Ac /dc Choke
Posted 06 May 2008 - 01:33 PM
what is the need for input and output chokes in variable speed drives
any criterial for choosing these
Posted 06 May 2008 - 07:05 PM
Input chokes add a reactive impedance to the supply as seen by the VFD and thereby limit any peak currents. This has the effect of reducing the potential for damage when there are transients on the supply, plus reducing the harmonic content of the current drawn from the supply, plus it helps to balance up the currents on the three phases.
Output chokes limit the rate of rise of current on the output and reduce the losses in the VFD when there is a high capacitance (long cables) on the output of the VFD.
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