Variable Frequency Drive for Dust Extractor Fans

[VinnyGalbo]

I have heard different stories about variable frequency drive (VFD) for extractor fans. How do they work?

Sellers I’ve researched about the drive claim it will reduce electricity costs. I suppose it will reduce noise as well. I have spoken to two suppliers of ducting. They both say that it causes an increased risk of fire as shavings tend to build up in the ducting. They also say that extraction fans are designed to run at one frequency and varying the frequency makes the fan very inefficient.

Is this true?

 

[WorthFlorida]

This is the first time I heard of VFD. I googled search and https://en.wikipedia.org/wiki/Variable-frequency_drive has a good article on it.

Overall it seems the help on the start up of a motor. A slow speed up of RPM's to prevent the motor from drawing large slugs if current. But why would you want to have it in a piece of equipment that must operate a full speed or load to extract material. If you had a shop with a 100 motors there might be a savings but when you factor in the cost to buy a VFD device for one motor there may not be any benefit. You'll need to check that the AC motor you have will work with VFD. The statement above about "make the fan very inefficient" contradicts what VFD is all about.

A VFD manufacturer would see it, if they can get 1 million motors to get .1 % more efficient, then times the number of motors with VFD, it make a big statement on the reduced energy draw on the power grid. If your really serious about VFD, call on your supplier and ask for the factory rep to call you and extend an invitation to your place for a demo. You can then ask the questions. That's the job of a factory rep, train and support the suppliers and customers.