How Do I Choose a Variable Speed Drive?

Once you have made the decision to invest in a Variable Speed Drive, also referred to as a VSD, the problem of what size you should get becomes a challenging decision. Choosing the correct sized VSD is paramount to ensure that the desired level of efficiency and productivity is reached and maintained.

There are multiple factors to consider when choosing the correct size of Variable Speed Drive. In this article, we will list and explain all of the factors, answering the question of; “how do I choose a Variable Speed Drive”?

The Definition of a Variable Speed Drive

There are multiple names for a Variable Speed Drive; thus, it is also known as a Variable Frequency Drive, AC Drive, Microdrive, Inverter, and Adjustable Speed Drive.

A VSD changes and controls the speed of an electric motor. It does this by adjusting the frequency and input voltage supplied to the motor. The adjustment of the motor speed is performed to fulfil the requirements of the application for which it is used.

Choosing the Correct Size

There are varying factors to consider and take into account when deciding on the best size of VSD for your specific application. The factors to be considered include:

The Type of Application: It is important to determine whether your application type is variable or constant torque. Each has separate ratings and all drive specifications are organised and based on these ratings.
Heat Generated: VSD’s generate a large amount of heat and if not managed can cause the temperature within the drive enclosure to exceed that of the recommended rating. This will also determine if you need to invest in an Air Conditioning Panel.
Location Altitude: The altitude at which the VSD is operating will also affect the heating and cooling of the drive as denser air is generally cooler.
Full Load Amperage: The drive must be able to take the full load current of the motor. This can be checked on the motor itself.
Overload: it is important to realise and cater for any overload condition that can and will occur. Thus, ensure that you include this in your calculation and ensure your drive can handle this easily.
Carrier Frequency: When comparing carrier frequencies, try to obtain one that is the lowest your motor can stand. This can typically be modified on the drive.

Variable Speed Drive Suppliers South Africa

At EP Normand we stock and sell a variety of VSD drives and can assist you in choosing the correct size for your specific application. Contact our team for more information.