[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: www.drsstc.com- power factors

Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>

>Your PF is unity??

Well the DRSSTC contains a whole bunch of different resonant circuits and
they all have their own power factors etc. But in answer to the question I
think you're asking-

The H-bridge is delivering a sine wave of HF current into the primary, that
(if the coil is properly tuned) is exactly in phase with the H-bridge output
voltage. So the displacement power factor as seen by the H-bridge is indeed
1. If you like, you can think of this as being a result of the tank
capacitor "power factor correcting" the inductive load presented by the

You can also calculate another power factor, as (real power delivered to secondary/reactive power circulating in primary) which seems to come out about equal to the coupling, ie from 0.1 to 0.3. This is of interest when working out what rating of tank capacitor you need for a given coil. But bear in mind that Antonio's theory suggests a lower tank cap rating than mine.

note- In the OLTC, these two power factors were both about 0.15 which led to
inefficient use of silicon.

Finally there is the power factor of the 50/60Hz current drawn by the DRSSTC from the wall socket, which (like any rectifier load) seems to be around 0.6 without a PFC coil, to 0.8 with.

Steve C.