[ARC5] [BoatAnchors] Smart People: Multi-Set Current Corn-fusion

[Donald Davis]

What is your voltage doing during this event?  There are 2 common types of
current control for power supplies:  Current Limit where the current will
remain constant to the current set at the start of use,  and Current
fold-back where the current set will cause the output to drop to zero and
may / may not automatically reset after the short is removed.

73 de don ad6pb

-----Original Message-----
From: BoatAnchors [mailto:boatanchors-bounces at theporch.com] On Behalf Of
David Stinson via BoatAnchors
Sent: Sunday, December 03, 2017 6:09 AM
To: ARC-5 <arc5 at mailman.qth.net>; milsurplus at mailman.qth.net
Subject: [BoatAnchors] Smart People: Multi-Set Current Corn-fusion

Dear People Smarter Than Me:

I'm confused.  Bumped-up the RAX "burn-in" to 100V
B+, which is provided to all three receivers from
the same buss, using a current-limited supply so if any of the old parts
decides to "shuffle off this mortal coil," the supply will shut that down.
Did some current measurements with all sets in the same operating mode:

All sets connected and off:  13 mA, within 1 mA of expected.
LF set playing alone: 30 mA (has fewer stages than the others).
LoHF set playing alone: 41 mA.
HiHF set playing alone: 46 mA (about 10% "hot,"
will check).
but:
All three playing normally at once: 83 mA.

Ummm... shouldn't that be like 117 mA?

Anybody got an idea?

73 OM DE Dave AB5S