vfd power factor
vfd power factor
(OP)
We design exercise equipment, some using DC drives and some using AC drives. They are in-house designs. The AC drive is a simple V/F type and exhibits poor PF (0.7 or less) owing to its front-end being a simple bridge rectifier and capacitor design. The supply is 240V 60Hz single-phase. The output is 3-phase 230VAC 10 to 120Hz. The motor is 2hp.
To improve the PF we can add a series inductance either on the AC or DC side of the bridge, but inductors are large and expensive. We could design our own PFC, or we could specify a commercial VFD that has PFC.
Can anyone recommend VFDs of 2 to 3hp that feature PFC?
thanks
To improve the PF we can add a series inductance either on the AC or DC side of the bridge, but inductors are large and expensive. We could design our own PFC, or we could specify a commercial VFD that has PFC.
Can anyone recommend VFDs of 2 to 3hp that feature PFC?
thanks





RE: vfd power factor
With internal dc link reactors, typical PWM drive power factor should be 0.9 - 0.95.
RE: vfd power factor
But what is your purpose for wanting to improve the pf? If is because of pf penalties, residential users (in the US anyway) don't get penalized for poor pf, so there is no compelling reason to exert effort to correct it. In addition, VFDs have a poor distortion power factor, but the displacement power factor, which is usually the only kind measured by standard utility metering, is actually around .95.
If you are needing to do this because you want to go for an Energy Star rating, I'm not sure the .95pf requirements for SMPS apply to VFDs.
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RE: vfd power factor
Right now we measure PF using a California Instruments AC programmable supply, I believe it is summing both flavours of PF. Drives that have no active PFC exhibit poor PF on the California box.
I was curious to know if any commercial drives had built-in active PFC.
I had one large maker of drives tell me that their PF was 0.95- but that must have been based on displacement only.
Energy Star is a possibility- not sure if it applies to our products.
RE: vfd power factor
We ended up (in our typically tangential manner) discussing this in greater detail this thread, probably worth a read for you. thread237-244890: Using VFD as a phase convertor to run 3 phase pumps
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RE: vfd power factor