An Attic Adventure
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Once again, sufficient time was provided our churning mind to reach an
answer. It seems the world of
electronics has created some exciting things over the past 40 years.
One of them is a form of Silicon Controlled Rectifier known as a Triac.
When provided with a positive control voltage at it’s gate, it will
conduct AC power very happily until the gate signal is removed.
Then, it will continue to conduct until the current flow through it drops
to zero (which AC power does 120 times per second) - - at which point it shuts
off. This lead to the production of
neat little boxes called Solid State Switches (SSS) which take a tiny DC control
voltage and use it to switch massive amounts of power on the output end.
In this case I found an SSS which used a 4 – 32 volt (your choice) DC
control signal to switch up to 50 amps at 240 volts.
Nope - - I wasn’t going to need anywhere near that much, however, I
happen to like having lots of headroom in reserve, and dislike designs that push
the device
limits. This little box
has all sorts of neat things in it - - such as an optoisolator which prevents
the control signal from ever coming in contact with the massive power loads it
is switching ( 1 billion ohms isolation resistance ).
It also has a zero crossing detector which prevents inductive spiking at
turn-off. Hey - - for $20, you
can’t go wrong
With that out of the way, we rejoin our adventurer in the attic, having fortified
himself with gallons of iced
tea, he wrassled with a 250’ coil of 14/2 Romex
(which does NOT like to be uncoiled), straightening and snipping off a 90’
length to connect from the power panel to the SSS.
The video portion of this part of the story was lost in the swirling
attic heat, however the actions of our hero fighting the coils of the endless
Romex brings to mind images of 20 Keystone Cops packed into a Chrysler PT
Cruiser - - what I call the Chrysler Clown Car (not to be confused with a
Lincoln Town Car). Just as a word
to the wise - - you should unwind the Romex - - do NOT simply pull it from the
center of the coil. After two days,
the line had been run, from the garage, through Attic “A”, into the crawl
space of Attic “B”