VFDs offer cost-effective benefits for plants

Variable frequency drives (VFDs) are designed to reduce energy usage by controlling the speed of the motor and can offer cost-effective benefits for plants.


Variable frequency drives (VFDs) are designed to reduce energy usage by controlling the speed of the motor and can offer cost-effective benefits for plants. Courtesy: L&S ElectricMost business owners are aware of the high cost of operating electrical motors, but there are ways to reduce the costs. Improving the efficiency of an electric motor will save money in the long run, but it is important to understand that not every choice is going to be the right choice for every application.

An example of one way that many businesses can save money in energy costs is through installing variable frequency drive (VFD) technology. VFDs are designed to reduce energy usage by controlling the speed of the motor. While useful, they aren't always the best solution. There will be cases when VFD's cost and installation overshadow the savings they can provide to companies.

Understanding VFD technology benefits

A VFD's primary benefit is adjusting the speed of an ac motor by adjusting the available voltage. When the speed is adjusted, it helps to improve the efficiency of the motor, primarily by adjusting the output of the pump to match the flow and pressure requirements.

Any pump system that has a dynamic demand is a good choice for installing a variable frequency drive. If the pump operates at a lower flow than what is possible from the ac motor, controlling the motor with a VFD considerably reduces the energy consumption.

Installing a VFD can also extend the life of the motor by reducing mechanical wear, which, in turn, reduces maintenance costs, replacement costs, and can keep the motor running at high efficiency.

Is a VFD needed for the application?

A VFD is not always going to be the best choice for every design. Energy and cost savings need to be calculated to determine if it beneficial. This requires the operator to determine the minimum to maximum pump operation, estimate how long the pump would run at various speeds, and estimating how much energy is used at each flow rate.

When considering the costs associated with VFD installation, the operator also needs to consider the cost of the VFD and any potential rebates offered through the utility company for installing it. Factor in any reduction in expenses for maintenance or replacing the pump due to extended pump life from operating at lower speeds.

During a new installation, the benefits of a VFD are usually obvious. In a retrofit, however, there may be additional factors to consider, such as a larger footprint than a motor starter as well as the cost of power cables that may be necessary for the installation as well. In many cases, VFDs can help facilities save money once they are installed and utilized to their fullest potential.

- David Manney is a marketing administrator at L&S Electric. This article originally appeared on L&S Electric Watts New BlogL&S Electric Inc. is a CFE Media content partner.

Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
June 2018
2018 Lubrication Guide, Motor and maintenance management, Control system migration
May 2018
Electrical standards, robots and Lean manufacturing, and how an aluminum packaging plant is helping community growth.
April 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
June 2018
Machine learning, produced water benefits, programming cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
February 2018
Focus on power systems, process safety, electrical and power systems, edge computing in the oil & gas industry
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
April 2018
Implementing a DCS, stepper motors, intelligent motion control, remote monitoring of irrigation systems
February 2018
Setting internal automation standards

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
Maintenance & Safety
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me