{"id":164,"date":"2018-07-26T16:23:59","date_gmt":"2018-07-26T16:23:59","guid":{"rendered":"https:\/\/www.letterofintent.biz\/?p=164"},"modified":"2021-11-11T09:59:08","modified_gmt":"2021-11-11T09:59:08","slug":"misconceptions-about-variable-frequency-drives","status":"publish","type":"post","link":"https:\/\/www.letterofintent.biz\/misconceptions-about-variable-frequency-drives\/","title":{"rendered":"Misconceptions about Variable Frequency Drives"},"content":{"rendered":"
VFDs are important and they have numerous benefits. However, there are some myths and misconception about the VFDs. The sad thing is that the myths interfere with the solutions provided by VFDs to various OEMs.<\/p>\n
VFD components <\/strong><\/p>\n As a fact, VFD panels<\/strong> share some common components such as output inverter section, bridge rectifier, DS bus capacitor bank, and soft-charging bank. The VFDs vary in their reliability of components, the switching of the inverter sections and the efficiency of thermal dissipation scheme. Some variable frequency drive panels<\/a><\/strong> achieve lower voltage intensification at the motor. This is because of the three level output as it makes it possible for the output pulse to change between full-bus level pulses, voltage-level pulses and half-bus. Other types of VFDs have matrix-style inverters which do not have a bridge rectifier or DC use. The VFDs use bidirectional switches which are capable of connecting to any one of the three output phases. This makes it possible to have a four-quadrant operation where power flows freely from motor to line or line to motor.<\/p>\n Control and Program <\/strong><\/p>\n Even though VFDs have many parameter settings, it does not mean you have to use all of them. Every application requires specific parameters. Therefore, you do not have to worry about other parameters that you may not use to set up your VFD.<\/p>\n Output is Sinusoidal <\/strong><\/p>\n When you use a motor starter to start an induction motor, it requires connecting the 3 phase leads to a 3 phase power. Each of the three phases has a frequency of 60 HZ and a 460 V, 230 V and 575 Volts of voltage amplitude. The voltage creates an equal sine wave current waveform which is equal to what is provided at the motor leads. VFDs output work differently. They change the 3 phase input into a dc voltage using dc bus capacitors to filter and store it. The dc voltage undergoes a transformation process where each output phases uses an insulated bipolar transistor. The process produces variable frequency output and variable voltage.<\/p>\n