Zero Torque Feature - Caframo BDC1850 Handbuch

• Power LED is on when stirrer is on.
• Pause LED is on when stirrer is paused and set speed is displayed.
• Display Button - The LEDs indicate which parameter is displayed. When
paused, the display will always show set speed. The rpm LED will be flashing
indicating this is a set speed.
Overload conditions will occur when:
• The torque demand is outside the stirrer's capabilities (solution is too viscous).
Overload LED will illuminate. Reduce torque requirements of the application to
continue mixing.
• The stirrer overheats due to extended operation at very high torque and/or speed
demands. The stirrer completely shuts down and must cool before operation can
resume.

Zero Torque Feature

Theory
In mixing applications the magnitude of torque depends on three parameters: First,
the speed in revolutions per minute; second, the diameter of the propeller; and
third, the viscosity of the material being mixed. Additionally, a small amount of
torque is required to move the mixing impeller. In small bench top applications
this additional or overhead torque is negligible and is generally independent of the
force required to mix material.
Zero Torque Feature
The zero torque feature allows the operator to null out the additional overhead
torque of the stirring apparatus similar to a tare feature on a scale. The feature can
also be used during the mixing process and allows the operator to see change in
torque caused by the change in material viscosity.
Run the stirrer at low speed for a half hour before zeroing torque. As the motor
warms up the torque can change slightly. Setting the torque when the stirrer is
warm will increase the accuracy.
A negative number indicates a reduction in viscosity and a positive number incates
an increase in viscosity.
Other button functionality
• I f the stirrer is powered off when in zero torque mode (Ncm LED flashing), the
stirrer will be in this mode when powered back on. If the stirrer is unplugged or
power is interrupted, the stirrer is reset and the feature will not be active.
• The speed can be changed any time - while the stirrer is running or in pause.
When the speed is changed, the speed in rpm is displayed while the speed is
adjusted. If torque was displayed prior to the change in speed, the display will
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