In this case, the simplified motor power equation = Voltage (V) x Current (I). When the load on the pump decreases by slowing it down with a Flux Drive ASD, the motor continues to run at its constant speed (i.e., 1200, 1800 rpm) but the motor current (I) reduces, thereby reducing the load / power on the motor. Another good analogy is to look at riding a bike on a flat level grade. When keeping the pedal speed constant (no shifting) and starting to go up a hill, it takes much more energy (power) than going downhill. The person in this case is acting like a constant speed motor and consuming more or less power while operating at constant speed.
Operation of all AC induction motors at reduced power will decrease the power factor of the local system. This is a result of operation at reduced speed / power and not directly caused by the Flux Drive ASD. In rare occasions, Utility providers may charge a penalty if the facility’s power factor is below an acceptable pre-determined level in that region. Experience to date has shown that power factor correction has not been an issue with the installation and operation of ASDs. In the rare case, that power factor correction may be required, inexpensive power factor correction capacitors can be easily be installed at each motor, and sized as required.
The Flux Drive is a mechanical device incorporating a simple design, with long life bearings that are serviceable and will easily last the lifetime of the motor, which can be 20 – 30 years. The Flux Drive is 100% re-buildable, unlike a VFD that can often be obsolete after 2 – 5 years. We estimate that over a 20 year period the average VFD user will have to replace a VFD every 3 to 5 years. That is roughly 4 VFDs to 1 Flux Drive over the life time of the application.
The Flux Drive coupling and ASD are designed for long life (>20 years) with standard off the shelf bearings that are serviceable for life. In addition, the device does not have any torque bearing parts that touch between the magnetic can (on the input shafting) and the induction rotor (on the output shafting). The Flux Drive transfers torque through the air gap via magnetic flux transfer of torque / power. Coupling failures from misalignment or high torque loading / pulsations are now eliminated.
Typical ROI is 18 – 30 months (not including energy saving rebates). Power providers often provide grant rebates for saving power that can pay up to 70% of the total installation costs and reduce the ROI to months from years.
While magnetic coupling technology can have higher up-front costs compared to electronic VFDs, the ROI and Total Cost of Ownership analysis show that there is more value for the dollar spent on the Flux Drive technology than the traditional VFD technology. While the VFD’s “off the shelf” price may look appealing, the hidden costs to install, maintain and replace is far more expensive than the Flux Drive magnetic technology.
The Flux Drive ASD is a mechanical device that is simple, with long life bearings that are serviceable and will easily last the lifetime of the motor system. The Flux Drive ASD is 100% re-buildable, unlike a VFD that is typically obsolete after 5 years. We estimate that over a 20 year period, the average VFD user will have to replace a VFD every 3 to 5 years. That is 4 – 5 VFD’s to one (1) Flux Drive ASD over the lifetime of the application.
Other factors influencing Total Cost of Ownership of a Flux Drive ASD: