Questions for KB ac drive users

P

PT Doc

Joined
Dec 24, 2011
Messages
1,298
Hi guys. I was hoping those that use the KBAC series of ac drives for their variable speed grinder setups could answer a few questions.

Are you running the drive with constant torque or adjustable torque (jumper #10)?

Is the drive in fixed boost or adjustable boost (jumper #6) If in adjustable boost, how is the trim pot set on the boost dial (4th trim pot from the left)?

I ask since using the KB factory settings on my KBAC 29 (1P) KB model #10001, my 3hp Baldor motor would shudder when the potentiometer dial was between 22 and 50 on the dial. When set the way Rob Frink recommends for the KMG, the motor would vibrate between 18 and 50 on the dial. All of this is without any load since the KMG is not yet hooked up. After talking with KB Electronics, then asked me to try variable torque. This stopped the vibration. When I asked what that adjustment did and why it stopped vibrating, I didn't get a good answer. I also emailed Rob and he had no idea on the settings. Baldor was not helpful even after looking at the KB ac drive manual.

This KB ac drive is 240 single phase in only and 240 3 phase out and is rated for 3 hp motors. My Baldor motor is EM3611T which is 3phase 1760 rpm 8.4a and is inverter rated with a 20:1 turndown, so this motor should go down to 100 rpm without a problem. The drive and motor are well matched based on capabilities, output and ratings.

Thanks in advance for the help.
 
When I first bench tested my controller and first motor, I had some shuddering and shaking.

Once I put a wheel on the motor it disappeared and I stopped worrying about it.
 
That is what I was hoping also. I just received the KMG but no pulleys or grinding belts yet but should have it all running by end of next week. Thanks for the insight. What type of motor were you running when you had the shuddering?
 
1.5 hp 3 phase on the kbac27d 2 HP controller

So you will have some differences to your 3 HP motor and controller
 
I locked the old thread, since rashid isn't here any more. Post questions in this thread.
 
I have a baldor 2hp 3ph and had the exact same issue while bench testing. I installed the drive wheel on the shaft and most of the problem went away. Then I assembled the whole thing and it pretty much went away. Add a belt under some spring tension and the issue is gone (for me anyway). It seems the motor/vfd likes to have some load. I can not stall my motor if I try.
 
I had a problem with my 27d that manifested on good motors, after I tested a bad motor with it. It mist have caused an alarm or something, which dynamically adjusted the base settings, since none of the motors I had previously used would operate without wanting tto vibrate themselves apart.

I fixed it by adjusting the CL pot and Comp pot. I can't recall which but I turned one all the way down, and one all the way up. If you need me to check which was which I can.
 
If you are up for popping the ac drive open, I would greatly appreciate it. are you on constant torque and fixed boost,mjumpers 10 and 6? Any changes on the boost trim pot. A photo or 2 would work also. Thanks a lot.
 
Yeah np, I get a pic in a bit. Its running a disc grinder now and its pretty convenient to get at.
 
You must log in or register to reply here.
Back
Top