
PFC for multiple small fan motors?
#1
Posted 29 October 2003 - 04:38 PM
I have a current project in my shop that is presenting a problem/concern. I have a bank of 56 (8 rows of 7 fans each) 120V, 60 Hzt, .2 A axial flow fans. (computer cooling fans 4-1/2" sq.) Each is individually wired to a terminal strip with 120V 15A coming in.
When I place my clamp on Amp meter I get a reading of like 21A @ start up and 13A at operation. This seems excessively high? My professor says it is due to my need of a Power Factor Correction capacitor(s)?
So is it possible for a novice to determine the correct PFC cap? I saw a program you can download? Any ideas and or constructive suggestions would be greatly appreciated!
CismontGuy
#2
Posted 29 October 2003 - 06:14 PM
Yes, if you correct he power factor, you will draw less current.
You will not necessarily see much impact on the start current though.
To determine the amount of power factor correction required, you need to determine the existing power factor or KW consumed. Once you have this figure, then you can easily calculate the pf required.
Best regards,
Mark Empson | administrator
Skype Contact = markempson | phone +64 274 363 067
LMPForum | Power Factor | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | Pressure Transducers | Smart Relay | GSM Control | Mark Empson Website | AuCom | Soft Starters
#3
Posted 30 October 2003 - 01:45 PM
Cismontguy
#4
Posted 30 October 2003 - 06:15 PM
To determin power factor, you can use a power factor meter or transducer, or you can measure the power consumption and current draw and caluclate the power factor from kw/kva, or you can measure the angle between the voltage and the current using an oscilloscope and calculate the power factor as Cos phi.
Best regards,
Mark Empson | administrator
Skype Contact = markempson | phone +64 274 363 067
LMPForum | Power Factor | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | Pressure Transducers | Smart Relay | GSM Control | Mark Empson Website | AuCom | Soft Starters
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