Some of the improvements attained by EVER-POWER Variable Speed Motor drives in energy performance, productivity and procedure 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 enable sugar cane vegetation throughout Central America to become self-sufficient producers of electricity and increase their revenues by as much as $1 million a season by selling surplus power to the local grid.
Pumps operated with adjustable and higher speed electric motors provide numerous benefits such as greater range of flow and head, higher head from an individual stage, valve elimination, and energy saving. To attain these benefits, nevertheless, extra care must be taken in selecting the correct system of pump, engine, and electronic motor driver for optimum conversation with the procedure system. Successful pump selection requires knowledge of the full anticipated selection of heads, flows, and specific gravities. Electric motor selection requires appropriate thermal derating and, at times, a complementing of the motor’s electrical characteristic to the VFD. Despite these extra design considerations, variable speed pumping is now well approved and widespread. In a simple manner, a discussion is presented about how to identify the huge benefits that variable quickness offers and how 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 comprised of six diodes, which act like check valves found in plumbing systems. They allow current to circulation in only one direction; the path 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 stage voltages, then that diode will open up and invite current to movement. When B-stage becomes more positive than A-phase, then the B-phase diode will open and the A-stage diode will close. The same is true for the 3 diodes on the negative side 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 functions in a similar fashion to a reservoir or accumulator in a plumbing system. This capacitor absorbs the ac ripple and provides a clean dc voltage. The AC ripple on the DC bus is normally significantly less than 3 Volts. Therefore, the voltage on the DC bus turns into “around” 650VDC. The actual voltage will depend on the voltage degree of the AC collection feeding the drive, the level of voltage unbalance on the energy system, the 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 known as a converter. The converter that converts the dc back to ac is also a converter, but to tell apart it from the diode converter, it is generally known as an “inverter”.
Actually, drives are an integral part 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, oil and gas, power generation, and pulp and paper.