Power factor correction

Has anyone installed, or considered installing a power factor correction device to your power system?

It’s typically used in industrial settings for improving power efficiency of inductive loads like motors. I read the EU requires PFC for devices that consume over 75 watts.

Besides making the grid more efficient, I wonder if and/or what kind of benefit or problems they might pose to our audio systems.

I was hoping Ted would reply so we all can learn

A lot of power factor correctors use similar technology to switching power supplies, they may inject high frequency noise into a system.


Are they good for the power company by improving ‘efficiency’? I’m not privy to how the EU makes decisions like requiring PFC >75w but they seem to make more sustainable regulations vs. USA

From the little I’ve read it appears the need for power factor correction has come about largely because of switching power supplies…? I would think large inductive loads like motors are the antithesis…?

My cursory reading reveals the most prominent form of PFC are banks of capacitors in parallel to the load that brings the devices Power Factor as close to 1 as possible.

Advanced forms of this have power monitoring that enables a controller to vary the number of capacitors connected as PF varies.

It sounds like it’s the controlling and monitoring systems that is introducing HF noise. Perhaps the types of capacitors used as well?

You only need large (switched) capacitor banks to offset large motors (and sort of vice versa.)
The power factor issues from relatively pure inductive (motors) loads don’t affect audio equipment much, they can lower the instantaneous power available, but most homes don’t have big enough motors to be a problem.
The power factor problems from un-power factor corrected switching supplies can cause annoying noise in audio systems. But the supplies in, say, computers are mostly power factor corrected (but by switching power supply technology, so there’s still some noise.)

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Our vacuum cleaner has the biggest motor but it is hardly ever used… Not much other things with motors that connect to mains… At least not that I can find… :rofl: :rofl: :rofl:

A spin dryer has a pretty hefty motor. Back in the day I used to switch one on and off when connected to the same circuit as an amp in order to view on a scope how well the power supply coped with it.