VFD Programming and Parameter Setting

What is a VFD in HVAC?

A variable frequency drive is an electronic device and a motor controller. It is used to control motor speed and this speed is controlled by changing frequency. However, what does VFD stand for in HVAC, VFD is a variable frequency drive and HVAC is a high voltage alternating current. VFD can be used for high-voltage applications and VFD used for AC motors. In most cases, VFD is used to control the high-power three-phase induction motor. Sometimes motors need to fluctuate speed, if you use variable frequency drive then you can easily fluctuate motor speed by changing frequency. There are many benefits of using VFD in HVAC. However, let’s see how to do VFD programming and VFD parameter setting.  

VFD Installation and Wiring

VFD installation and wiring is the most important part before VFD programming and VFD parameter setting. However, first of all, you need to decide on a VFD and open the VFD cover. Remove the cover where input and output ports are available. In this case, you need to keep the focus on the VFD installation requirements that you must need to know. 

  • First of all, you have to confirm that your VFD power and control terminal is clear.
  • Whenever you wire the VFD then don’t connect it to the power line.
  • You have to make sure that you have connected the input (suppose L1, L2, L3) and output power line (R, S, T) correctly.
  • The major thing is that before wiring the VFD you must see the VFD manual wiring diagram. 
  • Follow the wiring diagram from the VFD manual book and connect the input, output, and some other connections correctly. 
  • Make sure that all the units must be grounded to prevent electric shock.
  • Make sure that you have wired correctly with both input and output terminals.
  • No loose wire is available and there is no short circuit between the terminals
  • At the final stage, you must check that you have done all the things correctly.

It is noted that the user must connect the wire by following the VFD wiring diagram. Most of the VFDs have PLC-to-motor communication ports on the keypad. This port is for communication purposes between PLC and the motor. If you would like to wiring a VFD to a 3 phase motor you have to do the same thing as a single-phase motor. But you have to connect a phase and neutral for a single-phase motor but you have to connect a three-phase supply line to the VFD.

On the other hand, VFD control wiring means VFD is controlled by wiring VFD to motor. VFD control wiring is connected supply line of the three phases of motor L1, L2, L3, potentiometer, reverse/forward switch connection, multi-step switch connection, breaking resistor connection, and others. Basically, you should wire the VFD based on the manual. If all the connection becomes correct then your motor is ready to run. 

Variable frequency drive programming

Variable frequency drive is sometimes called variable frequency control drive. However, if we would like to run the motor by using VFD we must require simple programming which is called variable frequency drive programming or VFD programming. In this case, you don’t need to make coding to do AC drive programming. You have to set the parameter by using the VFD manual and motor nameplate. First of all, you may need to set up some basic parameters of VFD and AC motor such as 

  • Constant frequency
  • Variable frequency
  • Ramp up time
  • Ramp down time
  • AC motor frequency
  • Motor voltage
  • Current 
  • Motor total power
  • Motor direction (forward/reveres).

These are the simple and common VFD basic parameters that you need to set up all the VFD whenever you run the motor. However, you have to set that parameter by using the VFD keypad button. If you can successfully set the parameter then you can press the start button to run the AC motor. It is noted that whenever you use VFD on any brand then you must use a manual to set the parameter or programming. 

What does VFD stand for in an electrical sense?

What is the meaning of VFD what are VFDs used for? It is a very common question let’s find the answer to this question. VFD is a variable frequency drive that is a rotating electronic device that controls the motor speed by changing the frequency. It is sometimes called an AC motor controller. VFD is used to start a motor with a smooth startup or ramp-up, preventing overload whenever the motor becomes starts. If you want you can run the motor based on your desired speed and this is possible by changing the frequency. VFD operation is greatly used in the industry to control the motor speed and run the motor at any desired speed. 

How to do VFD parameter setting?

The Ac drive parameter setting is the same thing for all the VFDs. It means if you would like to run the motor by using a variable frequency drive then you have to set the parameter. There is a common VFD parameter list that you must set up and it is mandatory for all the VFDs

  • Motor frequency
  • Motor voltage
  • Current 
  • Motor total power
  • Motor direction
  • VFD overload current setting
  • VFD drive parameter setting
  • VFD frequency setting
  • VFD’s current limit setting

It is noted that these are the common factor for all types of VFDs. On the other hand, if you want to do the multifunction then you can do that. Basically, it depends on you how you will run the motor. It is noted that whatever you do you must set the above parameter to run the motor smoothly. You must remember that if you set up the VFD parameter then you must follow the VFD manual. So insert the parameter whatever you need by following the VFD manual.

How to program VFD with PLC?

How to connect VFD to PLC? It is a simple connection. If you would like to connect VFD to PLC then see the VFD connection manual. This connection manual will lead you through how to connect VFD to PLC. However, PLC and VFD can be connected in two ways. First of all, you can use the terminal connection to connect between them.

In this case, you need to connect the PLC output terminal with the VFD input terminal which is called a terminal connection. On the other hand, you can connect the PLC with VFD by a communication port like RS485. However, to get a complete conception you must see the VFD connection diagram before wiring. 

How does VFD control motor speed?

How does a VFD control motor speed? There is a straightforward answer to it. VFD controls motor speed by frequency changing. However, let’s explain it. Most of the industry uses variable frequency drives for 3 or single-phase motors to control their speed. In this case, you need to insert the parameter that we have given above. If you set up all the parameters correctly then you can press the VFD run switch.

If you press it then your VFD will be started and the motor will reach the selected speed through the ramp-up time. Now you can change the frequency and you can keep it on your desired point. It is noted that a question comes to mind what is the use of VFD in the HVAC system? The straightforward answer is VFD is specially designed for AC or HVAC systems.

How does a VFD work on a motor?

How do inverter drives work? The VFD is an acronym for Variable Frequency Drive. The VFD does this by changing the frequency of the electric power to the motor. The VFDs are also known as inverters, variable-frequency controllers, or variable-voltage sources. They are used in applications where it is not possible or desirable to run motors at a fixed speed.

A VFD is a type of motor speed controller that can change the speed and torque of a motor. This is done by varying the voltage, frequency, or phase angle input to the engine. A VFD works in conjunction with other components to provide a particular function. For example, they are often used as part of an inverter that converts DC power from solar panels in an efficient way or wind turbines into AC power for use in homes or businesses.

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