Variable Frequency Drive Systems


Variable frequency drives are commonly used today in power generation systems and in industrial processing. They come into the picture when there is a need for converting fixed voltage and frequency to variable voltage and frequency. Among all the power conversion devices, they are the best source for saving energy as will be vouched for by all the variable frequency drive dealersThat is one of the main reasons for their popularity in the industrial sector.

VFDs are also referred to as variable speed drives or adjustable frequency drives. They come in three basic types which are current source inversion (CSI), voltage source inversion (VSI) and pulse-width modulation (PWM). They allow varying speeds to be selected within the range of their operation unlike the constant speed systems.They serve a number of purposes like preventing equipment problems like excess torque, motor burnout, shaft damage, wear on pumps and disturbances in power lines. They are put to good use in most machines which need to alter their speeds during their working to achieve better product quality besides working with higher levels of safety.

Several examples can be provided which shows the utility of the variable frequency drives; this information can also be provided by VFD dealers.

  • The first example is the case of a milling machine where the speed has to be altered while running the work pieces to maximize the cutting tool’s feed rate.
  • Another case is of the printing press, where speeds are altered depending upon the coating and weight of the paper in order to obtain high quality output.A smooth acceleration is facilitated by these drives as they prevent the web paper from breaking.
  • The VFD systems are highly useful in the operation of pumps which supply water to tall buildings. Different quantities of water have to be supplied in the course of the day to different occupants and the need for slowing down or speeding up can be easily facilitated through these drives.
  • Another important application where these drives prove useful is in the smooth working of lifts. The sudden jerks associated with the stopping or starting of lifts are avoided as these drives help to adjust the differing speeds when the lift gains acceleration.

In this context, a mention has to be made of equipment that is also useful here and that is the automatic electrical control panel. The automatic electrical control panel ensures the switching of power to the emergency standyby mode if there is a total blackout. This prevents the lifts from getting stranded mid-way. The sensors contained in the panel detect the failure of power and signals to the generator set to get working and supply the power. Variable frequency drives are a strong energy conserving power source while the automatic electrical control panel is a source that ensures continuity of power.

All this equipment needed for industrial processing can be bought on a wholesale basis through a renowned distributor or dealer. Diesel engine dealers, variable frequency drive dealers as well as the automatic electrical control panel manufacturers are the right sources for obtaining the equipment.