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ELECTRONICS
AND DEMAND MANAGEMENT BY POWER UTILITIES
*** NOTICE:
DUE TO HIGH DEMAND FOR THE CONTENT, THIS WEBSITE SHALL BE MOVED
TO DEDICATED HOSTING RATHER THAN THE RESIDENTIAL BROADBAND IT IS
CURRENTLY HOSTED ON. PLEASE CONTINUE TO E-MAIL ME FOR
SUPPORT/INFORMATION. IN THE MEANTIME THE SITE WILL BE MOVED TO A
HOSTING PROVIDER, ETA 15 JUNE 2009. THANK YOU ***
Ripple Control
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Q:
What is "ripple control"
A: Ripple control is a means whereby the local
power authorities are able to temporarily turn
off large electrical loads in peoples' homes to
limit the impact of peak demand for electricity.
The local council is usually
subject to steep rates for peak demand (peak
means higher than usual) by ESKOM. Therefore in
peak periods, such as when people get home from
work to cook food, the local council will send commands to
turn off the largest load in the home- the
water heater or "geyser" to reduce
peak demand for electricity. |
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Then
when peak demand subsides, normal operation is
restored. |
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An
example of a modern ripple receiver installed in
homes. |
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My interest to this
was drawn when in 1993 we moved into a different
area. I noticed the house was fitted with a
Zellweger Uster receiver circa 1975. I opened it
to discover it was an electromechanical device
with passive components and a resonant circuit
that was tuned to 1050Hz. A very large paper
capacitor and a very unusual ferrite transformer
design on a base PC board to detect the tone and
generate a signal upon its reception. The tone
would start the mechanical timer, which was then
held running by a latch contact. When the timer
went past 360 degrees, the contact dropped out
and the timer stopped (the transmission was also
complete at this point) The pulse pattern
incoming would then be matched upon output of
this mechanical timer and if a match was
detected it would activate the change-over relay
contact, also a mechanical toggle design with a
bakelite flag. The mechanical timer had a
ratchet and pawl on a dial, the dial could be
turned to select a number. I found out later
they were channel numbers, 22 in all.
I very soon realized that other stuff is also
being controlled this way and were on a
different channel because, without fail, each
time the streetlights came on, a transmission
was always in progress (audible as 1kHz |
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buzz
in sympathy with the data on the line which I
could hear when the streetlights came on). This
audible buzz was also, and still is, a nuisance
factor on audio equipment. Sensitive unbalanced
audio inputs pick the signalling up easily. |
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Electromechanical
receiver type ZE-22 circa 1971 installed in almost all
homes in Roodepoort, Johannesburg, and Pretoria.
Made by Zellweger Uster (now Enermet). |
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A WORD OF WARNING TO THOSE WHO HAVE THE BLACK
RECEIVER SHOWN ABOVE AND ARE CONTEPLATING
DISASSEMBLING IT OR OPENING IT...
The ZE-22 receiver (shown above) is classified
as
NUCLEAR WASTE. The equipment contains a
glass tube, that contains a pellet
composed of radium and thorium. DO NOT CRACK OR
BREAK the glass glow tube within. The function
of this component is to limit the output of the
ripple transformer, which, under certain
conditions could reach insanely high voltages,
the glow tube thus acts as a VS valve to protect
the solenoid winding (remember, this receiver
was made in a time when tubes (valves) were
still being used in consumer electronics)
I DO NOT
accept any responsibility for your failure to
heed this warning!!!
Neither ESKOM or anyone else I know is aware of
this little fact, and considering that ESKOM has
mandated ripple receiver installations in ALL
homes in SA, I presume this means replacement of
the old with new.
See http://en.wikipedia.org/wiki/Zellweger_off-peak
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