Variable Frequency Drives (VFDs)

Save 20-50% on energy costs and gain reliable control of your mechanical equipment!

Save Big with Installation of Variable Frequency Drives!

While constantly expected to do more with less, managing energy consumption and optimizing occupant comfort remains of utmost importance to facility managers. Products that integrate seamlessly into existing equipment and building management systems are also essential. Sander Mechanical’s variable frequency drive (VFD) portfolio can deliver all of this and more.

What are Variable Frequency Drives or VFDs?

A variable frequency drive (also termed variable-speed drive, adjustable-frequency drive, adjustable-speed drive, AC drive, micro drive, or inverter drive) is a type of electric motor controller used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage. Motors are usually sized for maximum demand volume, but typically need to operate at this level only a small percentage of the total operating time. For this reason, VFDs are an incredibly effective tool for achieving energy savings by reducing motor speed, volume, and power usage to match actual load requirements.

VFDs can be utilized effectively on a variety of equipment:

  • Air Handling Units
  • Return & Supply Fans
  • Exhaust Fans
  • Centrifugal Pumps
  • Domestic Water Booster Pumps
  • Cooling Tower Fans
  • Condenser Water Pumps
  • Centrifugal Chillers
  • Primary / Secondary Chilled Water
  • Boiler Feed Pumps

For example, cutting fan speed in half with a VFD lowers the required horsepower by a factor of eight, as fan power is proportional to the cube of fan speed. So depending on motor size, the energy savings (combined with energy efficiency incentives and utility rebates) can often payback VFD installations in less than one year.

Benefits of using Variable Frequency Drives VFDs

Reduce Energy Consumption and Operating Costs

Variable Frequency Drives allow for the precise matching of the speed of motor-driven equipment to the load requirement, thereby reducing energy consumption by as much as 50%. There is no other method of AC electric motor control that allows you to accomplish this.

Extend Equipment Life and Reduce Maintenance

Optimal motor application speed and elimination of short cycling, ensures equipment will last longer and have less downtime due to maintenance. Optimal control of frequency and voltage also offers better motor protection from issues such as electro thermal overloads, phase protection, under voltage, and overvoltage.

Soft Starting and Reduction of Inrush Current

Loads started with VFDs can have smooth acceleration and deceleration cycles, rather than subjecting motors to the “instant shock” of across the line starting. Reduction of mechanical stress eliminates belt, gear, and bearing wear. Substantial reduction of amps required during motor startup lowers peak demand charges.

Increase Production through Tighter Process Control

For manufacturing applications, operating motors at the most efficient speed for the application means fewer mistakes and increased production levels. For example, on conveyors and belts, jerks on start-up are eliminated, allowing high through-put and reduced production costs.

Improve Temperature Control for HVAC Systems

Tighter control of return temperatures with VFDs means AHUs and chillers can modulate the flow of conditioned air and water throughout a building with a much higher resolution, creating a more consistent temperature and humidity level.

Reduce Audible Noise

Slower speeds translate to less noise output and vibration from fans and pumps, lowering occupant disturbance and improving occupant comfort.

Sander installs and services VFDs from all of the major drive manufacturers, including Siemens, Danfoss, ABB, Yaskawa, & Honeywell.


Our VFDs offer the following features and advantages:

  • Latest, retooled drives are built to last
  • Energy savings of up to 50% when operating fans and pumps
  • Drive sizes ranging from 1 to 1,550 horsepower (hp)
  • Expanded I/O offers improved flexibility
  • Conventional and Electronic Bypass options available, providing peace-of-mind to customers in mission critical facilities
  • Advanced keypad with intuitive user interface; start-up wizards; and easy-to-use, read, and understand multi-line graphics / display
  • User friendly “hot swappable” control panel allows for quick replication of settings when programming multiple drives
  • Reliable control for a wide range of HVAC applications, including special control options in the event of fire (that overrides motor protection diagnostics to keep escape routes free of smoke).
  • Easy network integration with Building Management Systems using today’s open protocols (e.g. BACnet, Modbus, LON, etc.); embedded RS485 and Ethernet HVAC protocols
  • Communication built right into the drive, eliminating the need for a cabinet, power supply, converter, or extra cabling
  • Diagnostic alert function simplifies maintenance of motors, pumps and fans by informing staff when a belt is broken or a pump is empty or jammed, reducing the time it takes to diagnose and fix a problem
  • Onboard kWh meter monitors energy consumption and enables calculation of actual savings
  • Integral disconnect switch
  • Smaller footprint fits better in tight spaces

Click the links below for additional product information on the latest BT300 drives from Siemens and VLT drives from Danfoss:

Siemens BT300 Variable Frequency Drives (VFD) Brochure
Siemens BT300 VFDrive with Conventional or Electronic Bypass Brochure
Danfoss VLT HVAC Advanced Drive FC-102 Fact Sheet
Danfoss VLT HVAC Basic Drive FC-101 Fact Sheet
Danfoss VLT Drives – HVAC Product Overview
Danfoss VLT HVAC Variable Frequency Drives Brochure

Start saving! Contact Sander today for a free evaluation on which VFDs are right for your particular application.

Pumps Controlled by Variable Frequency Drives - VFDs
Danfoss Variable Frequency Drives - VFDs
Siemens Variable Frequency Drives - VFDs