason. We checked the fault log in the VFD but we do not find any cause.
What is the cause of this issue? Can we solve it modifying any parameter?
Thank you in advance for your response.
Asked 6 months ago
Answers
1
Hi Juan
based on the description of the problem you did, it is not easy to identify the cause.
Meanwhile, to give more transparency to your configuration, please always indicate the type and model / size of the drive you are writing.
Some possible checks you can do:
Check if during the lowering of speed on the drive, you have a corresponding increase in output current. If the current increase is very large, the decrease in output speed could be a desired reaction of your drive, to limit overloads. In this case, perhaps you can act on the gain of the system, but without data I do not risk giving you other suggestions
Check if the reference output from your DCS remains constant or if it changes during the speed decreases
Without other information it is really not possible to make any other hypothesis
Hope this help you
based on the description of the problem you did, it is not easy to identify the cause.
Meanwhile, to give more transparency to your configuration, please always indicate the type and model / size of the drive you are writing.
Some possible checks you can do:
Check if during the lowering of speed on the drive, you have a corresponding increase in output current. If the current increase is very large, the decrease in output speed could be a desired reaction of your drive, to limit overloads. In this case, perhaps you can act on the gain of the system, but without data I do not risk giving you other suggestions
Check if the reference output from your DCS remains constant or if it changes during the speed decreases
Without other information it is really not possible to make any other hypothesis
Hope this help you
by kstoilov
Hi,
Without more detailed information, I would give you the same advises like Mr. Flavio's below:
- check the inverter's current during sudden drop of the speed - it could reach the current limit (or torque limit)
- check if the current setpoint from your DCS is stable = the real signal (may be create a trend of it?)
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