My experince with this kind of controller, although not this specific brand, is that it's chopping the AC wave (using SCRs) to provide a chopped DC output. It's very much light a light dimmer, but rectified.
It's a simple and inexpensive way to provide a fixed speed control for something like a conveyor belt, but I'm not sure it would work very well for CNC. I think that the torque curves are different than with straight variable DC as well-less low speed torque. Your assesment is probably correct-that using a PM motor with PWM drive is the best way to go. Javid ----- Original Message ----- From: "Kirk Wallace" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Saturday, December 29, 2007 11:09 AM Subject: [Emc-users] KBIC Controller >I am trying to understand how the KBIC controller works. > > http://www.galco.com/scripts/cgiip.exe/wa/wcat/webpromo2.htm?promo=120KBIC > > My understanding so far is: > > Universal motors are brush motors with windings for the armature and the > stator. They can run on DC, or more commonly, AC if both windings are > kept in phase. To reverse direction, the polarity of the armature or the > stator is reversed. The speed of the motor can be controlled by changing > the average voltage to either the rotor or stator by PWM, PDM or SCR (I > don't know the term, but like a light dimmer). > > Because there is mains voltage on the control potentiometer, the KBIC > appears to use an SCR to control the passing of mains current to the > motor. There seems to be no provision for motor direction control, but > an external means of reversing the polarity of a winding might do it. > The documentation mentions that the controller has current limiting to > prevent demagnetizing permanent magnet motors, but provides no > information on how to use the controller with PM motors. Usually, > Universal motors are used where cost is a major factor, but when you try > to control one, the controller, and if needed for CNC, the analog input > and reversing options are fairly expensive. For CNC, it seems that you > would save money by changing out the motor for a PM motor and PWM > controller. > > Although, if you run the Universal on DC, it should act like and be > controllable by a PM motor controller? > > Am I off base on any of this? > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
