|
Ripple frequency and Electrical Noise.
“Hunter Pacific
International’s” Notes on ripple noise.
RIPPLE CONTROL
Throughout Australia, but in particular Sydney and
other parts of NSW and Queensland, electricity distributors use a remote control
and switching system that is commonly called ripple control. Ripple control has
existed for many years and is used for controlling demand and implementing
different customer tariffs.
Our electricity supply is 240 Volts AC 50 Hertz. AC
means alternating current, a type of electrical energy that flows in one
direction for half a cycle, and then the opposite direction for the other half
cycle. 50 Hertz means there are fifty cycles per second. For electrical and
electronic products a cycle rate of 50 Hertz is very slow and therefore the
wires carrying the power can also carry other signals. Ripple control systems
superimpose signals on the 50 Hertz mains supply so they can be distributed
throughout a local power grid. Ripple control signals are used to switch on and
off high power consumption equipment such as water heaters and water supply
pumps.
Electrical equipment such as televisions, toasters,
fans, fluorescent and halogen lighting and some appliances may be sensitive to
ripple control signals. This results in an audible buzz being generated whenever
the signals are present. As different frequencies for these signals are used in
different areas, products may respond is some areas and not others. Some areas
have more than one ripple control system in operation and different signals may
be present at different times and affect different products.
WILL I BE
AFFECTED?
In areas that have ripple control installed for
off-peak tariff switching (such as off-peak hot water systems) there is usually
a dual tariff meter installed, or dual meters. A smaller control box marked “Zellweger”
may also be present. The meter or Zellweger box will usually have the ripple
control signal frequency marked on it (for example 1050 Hz). Even if you do not
have off-peak equipment installed your power supply may still be affected by
ripple control signals. Apart from looking for the control signal marking in
your meter box there is no way of knowing in advance if you will be affected by
ripple control signal noise.
WHAT CAN I DO IF I
AM AFFECTED?
There are ripple control signal filters available
for sale from experienced lighting and fan dealers. These filters have to be
installed by a licensed electrician and each filter has to be matched to the
particular signals in your area. Your dealer usually knows the signals used in
their local area and can recommend the correct filter.
It is not possible to build an electric motor based
product that rejects all the ripple control signals and the signals differ from
location to location. If you are affected by ripple control noise in your fan or
lighting product please contact your local dealer to purchase the appropriate
filter. The cost of the filter and the cost of installation are not covered by
the purchase price of the fan or light. Occasionally the ripple control signals
are so strong they cannot be sufficiently filtered.
WARRANTY CLAIMS:
Ripple control signal noise is not covered by
warranty. If you make a warranty based service call for ripple control noise,
you will be charged for the call-out by the electrician if he does
not find a genuine fault with the
product.
Contact A U Sparky on (07) 33 82 73 55. for
assistance.
We can supply and install Ripple Frequency Filters if required.
|