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Variable speed motors11/4
I'm researching putting a VFD on my dust collector.
It seems that we want 4000 FPM or so in the ducts, but what happens if you have a 10HP system with only one 4" or 6" vent open? Obviously 4000 FPM in that branch will not be 4000 FPM in the main 12" duct and keeping 4000 FPM in the main duct with a small opening doesn't seem like it'll save any power.
Or am I just concerned about the negative pressure at the fan inlet regardless of velocity?
Am I missing something?
I can't see the advantage of a VFD on a dust collector. Won't you be constantly changed speeds if you bring on or drop off multiple heavy chip generators?
I question the economy of using a VFD. They are not cheap and a 10 hp motor uses minimal power. If it was 200hp it might be worth engineering a system with sensors to monitor the velocity in the ducts.
I did some math a while back and determined a 15hp collector costs $12 a day to run single shift. Let's say 10hp is $8 a day. That's $2000 a year. How much can you save? You need a system to control the vfd. An interesting thought but probably not worth the effort.
You need to leave a minimal amount of gates open for the system to maintain velocity. We run our system wide open.
Soft start on newer collector vfd with a paroid sensor as gates open and close Will need some help programming the vfd.
The soft start will help on the demand charge, bearings, fan and duct work
cabinetmaker - what kind of sensor?
see Dwyer Instruments
I talked to a VFD supplier and he determined that we would be better off with a soft start on the 10hp collector unless we run it for 12 hour shifts
Even a soft start is overkill. Just put a standard contactor.
Just open second small gate up stream of the gate you are using.