In the field of electric motors and industrial applications, companies rely on their equipment to operate normally and efficiently. Variable frequency drives (VFD) are used in motor applications such as pumps and forced draft fans to control fluid and airflow. They rely on them to keep the production line running. Whether the system uses VFD or throttling control will affect efficiency. Either way, when production stops or slows down due to mechanical failure, the pressure to solve the problem and resume efficient production increases.

VFD is a kind of motor control, which drives the motor by changing the frequency and voltage of the power supply. The VFD can also control the ramp-up and ramp-down of the motor during start or stop, respectively.

The VFD controls the speed of an alternating current (AC) motor by changing the frequency provided to the motor. The first step in this process is to use a rectifier to convert the AC mains voltage to direct current (DC). The DC power supply contains a voltage ripple smoothed by a filter capacitor. The driver then uses insulated gate bipolar transistors (IGBTs) to turn on and off the DC bus to generate variable frequencies.

VFD is used in everything from small appliances to large compressors. Since nearly 25% of the world's electrical energy is consumed by electric motors in industrial applications, systems that use VFDs are more efficient than systems that use fluid flow throttling control. As the efficiency of applications using VFD has improved, many companies have decided to upgrade to VFD from other systems.

VFD is common in wastewater stations that transport sewage. They are used to control the flow of sewage through the pump and help the sewage treatment plant successfully achieve the required flow.

VFD provides improved and precise process control and regulation for motors used in industrial applications. There are many benefits of using VFD in industrial applications, but the biggest benefit is energy saving. The VFD allows the operator to match the speed of the motor to the process requirements. When the flow rate or head pressure decreases, energy can be saved. The VFD also allows a bypass function to protect equipment from damage caused by power outages and other emergencies. In addition, the VFD provides overload current protection and safe and precisely controlled motor acceleration.

Troubleshooting behind the scenes can be a useful task. When following the steps listed on the right, a problem occurred with the VFD, production started, and efficiency improved. Usually, this list of basic troubleshooting tips can solve the problem. When troubleshooting does not provide an answer, please contact a reliable maintenance partner.

Wayne Hall is the Vice President of Engineering at Jenkins Electric Company. You can contact him at whall@jenkins.com. For more information, please visit www.jenkinselectric.com.