Direct drive

Specially developed direct drive for Kuhner shakers


The Kuhner direct drive ensures a consistent and reliable shaker performance and is the only drive on the market that allows the shaking diameter to be easily changed by the customer.

With the Direct drive, the speed of the motor is the same as the speed of the containers being shaken. There is no mechanical power transfer by friction wheels, no belt that can break down and no other mechanical wear and tear. The advantages are very low noise levels, minimal power consumption and heat transfer, as well as accurate and reliable speed display.

The stator of the direct drive consists of DC electro magnets and sensors and the rotor is equipped with permanent magnets. The electro magnets of the stator are directly switched by the controller depending on the position of the rotor. As there are no brushes in this system, sparking is not possible.

Quartz precision speed regulation is achieved by microprocessor control and the speed remains constant irrespective of load.

Speed accuracy:          ± 0.1 U/min

Speed indication:            ± 1.0 U/min, digital

Shaking diameter

The shaking diameter is a key factor for the cultivating conditions in a shaken bioreactor. Given the same speed; the bigger the shaking diameter, the better the oxygen transfer rate inside the culture. This applies to microtiter plates as well.


Kuhner offers three standard diameters: 12.5 mm, 25 mm and 50 mm. The user can change the diameter at any time. 


Shakers (the ISF1-X and ISF4-X in particular) can be fitted with additional shaking diameters on request e.g. 9 mm, 19 mm or 70 mm.



Orbital shaking motion

Shaking diameter
12.5 mm 20...500 rpm
25 mm 20...400 rpm
50 mm 20…300 rpm

3 mm 20…800 rpm
(1000 rpm depending on the load)
6 mm 20…800 rpm
9 mm 20…600 rpm
19 mm 20…400 rpm
70 mm 20…250 rpm




If other shaking diameters are needed, Kuhner offers a system that allows infinite adjustment from 0 to 50mm.

The Single Eccentric System

The direct drive uses a single eccentric bearing fitted to the top of the drive so there is no possibility of internal stress between bearings.  The shaking diameter can be changed at any time by altering the position of the eccentric bearing. Three shaking diameters 12.5, 25 and 50 mm are available as standard, with other settings possible on request.




The Parallelogram

The parallelogram ensures identical shaking movement anywhere on the tray, regardless of load distribution. The double steel springs will last a lifetime, unlike bearings and other moving parts.



Aktive brake

To speed up deceleration an active brake is applied to the drive system when the ‘stop’ key is pressed or the door is opened.


Stop at defined position

When using a shaker together with a robotic system the platform must always stop at the same position. Kuhner shakers have 48 stopping points that can be individually adjusted. This system is based on a magnetic lock-in and requires no maintenance.

Calibration of speed

The calibration procedure is automatic and completed in minutes, requiring only a serial interface and a computer with the installed Kuhner Insight software.