One rheometer, two motors

The MCR 702 rheometer with modular TwinDrive technology developed by Anton Paar covers all possible rheological applications with accuracy of 1 nNm and features such as the IsoLign Piezo flange for measurement gap control down to 10 nm. TwinDrive technology combines two synchronous EC (Electrically Commutated) motor units in a modular setup: the upper EC motor is permanent, while the lower motor can be extracted and integrated at will.
In the 2ED mode, the MCR 702 uses both motors as drive units and as torque transducers. The motors can easily be set to rotate in parallel or in opposite directions. This dual motor configuration opens up entirely new possibilities in rheological analysis. One option is the counter-rotating mode for enhanced microscopy. The device can operate at maximum shear rate for the combined motor pair and be used for extensional rheology applications and for parallel rotation tests at different speeds. This mode uses the motors in a more synchronized fashion, creating "different demands" on each of them. Furthermore, one motor may be stopped and used solely as a torque transducer while the other performs the drive function, transforming the device into a separate motor transducer rheometer for rotational and oscillatory tests.
In the EC mode, the lower motor may be removed so that the unit can be used as a single drive rheometer, getting the most out of the TruStrain™ capability of the motor for "classic" stress-controlled tests.
MCR 702 TwinDrive offers ground-breaking nano-scale precision in such applications as low-torque measurements down to a minimum of 1 nMm, and the control of angular deflections down to 100 nrad. This precision also extends to the system's measuring gap control: the new IsoLign Piezo flange can change gap size by as little as 10 nm.