Also known as variable frequency drives (VFD), variable speed drives, adjustable frequency drives, AC drives, micro drives, or inverter drives, they’re used to control electric motor speed and torque. Much like a soft start, low voltage variable frequency drives can control stop and start. A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. The VFD also has the capacity to control ramp-up and ramp-down of the motor during start or stop, respectively.
A VFD is comprised of three main components: A Rectifier, a DC link, and an Inverter. The rectifier converts the AC supply into DC power. The DC Link supports voltage through the drive from the rectifier and inverter, the DC link stores power converted by the rectifier. What is low voltage (LV) electricity? Low voltage (LV) electricity means electrical energy at voltages exceeding 32 Volt AC or 115 Volt DC, but not exceeding 1000 Volt AC or 1500 Volt DC for mines as per MSIR 1995.
A key function of low voltage switchgear is to provide electrical protection against thermal and mechanical stresses of short circuit currents. This is crucial in limiting the dangerous consequences of excessive currents and separating the defective current from the rest of the installation.
