hb001 CVT introduction the perfect sine wave

hb001 CVT introduction the perfect sine wave
hb001 CVT introduction the perfect sine wave
Outstanding Spike and Electrical Noise protection:
The very best power protection
comes from a special type of
transformer known as a
Constant Voltage Transformer
(CVT). Providing unparalleled
reliability and conditioning
performance, spikes and
electrical noise are neutralised
with attenuation as high as
75dB.
In addition the input (or primary)
and output (or secondary)
transformer windings are
physically separated. Known as
Galvanic isolation this
separation ensures that there is
no direct connection between
the mains supply and load.
A CVT therefore provides an
impenetrable barrier to spikes
and high frequency electrical
noise. This barrier also works in
reverse mode to prevent a
'noisy' load from polluting the
mains supply itself.
How does it work?
Although simple in concept the CVT is very difficult to explain, leading to some electronics experts
to describe it as magic. Effectively the aim is to keep the Iron core of the secondary saturated,
which keeps the voltage on the output winding constant.
The primary winding needs to be unsaturated to prevent unacceptably high losses.
This effect is achieved in two ways.
Firstly the two Magnetic Circuits are separated but inter-linked allowing the transfer of energy from
Primary to Secondary.
Secondly the secondary circuit has a deliberate inductance introduced and is connected to a
resonating capacitor. This LC circuit is tuned to resonate at the desired transformer frequency.
The consequence is that the secondary part of the transformer runs saturated and the output
voltage is constant.
Superior Sag, Surge and Brownout protection:
Mains voltage sags and surges are automatically corrected by a CVT.
When faced with an extreme surge voltage such as a local lightning strike the power conditioner
will present a low impedance to the mains to protect both itself and any connected loads.
Automatic Sine-wave generation:
Using ferro resonant transformer technology means that each power conditioner will always
generate a pure stable sine-wave even when fed from a polluted mains or square-wave supply.
Advance Electronics Limited. Advance Park, Wrexham. LL14 3YR United Kingdom
Sales: 01978 821 000 Fax: 01978 810 852 Accounts: 01978 821 149 Web: www.aelgroup.co.uk
Registered in England and Wales 1742090. An AEL Group Company
A = INPUT
B=
OUTPUT
NO moving parts NO electronics
ONLY magnetic magic
Perfect Switched Mode Power Supply (SMPS) driver:
Ferro resonant transformer technology provides waveform shoulder-lifting - the CVT is the kindest
way to drive a switched mode power supply. Input surges are reduced prolonging life and
conduction times are lengthened. In addition the CVT provides harmonic buffering and improved
reservoir capacitor hold up for the inevitable supply micro breaks which occur with grid protection
switching.
Constant Voltage Transformers don't care about the ambient
Unlike some sensitive electronic stabilisers a CVT works in a very large range of conditions.
Standard units can work at permanent temperatures of 40 deg C with 50 deg C not a problem for
short periods, alternately a special design can cope with 70 deg C. CVT's will operate at minus 40
deg C although the heat generated by their operation means the transformer is soon warm to the
touch.
Overload protection
The CVT is designed to supply an overload of 150% at around 200% overload the output
waveform collpases to near 0V, WITH NO HARM TO THE CVT, direct short circuiting for long
periods of time is not a problem for the CVT, as soon as the short is removed it will carry on
supplying useable power.
Oscilloscope hold-up picture
ride-through picture
Something for nothing: so long as at least 30% of the normal supply voltage is present the suitably
selected CVT can provide adequate power for your critical load.
Advance Electronics Limited. Advance Park, Wrexham. LL14 3YR United Kingdom
Sales: 01978 821 000 Fax: 01978 810 852 Accounts: 01978 821 149 Web: www.aelgroup.co.uk
Registered in England and Wales 1742090. An AEL Group Company
Common mode noise attenuation Series mode noise attenuation
Regulation
The output stays within 5% from zero to full load, if a tighter regulation is required trade-offs can be
made. At 50% load the regulation is about 3%. Between zero to light loading (3%) is the greatest
drop in output, so a permanent light load improves the regulation further. A Full to Zero load event
may cause a momentary variation of 8% but the CVT settles in a couple of cycles.
Output within 5% for zero to full load
Outstanding output regulation at low loads or
high input voltages
Advance Electronics Limited. Advance Park, Wrexham. LL14 3YR United Kingdom
Sales: 01978 821 000 Fax: 01978 810 852 Accounts: 01978 821 149 Web: www.aelgroup.co.uk
Registered in England and Wales 1742090. An AEL Group Company
Stabilisation
The output stays within 3% for an input swing of 15% at half load 3% output can be achieved for an
input swing of approximately 30%
Output within 3% for nominal input +/-15% Even
wider input swings at below nominal loads
Regulation outside of specification
The combined stability and regulation is 8% again improvements can be made by reducing the
loading
Output within 8% for zero to full load and nominal
input +/-20%
Power Factor
All units present a power factor to the supply
which varies with output load.
The CVT will drive a wide range of power factor
loads (+/-0.75)
Small changes in the output voltage will be found
in comparison to the setting with a resisitive load.
Advance Electronics Limited. Advance Park, Wrexham. LL14 3YR United Kingdom
Sales: 01978 821 000 Fax: 01978 810 852 Accounts: 01978 821 149 Web: www.aelgroup.co.uk
Registered in England and Wales 1742090. An AEL Group Company
Output changes with frequency of input
A 1% frequency change produces a 1.5% change in output voltage
Phase shift
There is a smal phase shift across the CVT
varying with load
part of the AEL technical handbook return to hb000 Handbook Index
Advance Electronics Limited. Advance Park, Wrexham. LL14 3YR United Kingdom
Sales: 01978 821 000 Fax: 01978 810 852 Accounts: 01978 821 149 Web: www.aelgroup.co.uk
Registered in England and Wales 1742090. An AEL Group Company
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