does anyone have experience with the P76 drive and an induction machine designed for 87Hz operation (delta/star - 230/400V)? Specifically, I’m looking for advice on autotuning for this type of drive.
The machine is designed for 87Hz operation with a nominal winding voltage of 400V and is connected in delta. Regardless of whether I use the values 230V/50Hz or the extended values 400V/87Hz (with corresponding current), autotuning results in “ripple motion” or “no motion.”
The only way I can get the drive to operate correctly is to set the nominal frequency to 87Hz, perform autotuning, and then change it to 230V/50Hz. The inverter recalculates resistance and inductance, allowing the drive to run smoothly.
However, this method is quite impractical. I’d like to find a more straightforward way to configure the system and simplify the autotuning process.
Any suggestions or insights would be greatly appreciated!
Regards
Michal Malek
It seems that this issue has already been resolved (or canceled)
Well, it is important to use the correct motor parameters and see how the motor is actually wired.
Most motors are built for star-wiring, but many can then also be used in delta-wiring. However, the inverter then ‘sees’ a motor with significantly different parameters (resistances, inductances, power).
You can take a look at how the parameters change here, for example:
There is also a risk of overloading in Delta wiring. Theoretically, you can demand 1.7x the power from the motor. The thermal limit then sets the practical limit.
After inserting the correct motor parameters there should be no difference between star and delta regarding the real autotuning. If there is still some unexpected behaviour or noise you should contact your local office.
The P76 in the 400V version has its nominal point set to 230V/50Hz.
The motor is connected in delta (as I mentioned, the motor is designed for 400V, even though this is not indicated on the nameplate)
I thought it could be solved by changing the connection to star, performing autotuning, and then switching back to delta, but this is much more complicated than the solution mentioned above.
OK, we can start with this setting, even though the nominal voltage and frequency could also be 400V and 87Hz.
However, when useing your settings and motor are connected in delta and you perform autotuning, the motor exhibits unsteady behavior. You must perform autotuning with different nominal values (the best approach is to set them directly on the inverter) and then revert to 230V/50Hz. This process is inconvenient, especially for service technicians. I am looking for a solution to overcome this issue.
I agree with you. 400V/87Hz are suitable, too. But then the question is what you insert for the power: a) the 1.7x by theory or b) the thermal limitation from manufacturer. So I prefer to insert the winding data from manufacturer from type plate
However, when useing your settings and motor are connected in delta and you perform autotuning, the motor exhibits unsteady behavior
so the conclusion is: even when you use the ‘correct’ data from type plate the results from autotuning are not fine instead you have to use 400V/87 Hz as a workaround ?
Then it would be nice to share the results with your local B&R office,
e.g. what were the results of the tuning processes with both variants:
The result is that while there is a way to tune it, it is inconvenient from a practical standpoint. I believe there is a similar issue with the P3 feeding an induction machine, where autotuning must be performed in a star connection even though the drive operates in a delta connection.
In both cases, I am unable to find a simple solution.
No, I think it is the same topic because the principle is the same.
Yes, I can read the parameters, and I do so (via SDO). Perhaps there is a way: I could perform autotuning, recalculate the parameters in the same way the inverter does, and then write them back to the inverter. However, it would be better to gain a deeper understanding of the principle.
Perhaps there is a way: I could perform autotuning, recalculate the parameters in the same way the inverter does, and then write them back to the inverter
you can just read out the parameters via SDO and then switch the hardware configuration of the Acoposinverter to ‘User defined’ (as I did above) and then transfer the project
However, it would be better to gain a deeper understanding of the principle.
the principle is ‘simply’ to measure resistors and inductances of the path (motor + cable) and calculate the four mentioned parameters. Afterwards the current controller is feed with this parameters.
If the parameters are already known, you can also enter them manually in the configuration by yourself.
