Published: 14 April 2014
Category: Q&A
Eddie asks this question about an electric motor, variable speed drive and associated power factor correction equipment. It has been answered by ABB (Theme – Electrical Control):
This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question: An electrical installation has a variable speed drive (VSD) located in the switchboard room. The driven electric motor itself is located about 150m away in the associated factory.
What are the advantages and/or disadvantages of fitting a power factor (PF) capacitor adjacent to the motor?
Answer: We do not recommend the installation of power factor capacitors on the output side of a variable speed drive for two reasons:
1) The power factor equipment will be shielded from the mains network by the drive and so no adjustment of the power factor will be seen by the mains network.
2). VSDs do not like to supply capacitive loads.
We therefore suggest that the power factor correction equipment be located close to the power source.
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