V/f Control 2A 15KW 3-Phases Motor VFD/VSD AC Drive For Driving Screw Pump Control

How does a VFD work?

The first stage of a Variable Frequency AC Drive, or VFD, is the Converter. The converter is comprised of six diodes, which are similar to check valves used in plumbing systems. They allow current to flow in only one direction; the direction shown 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, then that diode will open and allow current to flow. When B-phase becomes 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 negative side of the bus. Thus, 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 system. The 480V rating is “rms” or root-mean-squared. The peaks on a 480V system are 679V. As you can see, the VFD dc bus has a dc voltage with an AC ripple. The voltage runs between approximately 580V and 680V.

We can get rid of the AC ripple on the DC bus by adding a capacitor. A capacitor operates in a similar fashion to a reservoir or accumulator in a plumbing system. This capacitor absorbs the ac ripple and delivers a smooth 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 actual voltage will depend on the voltage level of the AC line feeding the drive, the level of voltage unbalance on the power 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, 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 usually referred to as an “inverter”. It has become common in the industry to refer to any DC-to-AC converter as an inverter.

Product advantages

1. Energy saving

2. Soft starter

3. Machines operating protection

4. Automation control

5. Enhance the production efficiency

VFD application range: Fans, Blowers, Turbines, Blast furnace, Water Pumps, Oil pumps, Plastic extruders, Granulating machine, Industrial production lines, Industrial washing machines, CNC machine, Spinning frame, Roving frame, Dyeing and printing machinery, Escalator, Medium requirement applications, Crane application, Metal cutting machine...

FAQ:

Q: Are you a trading company or manufacturer?
A: We are the factory.

Q: Do you provide samples? is it free or extra?
A: Yes, we could offer the sample to test with reasonable charges. We can send the sample to you by expresses like DHL or UPS, normally you can receive the sample in
one week.

Q: What are your terms of payment?
A:100% in advance before the shipment, T/T, L/C, Paypal are all acceptable.

Q: What are your terms of packing?
A: Generally, We use carton box pack low rated power VFD, VFDs that are 37KW and above are packed by wooden box. And we can add turn-over cartons for safety delivery, reasonable special packing requirements from customers are acceptable for us.

Q. Do you test all your goods before delivery?
A: Yes, 100% test before delivery, we can provide the test report for each model.

Q: How long is your delivery time?
A: Generally we have 10pcs per model in stock. or 10-15 days if the goods are not in stock, it is according to quantity.