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    Variable Frequency Drive

    Uploaded by

    cherif yahyaoui

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Variable Frequency Drive

    Uploaded by

    cherif yahyaoui
    28 views5 pages

    Copyright

    © © All Rights Reserved

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    PDF, TXT or read online from Scribd

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    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    28 views5 pages

    Variable Frequency Drive

    Uploaded by

    cherif yahyaoui

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 5

    Variable Frequency Drive

    What is VFD
    • A type of motor controller that drives an electric motor by varying the 
    frequency and voltage supplied to the electric motor.

    • VFD are variable speed drive, adjustable speed drive, adjustable 


    frequency drive, AC drive, Microdrive, and inverter.

    • If an application does not require an electric motor to run at full 
    speed, the VFD can be used to ramp down the frequency and voltage 
    to meet the requirements of the electric motor’s load.
    How does 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.
    What the different parts of a drive look like?
    Why to use VFD?
    1. Reduce energy consumption and energy cost ‐ Electric motor systems are 
    responsible for more than 65% of the power consumption in industry today. Optimizing motor 
    control systems by installing or upgrading to VFDs can reduce energy consumption in your 
    facility by as much as 70%.

    2. Increase production through tighter process control – By operating your 
    motors at the most efficient speed for your application, fewer mistakes will occur, and thus, 
    production levels will increase, which earns your company higher revenues. On conveyors and 
    belts you eliminate jerks on start‐up allowing high through put.

    3. Extend equipment life and reduce maintenance ‐ Your equipment will last 
    longer and will have less downtime due to maintenance when it’s controlled by VFDs ensuring 
    optimal motor application speed.

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