Ron, Good point.
In my case the voltage measurements were made at the load terminals on the rear panel of the Samlex SEC-100BRM. Doug ----- Original Message ----- From: Ron Wright To: Repeater-Builder@yahoogroups.com Sent: Monday, October 22, 2007 5:12 AM Subject: Re: Re: [Repeater-Builder] Samlex Power Supplies One note on voltage drop. Where was the voltage being measured? It should be at the supply, not at the load. High currents will show drop due to IR losses at the load even with #10 or larger wire. I have a Samlex SEC1223. When I first got it I did some load test with 4 3 Ohm 100 W resistors in parallel. Know not at full load of 23 Amps (did not have enough resistors). There was essentially no change in output from no load to the instantious load of .75 Ohm (3 Ohm/4) at about 14 Amps. On my FT857, which I bought it for, I see little or no change in voltage even at 100 W CW key down (I use a J38 real CW man's key, hi). I have a number of the Astron RS20s and RS35s, some with and without meters (I like the meters). I like the supplies, but they are not good for what Astron says they will do. Have had problems in repeater service killing pass transistors under repeater conditions. I would never use the Astrons on anything that drew more than half the Astron Spec (AS35 never use for over 15-18 Amps in a repeater). For typical Ham use another issue. I do like Astron. The SEC1223 is 23 Amp continous although never tried for long term use. I like it due to its 3 lbs and my FT857 sets nicely on top. 73, ron, n9ee/r >From: "Bob M." <[EMAIL PROTECTED]> >Date: 2007/10/22 Mon AM 04:44:36 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Samlex Power Supplies > >Thanks, that does sound like the unit that my friend >is using. I wasn't sure what they did to sum the >outputs, and I didn't know it had BB capability. I'd >think the voltage drop would be somewhat constant once >some load current was drawn. > >My own repeater needs at least 14.0 Volts because I'm >using a 7812 regulator in front of the controller. I >was going to buy one of the new Samlex SEC-1235M units >and push the voltage up to 14.0, but if each one drops >that much under a partial load, I think I'm going to >stay with the RS35M instead, which exhibits nearly no >drop. > >Bob M. >====== >--- Doug Zastrow <[EMAIL PROTECTED]> wrote: > >> Bob, >> >> From the description of "five 20 A units in one box" >> it sounds identical to >> the Samlex SEC-100BRM as shown on the Samlex web >> site here: >> >> http://tinyurl.com/358l57 >> >> The manual for the SEC-100BRM can be found at the >> Samlex site here: >> >> http://tinyurl.com/3a7aa9 >> >> Page 20 of the manual shows: >> >> Two modules equpped: >> No load = 14.00 VDC >> Full load at 40 amps = 13.65 VDC >> >> Five modules equpped: >> No load = 14.00 VDC >> Full load at 100 amps = 13.35VDC >> >> >> All five modules feed a common bus. The bus is then >> fed to the load >> terminals through a Schottky diode for battery >> isolation purposes. >> >> In my personal tests with an SEC-100BRM equipped >> with two modules I saw >> no-load of 14.00 VDC. With a 7.5 amp load the >> output dropped to 13.89 VDC. >> Not nearly as heavy a load as your friend was >> seeing. >> >> My guess is the output dropping one full volt is >> suspicious. >> >> And as fair warning, I have discovered errors in >> Samlex documentation before >> so I approach their specs with a wary eye. >> >> Doug >> >> >> ----- Original Message ----- >> From: Bob M. >> To: repeater-builder@yahoogroups.com >> Sent: Sunday, October 21, 2007 4:24 PM >> Subject: [Repeater-Builder] Samlex Power Supplies >> >> >> Is anyone running a Samlex 12V supply in a situation >> where they can measure the voltage regulation from >> minimal load to something near half load? >> >> A friend has one of their 100A supplies (five 20A >> units in one box) and he's seeing about 1V drop with >> a >> 35A load (2M power amp), which is a bit more than >> I'd >> feel comfortable with. I don't know how they connect >> the supplies in parallel, so this could just be >> normal >> drop through the combining network, if any. >> >> I can't find any specs regarding this on the Samlex >> web site or in their manual for the SEC-1223. I >> would >> hope the supply can hold the voltage to well within >> 1%. >> >> For comparison, Astron RS35 supplies don't drop at >> all, or if they do, it's under 0.1V, just losses in >> the wiring. >> >> Thanks. >> >> Bob M. > >__________________________________________________ >Do You Yahoo!? >Tired of spam? Yahoo! Mail has the best spam protection around >http://mail.yahoo.com > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.488 / Virus Database: 269.15.3/1082 - Release Date: 10/20/2007 2:59 PM
