Hanna® Instruments Magnetic Stirrer

Often in the lab, a sample is removed from a stirrer before the speed is adequately reduced. Normally this would cause the internal motor to accelerate until it is damaged. To control the speed from changes in viscosity or removing of the load the HI190M-1 magnetic stirrer incorporates the Speedsafe™ mechanism. With Speedsafe™, a speed sensing device (opto-sensor) is coupled with an FVC (frequency voltage converter) to monitor the stirring speed. As the speed reaches a preset maximum level, the speed limiter shuts down the VCO (voltage-controlled oscillator) to slow down the motor speed. This ensures that when the load is suddenly removed from the stirrer, the motor will not accelerate to such a high speed that will be hazardous to both the user and the stirrer; a feature not commonly found in conventional stirrers.