I have discovered that as your age increases, and you enter your senior
years, the discovery of how to do something becomes extraordinarily exciting.
In one’s youth the learning that confronted you at school and on through
college or university, if you were fortunate enough to climb the educational
ladder was a tedious affair.
You were confronted by either
teachers and lecturers you loved or hated. They gave termly tests and exams at
the years end which you dreaded, and then gave gleeful sighs of relief when you
learnt you had passed and achieved your goal.
In the age of the over-seventies, when ones appendages seem to be
breaking down, that gleeful sigh becomes an explosion of back-slapping delight.
I recently experienced such an explosion when I learnt how to wire a
three-position rotary switch, that’s one with an off position and two active
live positions. Such devices were common in the fifties, sixties and seventies
before the arrival of new chip and transistor technology.
They were in your HiFi units, your portable radios, your fridges, household
appliances, and your televisions. You used to switch channels, change
dishwasher and steam-iron temperatures, regulate toaster times and even set
your alarm clock using a basic rotary switch,
So, when a friendly defence-force trained plumber who I have worked with
for years, Keith, handed me a Metop three position rotary switch and asked me
to wire it so that he could run his grinder in a forward mode, a reverse mode
and an idle state, I was filled with a questioning mind, could I or couldn’t I
do it?
I started by exploring the internet and discovered numerous circuit diagrams,
several U-tube videos and one or two sites offering practical and theoretical
advice. I watched the videos, read the documents and perused the diagrams and
was none the wiser, until I remembered something I learn in my physics class at
school. Electricity is like watert it flows until something stops it and that’s
what a switch does!
How do you test the ability of electricity to flow?
You use a continuity tester and I have one.
So, I set to work testing the switch with it set in all three positions.
In the off position I discovered that there was no flow on any of the sixteen
terminals, eight one side of the barrel and eight on the other;
Position One, there was flow from one left mounted terminal to two
terminals on the right. I had discovered an on circuit. Two hours later, on
position two, and I had discovered the second on-circuit coming from a
different left mounted terminal to two right mounted terminals. Success!
But I was still confused, and something was not right. Yes, it worked, I
could feed live power in and out, but where the fuck did the neutral wire go?
I knew this system would work with Keith’s grinder, I could feed the live
current through the switch and connect a separate neutral to his grinder, but I
also knew that the Metop switch had not revealed all its secrets.
A phone call to another old friend, Herman the German, a trained and
fully qualified electrician of over forty years. He asked me to send a photo on
the “Whats Application”.
Another new learning experience for me. Having transported the photo
through the ether the cell phone rang.
“It’s got Bruken.” Said Herman.
“What? I don’t think it’s broken,” I replied.
“Not broken, it’s got Bruken!” he repeated irritably, across the
terminals, on both sides, what was it used on before?”
“I don’t know.” Then my O-level Deutsch resurfaced, “Ah, Bruken,
Bridges!”
“Ja, strip ‘em all off, they is confusing you They triangles.”
“Triangles?”
“Ja, them things mit three corners, strip the bridges, and then retest
with the continuity tester, you did gut mit dat!”
“I did that, and it works.”
“Ja, but you got no place for neutral, strip bridges and retest. Call me
back when you’ve done Dat.”
I duly followed Herman’s instructions and removed all the nine bridges
and discovered that I had no continuity at all between the terminals that I had
before!!
I felt as if I’d lost the battle, defeat was staring me in the face.
I re-read the numerous pages I’d downloaded from the Net and tried
Wikipedia. A triangle sprang into view and it all began to make sense!
Out with the tester and this time I knew what I was looking for, an
imaginary triangle with two of its corners touching two separate terminals, one
on the left side of the Metop and the other on the right.
Within half an hour I had discovered four circuits and had the Metop
switch wired up so that both positive and negative were switched on and off.
I quickly rigged up a light on an old piece of Oregon Pine, supplied
power to the Metop switch and onto the light and tested my wiring. It worked!
A gleeful telephone call to Herman-the-German, thanking him, followed.
And now, Keith’s grinder could now go forward or in reverse mode with a
flick of the rotary switch.
An explosion of back-slapping delight engulfed my aged old frame!
