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Pf Not Be Unity |
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 Oct 14 2009, 10:32 PM
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#1
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Junior Member  Group: Members Posts: 3 Joined: 14-October 09 Member No.: 6,830  |
Hi all,
I have a very small quistion: Why it's not prefered to make the PF equals unity. That's all thanks |
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Oct 15 2009, 05:14 AM
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#2
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Senior Member Group: Full Member Posts: 301 Joined: 21-October 06 Member No.: 2,159 |
QUOTE (toubar @ Oct 15 2009, 03:32 AM)  Hi all, I have a very small quistion f33 : Why it's not prefered to make the PF equals unity. That's all thanks Hello, Welcome to the forum. This question has been asked many times and eng given their answers. I would suggest to "Search" this topic in this forum and you would find many topics. Best Regards -------------------- "Don't assume any thing, always check/ask and clear yourself".
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Oct 15 2009, 05:42 PM
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#3
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Posting Freak Group: Moderator Posts: 2,383 Joined: 24-April 02 From: Christchurch, New Zealand Member No.: 1 |
Hello toubar
Welcome to the forum. There are two major types of displacement power factor correction, static correction and bulk correction. It is imperative that with static correction, you do not correct to unity because at unity, the inductive reactance of the load is equal to the capacitive reactance of the capacitors and this means the circuit is at resonance at the supply frequency. If the supply becomes disconnected and the capacitor(s) remains connected to the motor terminals, there will be a high voltage generated that will cause major damage. see http://www.LMPhotonics.com/pwrfact.htm With bulk correction, this is not a problem, but it is difficult to maintain unity exactly. The normal standard is to be better than 0.95 and this is much easier to achieve and there is very little loss relative to unity. Best regards, Mark. -------------------- Mark Empson administrator
Skype Contact = markempson | phone +64 274 363 067 LMPForum | LMP Tech Warehouse | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | LMP Software | Mark Empson Website |
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Oct 16 2009, 12:52 PM
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#4
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Junior Member Group: Members Posts: 3 Joined: 14-October 09 Member No.: 6,830 |
thanks alot for your concern and for the helpfull inforation
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Oct 16 2009, 01:01 PM
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#5
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Junior Member Group: Members Posts: 3 Joined: 14-October 09 Member No.: 6,830 |
I'm sorry butihave another quistion in the same topic
what is the advantage from using both bulk and static PFC at the time in the same factory if it's a duplicated quistion please refer to the place of the answer thanks, toubar |
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