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Total 731 documents matching your query.

241. Re: [Amps] Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 31 May 2010 13:15:08 -0700
Hi Vic, It's perfectly OK to hang a small load across half of a center-tapped primary. "Small" is in comparison to the primary current. Ten Tec does this for the fan in their 425 amp. The only thing
/archives//html/Amps/2010-06/msg00015.html (7,890 bytes)

242. Re: [Amps] Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 01 Jun 2010 11:32:59 -0700
Nothing wrong with that, if you're rich, BUT 1.5A at 13.5 volts is only 20 watts, which is 170mA at 120V. Double that for two tubes. Nothing to worry about on a transformer that's rated to supply 2-3
/archives//html/Amps/2010-06/msg00027.html (9,210 bytes)

243. Re: [Amps] Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 01 Jun 2010 11:36:02 -0700
Your licensed master electrican was WRONG. It is entirely legal, and entirely proper from an engineering point of view to place a 120V load across half of a center tapped transformer as long as that
/archives//html/Amps/2010-06/msg00028.html (8,913 bytes)

244. Re: [Amps] Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 02 Jun 2010 11:32:58 -0700
There isn't any. The center tap of a 240V transformer in a residential power distribution system IS grounded. The center tap of a 240V transformer inside equipment is NOT grounded, and MUST NOT be gr
/archives//html/Amps/2010-06/msg00034.html (9,285 bytes)

245. Re: [Amps] FW: Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 03 Jun 2010 14:36:11 -0700
You understand correctly, Bill. First, it is important to understand the difference between LOAD equipment and DISTRIBUTION equipment. Both of the electricians commenting on (or quoted) in this threa
/archives//html/Amps/2010-06/msg00047.html (10,008 bytes)

246. Re: [Amps] FW: Bridging 120v loads across HV primary windings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 04 Jun 2010 10:46:27 -0700
No, it's simply one of many possible situations that the NEC is written to protect against. If I had time, and it was worth the effort, I could cite MANY examples of people being killed by unsafe ins
/archives//html/Amps/2010-06/msg00051.html (8,255 bytes)

247. Re: [Amps] winding toroids (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 30 Jul 2010 14:15:07 -0700
Nope. Solid and stranded are electrically equivalent. 73, Jim K9YC _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/a
/archives//html/Amps/2010-07/msg00359.html (7,171 bytes)

248. Re: [Amps] More parasitic choke questions (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 31 Jul 2010 09:31:31 -0700
And perhaps some misunderstandings as well. There is no such thing as a pure inductance. EVERY real inductor has stray R and C. EVERY real inductor has a self resonance. EVERY real inductor has loss.
/archives//html/Amps/2010-07/msg00394.html (11,057 bytes)

249. Re: [Amps] Why no images allowed? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 14 Aug 2010 23:48:14 -0700
When I need to do that, I put the image on my website as a pdf and post a link in the email. Of course, not everyone has a website. :) Another very good reason for no attachments is that some folks a
/archives//html/Amps/2010-08/msg00209.html (8,878 bytes)

250. Re: [Amps] Holes vs. screen for chassis ventilation? (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Wed, 06 Oct 2010 10:04:14 -0700
There is a detailed set of relatively simple design equations for the relationship between hole size and RF leakage vs frequency in all versions of Henry Ott's excellent texts on EMC. I'm working wit
/archives//html/Amps/2010-10/msg00058.html (8,956 bytes)

251. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Mon, 25 Oct 2010 10:06:53 -0700
Both of these references are way off base. I strongly suggest that you study my RFI tutorial, paying careful attention to the discussion of "the pin 1 problem" and the discussion of ferrite chokes. I
/archives//html/Amps/2010-10/msg00365.html (8,014 bytes)

252. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Mon, 25 Oct 2010 23:49:59 -0700
Study http://audiosystemsgroup.com/RFI-Ham.pdf 73, Jim K9YC _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2010-10/msg00374.html (8,025 bytes)

253. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Tue, 26 Oct 2010 09:47:55 -0700
Nope. Most consumer and semi-pro audio and video products, and virtually ALL ham and computer products have pin 1 problems at every audio input and output. The good news is that most PRO audio mfrs h
/archives//html/Amps/2010-10/msg00379.html (8,835 bytes)

254. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Tue, 26 Oct 2010 09:58:16 -0700
Study my tutorial, previously cited. There are good uses for #43 if it is used properly (that is, with a sufficient number of turns to match the operating frequency). One of the great virtues of Fair
/archives//html/Amps/2010-10/msg00381.html (10,274 bytes)

255. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Tue, 26 Oct 2010 18:02:17 -0700
Mixes (and the numbers that describe them) are generally proprietary to their manufacturer. Mixes #31, #43, #44, #61, #67, #73, #75, #77, and upstate NY. It was originally a family owned company -- h
/archives//html/Amps/2010-10/msg00394.html (11,351 bytes)

256. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Tue, 26 Oct 2010 20:24:01 -0700
Colin, Yes, you're right. I meant to say that would NOT trust a reseller to have a clue about the use of their products.. Thanks! 73, Jim K9YC _______________________________________________ Amps mai
/archives//html/Amps/2010-10/msg00395.html (9,887 bytes)

257. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Wed, 27 Oct 2010 00:59:59 -0700
One of the traditions in this world is that when you discover or invent something something you get to name it. Neil Muncy discovered the Pin 1 Problem and published it, and that's what he chose to c
/archives//html/Amps/2010-10/msg00400.html (9,559 bytes)

258. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Wed, 27 Oct 2010 01:12:30 -0700
There is nothing magic about rack mounted gear that makes it more professional, nor makes if free of pin 1 problems. When Neil Muncy published his landmark paper exposing the Pin 1 Problem in 1994, v
/archives//html/Amps/2010-10/msg00403.html (11,775 bytes)

259. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Wed, 27 Oct 2010 10:17:15 -0700
On the show floor, it is often easy to spot them with a visual inspection. What you're looking for is a shield connection that goes directly to the shielding enclosure. If it does NOT, but goes to th
/archives//html/Amps/2010-10/msg00415.html (11,841 bytes)

260. Re: [Amps] construct ferrite "line isolator" (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Wed, 27 Oct 2010 10:26:33 -0700
Yes. BUT -- when distributors talk about "good" it's sometimes hard to know what "good" means to THEM. Are they talking about use as inductors or as suppressors? And what Ward has said here ties in w
/archives//html/Amps/2010-10/msg00416.html (10,045 bytes)


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