Variable Speed Drives

Variable Speed Drives

If you’re looking for ways to save energy – lets be truthful, who isn’t? – The Variable Speed Drive (VSD) is one of the most effective tools at your disposal.


While some machinery needs to run at a particular speed, many applications have different procedures that require different speeds.


Also known as Adjustable Speed Drives (ASDs), frequency converters, drives or inverters, VSDs are a highly effective way of utilizing energy more efficiently – with associated benefits including helping you to hit environmental targets, increasing profit margins and cutting costs.


Variable Speed Drives do- What do they do?


Essentially, they control the electrical supply to an AC induction motor, adjusting the motor speed and torque to match the process requirements of the machine by converting an electrical supply into a variable frequency and voltage. Most are controlled automatically.


Variable Speed Drives- How do they function?


The Variable Speed Drives used in AC induction motors are the most commonly used VSDs. They include: a rectifier for conversion of AC to DC current; an intermediate circuit to condition the rectified DC supply; an inverter to change DC back to an AC supply of variable voltage and frequency; and lastly a control unit to respond to external signals and monitor the system to ensure that the right output is given.


How efficient are Variable Speed Drives?

They are 92-98% efficient.


Are there any other advantages of Variable Speed Drives?

Even though most companies want to install VSDs for their money and energy saving attributes, there are other advantages, such as:

  • More accurate control of pressure, speed, temperature, and flow
  • Enhanced power factor
  • More control at high speed – sometimes higher achievable speeds
  • The possibility of linking with other process control systems
  • Prolonged tool life from soft starting and programmed deceleration or acceleration
  • Getting back electrical energy from braking for reuse


Grammar Electrical provides a wide range of variable speed drive products to meet a wide array of applications from simple variable torque to complex industrial applications which include machine controls, mixers, and conveyors. All products offer several options and onboard controls. Our VSD line also comprises liquid cooling for harsh environments.


To schedule a visit from Grammar Electrical’s expert VSD service, contact us or complete this service request form. You’ll be glad you did.

To schedule a visit from Grammar Electrical, contact us or complete this service request form. You’ll be glad you did.