• “I have a huge backlog, and I don’t have time to learn about it.”
• “A friend used it several years ago and had terrible luck, so I’m not going to use it.”
• Or, “My customers aren’t interested in that kind of technology, I’m sure of it.”

However, as we all know, these are excuses moreso than reasons for not learning about new technologies. Vfd’s, for instance, are a prime example of a great technology that many contractors don’t offer, often for reasons similar to those listed above.

And that’s not necessarily good. In truth, that’s b-a-d.

In other words, if you’re resting on one of the above excuses, it’s time to get moving on. More and more contractors are using vfd’s in a variety of applications.

It’s better to learn about vfd’s than lose customers, right?

Getting started

In case you’re unfamiliar with vfd technology, it’s very simple. The vfd is nothing more than a motor controller that varies the speed of a motor. It works by generating variable voltage and frequency output in the proper volts:Hertz ratio for the motors from a fixed power supply.

Vfd’s can save substantial amounts of energy when applied to variable-torque loads (such as fans and pumps), and result in reductions in electricity bills in most facilities.

Another benefit to the vfd is that it “soft starts” the motor, meaning the motor doesn’t have to start at its full-load potential. That soft start means less wear and tear on the motor, resulting in lower maintenance costs and longer motor life.

Mike Rapp, president of Binsky & Snyder Service, Inc., a commercial-industrial mechanical contracting firm in Piscataway, NJ, started using vfd’s about seven years ago. That’s when the energy management companies came to town and offered energy-saving services to large retailers in the area.

These companies would install controls that would start and stop the fans and pumps at various times to try to shed load. That, in theory, would cut down on the peak energy demand customers pay to the electrical utilities.

Rapp saw something else happening. “What these companies did was burn out large-horsepower motors at a fast rate. When you start and stop a 100-hp motor four or five times an hour, it heats up. Then it draws more and more amperage, and this higher amperage tends to overheat the windings.”

In response to the problems, Rapp started using vfd’s in an attempt to soft start the motor. “We saw that we could cut the demand charge to the customer because the ramp-up time was slower, and we could also vary the rate of the motor speed. By doing that, we didn’t see the need for vortex dampers. That’s what started getting us interested in using variable-frequency drives.”

Learning curve

Rapp didn’t just dive right into using vfd’s. He started by talking to friends who were energy management engineers, finding out how vfd’s worked, potential problems, how they would affect the system, etc.

“Some of the engineers I talked to have been using variable-frequency drives for 20 years. They made all the mistakes, and they’ll admit it to you. Somebody who says to you, ‘I’ve made every mistake that you could possibly make’ — that’s the guy you want to talk to. I don’t want to make the same mistakes he did.”

Manufacturers are another great resource. They sponsor classes all the time about vfd’s, because they want to give you their knowledge so you’ll buy their products. Rapp says it’s important for a principal of a contracting firm to attend these seminars, not just the technicians.

“The principal of a company has to go, because he’s got to understand the value of what it is he’s trying to sell his customers. If the contractor doesn’t attend, it’s ultimately a waste of time to send the technicians.”

Rapp cautions that it’s also very important to find a manufacturer with whom you’re comfortable. “I prefer to do business with the manufacturers who allow us to install, start-up, and service their drives. There are manufacturers out there who will sell you the drive, but they have a local company that is responsible for all their start-up and service.”

Scott Needham, vice president of Princeton Air Conditioning Inc., a commercial and residential contracting firm in Princeton, NJ, says the manufacturer’s representative is the person who influences him most regarding which vfd he’s going to purchase.

“The manufacturers’ reps are really the key component,” Needham says. “They need to be willing to come out to jobsites to help us figure out if a particular drive makes sense. They need to help us spec it and start it up. It’s really the representative I rely on.”

Makes sense on larger motors

Needham started using vfd’s about two years ago. He got involved when the price of the technology started coming down.

“There are only so many things you can do in this industry. Basically, you put in heating and air conditioning equipment, and you solve service problems. Here’s another little profit center, another product and service you can sell and install that adds to the bottom line. It offers an extremely good profit margin.”

But it goes beyond that, Needham notes. It’s also great for the customer. “You make good money on [vfd’s], but in the end, the customers are getting a good product, and it’s helping those customers achieve tremendous energy savings.”

In deciding whether or not an application can benefit from a vfd, Needham usually looks at the size and age of the motor. He has found that the payback makes the most sense on high-efficiency motors that are 10 hp or greater. If the motor is older and not considered to be a high-efficiency unit, Needham replaces that as well before installing the vfd.

He says he is interested in learning about vfd’s in smaller applications as well, but he’s not ready to jump into that market yet. “Once we upgrade and install vfd’s on all the larger horsepower motors in the area, then I’ll start looking at the smaller or fractional-horsepower motors. But I think there’s a huge opportunity with larger motors still out there in need of conversion.”

When asked why more contractors aren’t working with vfd’s, Rapp says he just doesn’t understand it. “As technical as we are in this industry, we seem to shy away from anything that’s technical.”

Needham agrees, although he notes, “I’m happy that more contractors are not involved with these types of products. It’s good for my business.”