[ICanHas]

That particular VFD did not have PFC. In fact, it was a 480V VFD being run off a voltage doubler since he managed to get a 480V condensing unit (and the VFD to run it) for super cheap.

All you've got is anecdotal evidence. The measured current could very well be incorrect if it was not measured correctly using a right instrument.

Please provide the kVA, kW, THD and 3rd, 5th, 7th, 9th and 11th harmonic percentages.
It's not the high VA to kW ratio per se that's the problem. It's the harmonic content, especially the 3rd harmonic that affects power quality to other customers as well as disproportionately higher losses in transformers.

Did you advocate the dirty power drawing diode-capacitor front-end and convince him to do ti?

Thank you ~

Originally Posted by mejunkhound

as for :
cost involved in the process of forcing the offending customer to pay the expense of putting his neighbor on a separate transformer or getting a court order to disconnect the harmonic load or install filtration device.

Would be very interested if you can provide even a SINGLE case law reference to this ever happening at a residential DIY level....

The first industrial case law IIRC is that Colorado Springs disconnected a certain Mr. N. Tesla from their grid when he shut down the system with an inordinate overload - maybe one could call N. Tesla a DIY, sure we would all be complimented.

As far as DIY folks 'polluting' the grid, what a crock - there are so few DIY that use multi HP non PFC VFD that it is a teaspoon in the ocean.

One install would not affect it at feeder level. It would affect it at the nearest PCC or causing enough localized pollution to affect delivered power quality to neighbors. What's your ground for calling it "what a crock"? 3kW 6kVA >100% THD is easily over 10% of demand on subdivision transformer.

From the IEEE draft:

"Employing electronically-commutated motors (ECMs), the input of a variable speed heat pump resembles a large switch-mode power supply (e.g., 3 kW or more). The ECM is a dc brushless motor with stator construction similar to a three-phase ac induction motor. The stator winding current is sequenced and switched creating a rotating magnetic field. This switching is performed electronically by an inverter. The rotor uses permanent magnet construction.
Conventional heat pumps have a current THD of 13% with around 9% third harmonic content; some of the newer ECM designs have current THD values of 123% with the third harmonic content of 85%.
Because of the large load, there is concern that it would only take relatively few installations of this type of heat pump to cause voltage distortion problems. In [2], the authors found the voltage distortion on a distribution feeder reached 10% when the penetration rate for these variable-speed drives reached 10%, i.e., when 10% of the homes installed the new ECM designs. Though a 10% THDV would be deemed unacceptable by most of us, it does give us a sense of how much of a particular nonlinear load would cause problems on a residential feeder.

[2] International Standard IEC 1000-4-7, “Electromagnetic Compatibility (EMC), Part 4: Testing and Measurement Techniques”.