[GreenKeys] Teletype REC11 Rectifier "is NOT suitable for use in the signaling ... circuits of Teletype apparartus"

[Paul Birkel]

Got out the scale; "beefy" to the tune of exactly 39 pounds, oh my ...

-----Original Message-----
From: Paul Birkel [mailto:pbirkel at gmail.com] 
Sent: Monday, November 20, 2017 7:34 AM
To: greenkeys at mailman.qth.net
Subject: RE: [GreenKeys] Teletype REC11 Rectifier "is NOT suitable for use
in the signaling ... circuits of Teletype apparartus"

Thanks to everyone for your observations.  I didn't interpret the
pub-wording to be inclusive-OR, and can certainly imagine that using the
REC11 for both purposes might be a bad idea.  I read it as exclusive-OR and
didn't see any reason for excluding its (alternative) use on signaling
lines.

I remember selenium rectifiers from disassembling TVs in my youth, but don't
recall ever seeing such large stacks.  Yes, I guess I should replace those,
and mount the originals for "viewing pleasure"!

The choke is the biggest that I've ever encountered; a monster!  And the
transformer is a real beast.  Both look like they ought to easily handle
many Amps (need to check the AWG on the windings).  Total weighs more than
20 pounds.  I guess those old selenium rectifiers were pretty low-current,
and thus the limiting factor.  Whether a larger smoothing capacitor is
needed seems unlikely given the massive choke, however increasing the MFD is
an easy task.  And the electrolytic capacitor may have gone dry, lo these
many decades.

OTOH, I also have the Army Signal Corps AN/FGQ-2 Perforator that it was used
to power, and a wide table designed for it, so I really should keep the
REC11 in a form that it can be alternatively employed in that capacity --
replacing the bridge and smoothing capacitor won't hurt that at all :->.

Does anyone have the manual for the AN/FGQ-2 Perforator?

Finally, on the REC11 does the 10 uF (oil-filled) capacitor across the
series-winding on the input side result in a resonant circuit intended to
provide a degree of resistance to voltage sags or surges?  What is that
configuration called in the literature?  I've had no luck deducing it in my
stabs-in-the-dark :-<.

-----Original Message-----
From: Jim Haynes [mailto:jhhaynes at earthlink.net] 
Sent: Saturday, November 18, 2017 2:55 PM
To: Paul Birkel
Cc: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Teletype REC11 Rectifier "is NOT suitable for use
in the signaling ... circuits of Teletype apparartus"

I'm not sure about the REC-11.  I know some Model 19 tables are wired to 
use the same rectifier for running the punch and for loop supply.  My 
guess is that the output voltage of that particular model might vary too 
much during punching to be satisfactory for a loop supply.  It might be
satisfactory for a local test loop but not for a situation where online
signal quality is not so good.  Maybe you could pout an oscilloscope on
the output and see how much the voltage varies as tapes are being punched.
Or connect a voltmeter to the output and hold the punch magnet contacts
closed and see how much the voltage drops.  But you probably should not
hold them closed very long since they are not meant to be run that way.