A few of the improvements achieved by EVER-POWER drives in energy efficiency, productivity and process control are truly remarkable. For instance:
The savings are worth about $110,000 a year and have cut the company’s annual carbon footprint by 500 metric tons.
EVER-POWER medium-voltage drive systems allow sugar cane plants throughout Central America to be Variable Speed Electric Motor self-sufficient producers of electricity and boost their revenues by as much as $1 million a year by selling surplus capacity to the local grid.
Pumps operated with variable and higher speed electric motors provide numerous benefits such as greater selection of flow and head, higher head from a single stage, valve elimination, and energy saving. To achieve these benefits, nevertheless, extra care should be taken in choosing the correct system of pump, electric motor, and electronic engine driver for optimum conversation with the process system. Effective pump selection requires knowledge of the full anticipated range of heads, flows, and particular gravities. Engine selection requires suitable thermal derating and, sometimes, a complementing of the motor’s electrical feature to the VFD. Despite these extra design factors, variable speed pumping is becoming well approved and widespread. In a straightforward manner, a debate is presented on how to identify the benefits that variable speed offers and how exactly to select elements for hassle free, reliable operation.
The first stage of a Adjustable Frequency AC Drive, or VFD, is the Converter. The converter is usually comprised of six diodes, which act like check valves found in plumbing systems. They enable current to movement in mere one direction; the direction shown by the arrow in the diode symbol. For example, whenever A-stage voltage (voltage is similar to pressure in plumbing systems) is more positive than B or C phase voltages, after that that diode will open up and allow current to stream. When B-phase becomes more positive than A-phase, then your B-phase diode will open up and the A-phase diode will close. The same holds true for the 3 diodes on the negative aspect of the bus. Therefore, we obtain six current “pulses” as each diode opens and closes.
We can eliminate the AC ripple on the DC bus with the addition of a capacitor. A capacitor works in a similar fashion to a reservoir or accumulator in a plumbing system. This capacitor absorbs the ac ripple and provides a smooth dc voltage. The AC ripple on the DC bus is typically significantly less than 3 Volts. Thus, the voltage on the DC bus turns into “approximately” 650VDC. The actual voltage depends on the voltage degree of the AC range feeding the drive, the level of voltage unbalance on the energy system, the electric motor load, the impedance of the power program, and any reactors or harmonic filters on the drive.
The diode bridge converter that converts AC-to-DC, is sometimes just referred to as a converter. The converter that converts the dc back to ac is also a converter, but to distinguish it from the diode converter, it is normally referred to as an “inverter”.
Actually, drives are a fundamental element of much larger EVER-POWER power and automation offerings that help customers use electricity effectively and increase productivity in energy-intensive industries like cement, metals, mining, coal and oil, power generation, and pulp and paper.