Kest Tech­nology produces aseptic mixers for the biotech­nology and phar­ma­ceu­tical indus­tries and is very familiar with phar­ma­ceu­tical manu­fac­turing require­ments. “Our mixers are used to manu­fac­ture highly sensi­tive medi­cines, some of which are worth several billion dollars,” explains Anders Elliot, Marketing Manager at Kest Tech­nology. That is why the company wanted high-perfor­mance elec­tric motors for its new gener­a­tion of mixers, making it possible to operate even compact models reli­ably and effi­ciently. The synchro­nous AC motors that were previ­ously used could no longer meet these require­ments and were there­fore replaced with compact, elec­tron­i­cally commu­tated and brush­less motors from ebm-papst. 

Precise control ‒ up to 80 percent less energy

As the mixers are often in oper­a­tion around the clock, it was espe­cially impor­tant to find an energy-effi­cient solu­tion. The motors offer a high degree of effi­ciency across a wide speed and torque range. “We have been working with ebm-papst for about ten years,” says Elliot. “When we were looking for drives, many suppliers were unable to satisfy our energy effi­ciency require­ments for the motors. That is why, in 2017, the product from ebm-papst was chosen for this project.” Jörgen Blomqvist is OEM Busi­ness Devel­oper at ebm-papst in Sweden and works with Kest Tech­nology on the project. He explains: “The previous AC motor was much larger and used a lot more energy. By compar­ison, the smaller EC motors use as much as 80 percent less energy and deliver effi­ciency of up to 90 percent.”

Three different sizes of motor from ebm-papst are used in the mixers. The large mixer is equipped with an ECI 80 internal rotor motor and K1 elec­tronics module, combined with an external K4 controller. VDC 49.15 external rotor motors with inte­grated K4 elec­tronics are used in the medium and small mixers, making them easy to control digi­tally. “The motors from ebm-papst are inher­ently smart,” says Blomqvist.

Their speed is now easy to control thanks to inte­grated elec­tronics and sensors. As EC motors are oper­ated with direct current, the rota­tional speed can be varied by applying an external signal voltage. There is no longer any need for an external vari­able frequency drive, as is required for AC motors. This not only saves space but greatly facil­i­tates actu­a­tion. Depending on the medi­cine being manu­fac­tured, oper­a­tors can adjust the speed flex­ibly and also benefit from the many other options offered by the ebm-papst K4 controller. “This control preci­sion is very impor­tant for our customers,” says Elliot. 

(Image | Kest Tech­nology)

Brush­less magnetic drive

In the AC motors that were previ­ously used, the magnetic field was reversed using mechan­ical brushes. These generate fric­tion when they rotate, resulting in substan­tial energy loss in the form of heat. In EC motors, the polarity is reversed by an elec­tronic controller that does not produce any fric­tional heat. This means that no addi­tional fan is needed to cool the mixers. “The fanless drive unit is ideal for the phar­ma­ceu­tical industry in partic­ular because there are no fans to disturb the clean envi­ron­ment and sensi­tive air flow,” says Elliot. The EC motors are also much quieter than their prede­ces­sors. In clean room work­sta­tions in partic­ular, opti­mizing the noise prop­er­ties of equip­ment is impor­tant to enable employees working close by to concen­trate to the full. Thanks to their Noise­less­Plus gears, the VDC motors are partic­u­larly quiet.

Compact design

The ebm-papst EC motors are far more compact than the AC motors that were previ­ously used. However, the smaller space made designing the elec­tronics a chal­lenge. “We have a sepa­rate control unit, which is not ideal. One cable is for the signal and one for the power” explains Elliot. “Because of labo­ra­tory clean­li­ness require­ments, we wanted just one cable between the motor and the control unit.” Working closely with the ebm-papst team in Sweden and Germany, Kest Tech­nology found the solu­tion to this tech­nical chal­lenge. “We had fantastic support from our partner at ebm-papst,” says Elliot. “His tech­nical exper­tise is very impor­tant because he under­stands just what we need.” The ECI motors ensure the safe and reli­able oper­a­tion of the mixers and satisfy the strin­gent EMC require­ments for elec­trical appli­ances in medical appli­ca­tions.