DCAudioDIY.com

DC Area Audio DIYer's Community
It is currently March 28th, 2024, 10:45 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 35 posts ]  Go to page Previous  1, 2, 3, 4
Author Message
PostPosted: June 24th, 2021, 9:48 pm 
Offline
User avatar

Joined: January 15th, 2015, 7:19 am
Posts: 1697
Location: Baltimore MD
So is this a cap to ground at the primary of the power transformer


Top
 Profile  
 
PostPosted: June 25th, 2021, 9:16 am 
Offline
Site Admin
User avatar

Joined: February 28th, 2013, 10:38 am
Posts: 1682
Pelliott321 wrote:
So is this a cap to ground at the primary of the power transformer

? No image....

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.


Top
 Profile  
 
PostPosted: June 25th, 2021, 9:42 am 
Offline
User avatar

Joined: July 24th, 2015, 4:17 pm
Posts: 1701
Location: Parkville, Maryland
Pelliott321 wrote:
So is this a cap to ground at the primary of the power transformer

Power factor correction has nothing to do with the so-called DC component. Here is a link to a white paper that explains it better than I can:

https://electrical.theiet.org/media/168 ... on-pfc.pdf

_________________
Walt


Top
 Profile  
 
PostPosted: June 25th, 2021, 10:28 am 
Offline
User avatar

Joined: January 15th, 2015, 7:19 am
Posts: 1697
Location: Baltimore MD
I apologize for not being clear
we seem to be on a different topic now
David Bering mentioned that he includes PF circuit on his power amps.
I look this up and most PF correction seems to be a cap
I was just curious if David would elaborate


Top
 Profile  
 
PostPosted: June 27th, 2021, 2:18 pm 
Offline

Joined: March 2nd, 2013, 2:43 pm
Posts: 216
Location: Potomac, MD
The power factor issues that I deal with are not the degradation of power factor as a result of reactive loads but rather high harmonic distortion injected back into the mains when simple rectifiers are used in power supplies. This applies to most power supplies if corrective measures are not taken. For the removal of line harmonics, the current waveform needs to follow the voltage waveform, and thus the current waveform needs to be sinusoidal and in phase with the voltage waveform. The common approach, and the one I use, is an extra full-power processing circuit that uses a switching boost (PWM) topology that modulates the PWM in such a way as to cause the current to be drawn in such a way as to follow the mains voltage. Over the years there have been a number of integrated circuits for the controller; I use one of the newer ones sometimes referred to as a "one cycle" control, and provides for cycle-by-cycle current limiting.

Instead of rectifying the mains directly, the boost circuit converts the ac line into a regulated 375 volts dc, regardless of what the mains voltage is. This is why these circuits are often referred to as "universal mains" and thus do not require conversion between 120 and 240 volts for overseas operation. This 375 volts is not isolated from the mains, and so the PFC circuit needs to be followed by a second full power supply stage with a power transformer for isolation plus regulation if desired, which I do. This stage gives all of the required voltages for the amplifier, or whatever.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 35 posts ]  Go to page Previous  1, 2, 3, 4

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 44 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group