ACS 800 drive output voltage increasing when the nominal frequency is reduced
I have a question. Actually I am using a ACS800-01-0060-5 drive with incoming voltage of 400V. The output of the drive is connected to multi motors and connected in delta connection. The drive is in scalar mode (99.04) and drive nominal voltage (99.05) is set at 250V and the nominal Frequency (99.07) is set at 50HZ. Now my issue is the Drive output voltage i am receiving is 185V due to which my motor rpm is also slow. So i tried to increase the frequency to 55Hz and strangely my output drive voltage reduced to 165V, so i tried to reduce ny frequency(99.07) to 43HZ i got 230V and the motor rpm got increased also the power consumption too increased. Can anyone explain why is this behaviour of the drive.
Note: The drive is in profibus communication with ABB Plc.
Voted best answer
Check if nominal current is set correctly for Delta motor configuration, crosscheck nominal current at motor nameplate for Delta connection. In case of parallel motors connection you should calculate sum of all Delta nominal currents.
Other possibility is the drive is generating power and returns power to DC circuit, thats why DC is increasing. As example may be conveyor or lift moving down while gravity generates energy. What kind of drive application is it?
In addition to the other answers, there are few important things, that I found in your questions:
- scalar mode of ACS800, delta connection of the motors and fieldbus control of the inverter.
What is the nominal voltage of the motors at delta connection?
Look here for similar case - may be the same idea is used in your case, which explains the output voltage 230VAC at 50 Hz:
Here is another article, which could help you, when you have fieldbus control: