BE-5 - what do the controls on the BE-5 do? Selenium rectifier voltage drop

[Robert Groh]

I got a BE-5 schematic from the British web site (actually a GIF file that I modified to a jpg file and then printed on a letter sized paper) so we have that in hand (a pdf file would be very nice to have also). I'm going to puzzle out the schematic tonight but I would like to know the function of the 'taps' on the secondary as well as the role of the rotary switch. My Eico 'battery eliminator' has a 2 position voltage range switch and then a variable transformer setup to set the voltage.  Maybe the Heath has the same arrangement?  I.E.  the rotary switch is 'OFF - 6V - 12V' and the transformer has an adjustable secondary (limited voltage range)?

Regarding the voltage drop for a selenium voltage rectifier - I have had no luck in finding any numbers or spec's for them.  There is ample indication that the drop is considerably greater than a silicon diode (i.e. 3 or 4 volts for the high current low voltage type we are looking at here???).  Does anyone have any more precise data on these?

73
Bob, WA2CKY




________________________________
From: Paul Kraemer <elespe at lisco.com>
To: Robert Groh <rgroh at SWBELL.NET>
Sent: Monday, December 15, 2008 4:30:59 PM
Subject: Re: BE-5

Bob
I should have a schematic (pdf) tomorrow  to contribute to cause. Sorry no 
manual, just schematic.
Paul K0UYA
----- Original Message ----- 
From: "Robert Groh" <rgroh at SWBELL.NET>
To: <BOATANCHORS at LISTS.TEMPE.GOV>
Sent: Monday, December 15, 2008 9:09 AM
Subject: Re: BE-5


> To repeat what Jim said, if we (i.e. potential design sources) had ready 
> access to a BE-5 manual, we could probably give you some straight forward 
> ideas right off the bat.  But that (free access to Heathkit manuals) is 
> gone.  Drat.
>
> What you might do is make an electronic copy of the manual available (or 
> at least the important parts - schematic, circuit description and 
> specifications) so we can have a shot at it.  It is probably a very simple 
> change - just put either a big bridge rectifier package in there or simply 
> 4 big silicon diodes.  Purely guessing here but I would think you probably 
> need diodes with 25A capability and 50 V reverse voltage capability. I 
> believe selenium rectifiers have a higher forward voltage drop.  I'll take 
> a quick look at Mouser for parts and the web for diode data and get back 
> to you.
>
> 73
> Bob Groh, WA2CKY
>
>
>
>
> ________________________________
> From: Bob Moulton <rmoulton at EMAIL.ARIZONA.EDU>
> To: BOATANCHORS at LISTS.TEMPE.GOV
> Sent: Monday, December 15, 2008 12:24:05 AM
> Subject: [BOATANCHORS-TEMPE] BE-5
>
> I am finally getting around to fixing up a Heathkit BE-5 Battery 
> Eliminator that
> I bought a number of years ago. Given recent events, it's also fortunate 
> that I
> found an original copy of the manual at the same time. I once saw a site 
> that
> had a rewire of this unit using a bridge rectifier to replace the original
> selenium rectifiers. Unfortunately, this was bookmarked on the last 
> computer
> and the bookmarks didn't make the transfer. Anyone know of this site or 
> have an
> idea of how this was done?
>
> Thanks
>
> Bob
>
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