A Variable Frequency Drive (VFD) is a type of electric motor controller that drives a power electric motor by varying the frequency and voltage supplied to the electrical motor. Other brands for a VFD are variable speed drive, adjustable rate drive, adjustable frequency drive, AC drive, microdrive, and inverter.
Frequency (or hertz) is directly linked to the motor’s acceleration (RPMs). Basically, the quicker the frequency, the quicker the RPMs go. If a credit card applicatoin does not require a power motor to perform at full speed, the VFD can be used to ramp down the frequency and voltage to meet up certain requirements of the electric motor’s load. As the application’s motor velocity requirements change, the VFD can simply arrive or down the motor speed to meet the speed requirement.
The first stage of a Variable Frequency AC Drive, or VFD, is the Converter. The converter is certainly made up of six diodes, which are similar to check valves used in plumbing systems. They enable current to circulation in only one direction; the path demonstrated by the arrow in the diode symbol. For example, whenever A-phase 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 invite current to movement. When B-stage turns into more positive than A-phase, then the B-phase diode will open and the A-phase diode will close. The same is true for the 3 diodes on the adverse aspect of the bus. Hence, we get six current “pulses” as each diode opens and closes. This is called a “six-pulse VFD”, which is the standard configuration for current Variable Frequency Drives.
Let us assume that the drive is operating on a 480V power program. The 480V rating is usually “rms” or root-mean-squared. The peaks on a 480V program are 679V. As you can plainly see, the VFD dc bus has a dc voltage with an AC ripple. The voltage runs between approximately 580V and 680V.
We can eliminate the AC ripple on the DC bus by adding a capacitor. A capacitor works in a similar fashion to a reservoir or accumulator in a plumbing program. This capacitor absorbs the ac ripple and delivers a soft dc voltage. The AC ripple on the DC bus is typically less than 3 Volts. Thus, the voltage on the DC bus becomes “approximately” 650VDC. The real voltage will depend on the voltage level of the AC range feeding the drive, the amount of voltage unbalance on the energy system, the motor load, the impedance of the power system, and any reactors or harmonic filters on the drive.
The diode bridge converter that converts AC-to-DC, may also be 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 referred to as an “inverter”. It has become common in the market to make reference to any DC-to-AC converter as an inverter.
Whenever we close one of the top switches in the inverter, that phase of the motor is connected to the positive dc bus and the voltage on that phase becomes positive. When we close one of the bottom level switches in the converter, that phase is connected to the negative dc bus and becomes negative. Thus, we can make any phase on the motor become positive or adverse at will and can hence generate any frequency that people want. So, we can make any phase be positive, negative, or zero.
If you have a credit card applicatoin that does not need to be run at full rate, then you can decrease energy costs by controlling the motor with a variable frequency drive, which is one of the benefits of Variable Frequency Drives. VFDs enable you to match the swiftness of the motor-driven apparatus to the strain requirement. There is absolutely no other approach to AC electric electric motor control that allows you to do this.
By operating your motors at the most efficient velocity for your application, fewer errors will occur, and thus, production levels increase, which earns your business higher revenues. On conveyors and belts you remove jerks on start-up enabling high through put.
Electric electric motor systems are responsible for more than 65% of the power consumption in industry today. Optimizing electric motor control systems by setting up or upgrading to VFDs can reduce energy usage in your facility by as much as 70%. Additionally, the use of VFDs improves item quality, and reduces creation costs. Combining energy performance tax incentives, and utility rebates, returns on investment for VFD installations can be as little as six months.
Variable Speed Drive, the right option for you.