KBDA-29(1p) Startup Issue

jbolt

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I was able to get the motor to spool up with the acceleration time set to 10 seconds vs the factory default of 1.5 seconds. Between 20Hz and 50Hz the motor still does the wa-wa-wa sound but no overload LED and then smooths out at 50Hz +. My intent is to run between 30Hz and 90Hz. Based on other motors I have running on VFD's it should run smoother at those frequencies. There are settings in the drive operating parameters I'm not sure about.

S-Curve Time (Accel, Decel), Seconds 0.00 - 30.00, Default =0
Skip Frequency (Hz), 0.00- 240.00, Default =0.00
Skip Frequency Bandwidth (+- Hz), 0.00 - 2.00, Default =0.00
Boost Value (%), 0.0 - 28.0, Default = 7.0
Switching Frequency (KHz), 8,10 or 12, Default = 8
Flux Vector Compensation (%), 0.00 - 10.0, Default = 5.0
 
The adjustment parameters are pretty limited, sometimes you need to do a motor auto-tune so that the VFD loads the motor's operating parameters. This has made a big difference in a couple of recent installs where the motor was coggy until the Auto-Tune was done. There is a description of a static auto-tune on P8 of the manual, but no reference to how this is done. You may try to increase the Boost Value % (3.11) which should increase low end torque. I would try to increase it in 3% increments to maybe 16% and see if there is any improvement. There is also some tuning of the Flux Vector Compensation (3.16). I have also had some motors that did not do well with S curve acceleration and longer acceleration times, but the default S value for the KBDA is 0 which should be linear. You might try 3-5 second acceleration times. Beyond that, you might give a call to KB electronics tech.
 
The adjustment parameters are pretty limited, sometimes you need to do a motor auto-tune so that the VFD loads the motor's operating parameters. This has made a big difference in a couple of recent installs where the motor was coggy until the Auto-Tune was done. There is a description of a static auto-tune on P8 of the manual, but no reference to how this is done. You may try to increase the Boost Value % (3.11) which should increase low end torque. I would try to increase it in 3% increments to maybe 16% and see if there is any improvement. There is also some tuning of the Flux Vector Compensation (3.16). I have also had some motors that did not do well with S curve acceleration and longer acceleration times, but the default S value for the KBDA is 0 which should be linear. You might try 3-5 second acceleration times. Beyond that, you might give a call to KB electronics tech.

Thanks Mark, I'll try a few things.

In the manual they mention a detailed programmable function list as something that can be requested so I will see if I can get that.

Any idea what switching frequency parameter does?
 
Switching frequency parameter 3.15 is the switching frequency in kHz, it will not change the motor operation. Newer motors do fine with 12 kHz, older motors are best kept around 6 kHz or less but this generates more audible noise. Higher frequency tends to heat the coils a bit more and be harder on the winding insulation, but this is not a problem with an inverter rated motor. Could not find any further information on the parameters at the KB site. Sometimes VFDs and motors just do not work well together.
 
I tried some of the parameter changes but not much improvement. The minimum acceleration time is 7 seconds. If I increase the boost over 8 I get a -SC- fault which is a short circuit fault. Lowering the boost below the factory default of 7 does not make a difference. Changing the flux compensation did not seem to do anything. I tried all the switching frequency settings and all that does is make the pulsing on startup quicker. I have a call into KB. We'll see what they say.

As good as I can get it.

 
Looks like the motor and controller are not compatible. I wired the KB controller to the Marathon motor on my lathe and it works as is should. I then wired the motor to the Hitachi drive on my lathe and was able to get it to work. Not sure what the issue is but I suspect the limited adjustibility of the KB drive cannot be tuned for that motor. Now to find another motor.

Sent from my SM-G955U using Tapatalk
 
I don't have that controller, so this may not help... However, I was setting up a new VFD for my Bridgeport last night and ran into a bit of trouble. It wasn't running like it should. After poking around a bit, I realized there is a parameter labeled "Rated motor frequency". The default was 400Hz. No idea why as I've never seen a motor that wanted that high of a frequency. Changing it to 60Hz made it run great at all the speeds I wanted it to run at, about 20-100Hz. My VFD is a Chinesium special, so your nicer unit might not need something this simple.
 
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