What Is A Variable Speed Drive?
A variable speed drive is a device which helps to regulate the speed of a motor by varying the electrical supply. As a result, variable speed drives are extremely good at making sure that conventional motors have adequate cooling and do not overheat.
What Are Variable Speed Drives Used For?
Variable drives are used to control the speed of motors. Conventional motors are controlled by using a value to adjust the flow of fuel. The flow of fuel can be altered, the speed of the motor remains unchanged. Although there are some solutions which try to work around this problem by having two-speed settings or temporarily interrupting the supply of fuel, these methods are largely inefficient from an energy usage standpoint.
A variable speed drive solves this problem by allowing the flow of current to a motor to be finely adjusted. More current will induce the motor to go faster, while less current will have the opposite effect.
Situations In Which To Use A Variable Speed Drive
Motors are used throughout industry. In fact, it is estimated that motors consume more than 65 percent of industrial electricity. They’re employed in hundreds of applications, including:
- Ski lifts
- Conveyor belts
- Plant machinery
- Ventilation systems
- Paper machines and fans.
Benefits Of Variable Speed Drives
Reduced Energy Usage
It is estimated that electrical motors consume more than 115 million MWh of electricity every year. That’s the equivalent energy output of more than 14 nuclear reactors.
But because variable speed drives are able to control the quantity of electrical power used by a motor, they can be used to decrease energy usage. By adjusting energy usage to requirements, the average plant running a 30 kWh motor for 5,000 hours a year could save in excess of 76,500 kWh electricity compared to using a damper.
Compatible Across Motors
One concern is that variable speed drives are not compatible across motors. But pulse width modulation drives (PWD) are used in applications ranging from as little as 0.5 HP all the way up to 500 HP. There are other types of variable frequency drives too, such as source inverters (CSI) and voltage source inverters (VSI), all of which are suitable for particular applications. Some drives are as small as a milk carton, others as large as a car. There are drives for single motor applications, as well as multi-motor setups.
Can Ride Out Power Losses
If power output dips by a small amount, many variable speed drives are able to continue working, feeding power to equipment and preventing downtime.
Variable speed drives are constructed in a way that makes them highly efficient. Pulse width modulation drives, for instance, are able to run at between 92 and 96 percent.
Better Process Control
With better voltage control, variable speed drives allow you to ramp up or ramp down operations as needed. Motors can be programmed to run at precise speeds or to stop at an exact time.
Increased Equipment Life
Starting up a single speed motor subjects it to high initial torque. With a variable speed drive, torque can be increased gradually, reducing wear and tear.