Understanding And Basic Concepts Of Delta VFD

In this article, we are going to learn the basic concepts and understanding of Delta VFD (Variable Frequency Drive) with step by step practical demonstration high quality video tutorials. VFD is a variable frequency drive and in this article we will be learning about what is a VFD, what about its terminals and other basic things such as how to connect a three phase electric motor to VFD.

The drive which I am using here is, 1.5 kilowatt, and of Delta VFD (Variable Frequency Drive) M-Series. This is M-series, 2 HP (horsepower) drive,  I/P (input) should be 230 volts single phase, or you can also supply input three phase 440 volts. Input to this Delta VFD (Variable Frequency Drive) can be single phase, and it can be three phase.  There are three terminals in the top side of the Delta VFD (Variable Frequency Drive) which is known as input terminals of the drive, L1, L2 & L3. I have applied single phase 230 volts to this Delta VFD (Variable Frequency Drive), because it is very common in my place.

Complete Wiring of Delta VFD

From below terminals, there are three phase output which you have to connect to the motor for operation. Below is the diagram of how Delta VFD (Variable Frequency Drive) looks like and basic wiring diagram of Delta VFD.

Delta VFD Diagram

In this wiring diagram of Delta VFD (Variable frequency drive) given above, there are line and neutral terminals you can see on the top side of Delta VFD (Variable frequency drive). This terminals are for connecting the input supply to the Delta VFD (Variable frequency drive). You can connect single phase supply, as well as three phase input supply. For input controlling of the drive, you can connect a relay, and two push buttons for switching it ON and OFF. The single line diagram of this input controlling is also given above. This diagram is to start and stop the Delta VFD (Variable frequency drive).

Delta VFD (Variable frequency drive) Status Screen

Let's learn about the status screen of Delta VFD (Variable frequency drive). The function or purpose of using the VFD is to control the frequency. As we know, motor RPM is equal to 120 x Frequency by power. The frequency is directly proportional to the motor RPM.  So what does it mean? If your frequency is 50 hertz. Generally motor runs at 50 hertz frequency and in some place, it runs at 60 hertz. At 50 hertz, the maximum RPM is 3000 RPM.  Which means a 25 hertz' RPM will be 1500 RPM. Because frequency and the RPM is directly proportional which means if frequency will be increased, the RPM or speed of the motor will also be increased.

Also Read: Learn Allen Bradley VFD From Scratch

Alright, so above is the diagram of Delta VFD (Variable frequency drive) status screen with different situations. Let's discuss one by one.

1. The first screen is talks about the motor is OFF because the LED of red.
2. This is the frequency shown in the screen number 2, which we command from the drive nope.
3. Then, you have output frequency denoted by "H".  Click on the "MODE" button to find "H" command in the screen of Delta VFD (Variable frequency drive). "H" will be zero if motor stop.
4. The you have to set some parameter in the Delta VFD (Variable frequency drive), by which the drive will work as per instructions that you will give to the drive through the parameters. Parameters is denoted by "P".
5. There is some more functions such as direction of the motor (with this direction function, motor can be run in reverse direction or forward direction as well).
6. Amperes function will indicate you how much current is consuming by this motor.

Now we have some controlling terminals in the bottom side of the Delta VFD (Variable frequency drive). Below picture of the terminals of Delta VFD (Variable frequency drive) indicating that which terminals is used for what purpose.


Also Read: Learn Allen Bradley VFD From Scratch


Relay feedback terminals and three terminals by which we get relays feedback from the drive. In various cases, for example, your Delta VFD (Variable frequency drive) is running and  this can be use for getting the feedback, when your Delta VFD (Variable frequency drive) is stop, if there is any fault, your motor is consuming higher current or any other problem in the operation. In the last of control terminals, there are "MCM and MO1" terminals which are also feedback terminals.

I hope this information is enough to understand the basic concepts of Delta VFD (Variable frequency drive). Please watch this video tutorial with practical demonstration of understanding of Delta VFD (Variable frequency drive).