Yaskawa Whitepaper: The I’s and O’s of VFDs

Electromagnetic interference (EMI) is the degradation of the performance of equipment caused by electromagnetic disturbance. An example of EMI, is the noise on a microphone, if there is a cell phone next to it doing a handshake with a communication tower to process a call. In this example the cell phone is the source of the interference and the microphone is the victim equipment.

Potential ways to save energy can be found in almost all sectors, like building services, conveyor belt systems or chemical processes. The life cycle costs of an application can be roughly divided into four parts: the initial investment cost, the cost for the operation and maintenance of the application, the cost of the energy required by the application and the disposal cost at the end of the life cycle of the application.

Variable speed drives, due to their operating principle, produce a series of unwanted secondary effects, such as: motor winding isolation stress, bearing stress, acoustic switching noise in the motor and electromagnetic interference. In most applications these effects are at an acceptable level – but in some cases these effects need to be mitigated.