A Short History of AC Drives

23rd July 2013 | Posted by Charlotte Miskell

The induction motor was developed by Nikola Tesla in 1924, and has the innovative characteristic that it can be run through a direct connection to a three phase power source.  Soon after AC drives were developed, varying the speed was the next idea to be considered.  The only practical way that this could be done was to create a variable frequency by using a DC motor turning an AC alternator which provides a variable frequency.  These kinds of operating systems were still in use until the mid 1980s, when they were replaced with static variable frequency controls.  The design of these AC drives which turned out to be the most popular were those based on the six step variable voltage principles.   This design is less widely used today, with favour being carried with the sine coded PWM drives.


Not all VFDs are the same, and it is important to carefully weigh up your specified plant requirements prior to selecting which variable speed drive to install.  There are a range of different specifications for different capabilities, so it is important to make sure that whichever AC drive you choose for your requirements is neither over, nor under specified.


Thinking of having a variable speed drive installed? Speak to Proplas International today!

At Proplas we supply and install variable speed drives for both commercial and domestic users, ensuring that the AC drives are matched up with your industrial requirements.  If you are simply looking for advice on the correct drive to suit your needs, or need help locating the correct VFD for you, our engineers can take you through the whole process from selection to installation.  If you wish to speak to our team, then call 01282 872 450 or alternatively contact us online today!

AC drives
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