What Are the Advantages of Using Low-Voltage vs. Medium-Voltage Drives?

There are many advantages of using a low-voltage VFD over a medium-voltage drive.

(3-minute watch time)


Hello, everyone. My name is Justin Woodrum. I’m an electrical engineer for SPOC Automation. I’ve got 20 years of experience in engineering controls and automation, and today I want to talk to you about the advantages of using a low-voltage VFD over a medium-voltage drive.

In today’s market, customers are looking for ways to cut costs. That totally makes sense. One of the easiest ways to do that is to use a 480v VFD over a 4160v VFD. The lower-volt drive will save you money primarily in three ways.

First, the initial purchase and installation of the drive. Secondly, the operational costs of the drive. And lastly, the maintenance costs of the drive.

It’s no secret the medium-voltage drives cost a lot of money, but how much more over the low-voltage equivalent? On average, the initial purchase and installation of a medium-voltage drive will cost 60 percent more than the equivalent low-voltage VFD. The VFD itself cost more than double a low-voltage VFD.

In operational costs, for applications using motors of 1,000 horsepower or less, low-voltage VFDs operate more efficiently. These higher efficiency numbers account for lower power bills. Significantly lower.

And lastly, the maintenance costs of the drive. Before I worked in the oil and gas industry, I worked in the power industry as a control supervisor over a controls-engineering group. And the power company always used the big names in medium-voltage VFDs because that’s what they purchased. (This attitude of “that’s the way we’ve always done it” is common in the oil & gas business too!)

And every year, they would enter into very large, costly maintenance agreements and the power company was glad to do that because of the risks involved with the higher-voltage VFDs. The risks came in two ways: the physical risk to people, their in-house electricians, and also the risks to their equipment. When you buy a medium-voltage drive, you are making a sizeable investment!

What SPOC Automation provides for free to their customers in maintenance advice and technical advice over the phone — that same service would cost hundreds of thousands of dollars in the power industry.

So, as you can see with all these things in mind, for most applications, if you are running motors less than 1200 HP, there really is no reason to use a medium-voltage drive over a low-voltage drive. I hope you enjoyed this presentation and it was informative to you.

I hope you’re doing well and as always, pump long and prosper.