Friday, August 31, 2007

Highly Isolated Power Source

Have you ever had a need for an isolated power source floating at high voltage? If you’ve ever considered a battery, but then quickly rejected that thought because you would need to replace it periodically, here’s a technique that doesn’t require wires, transformer or any other traditional approach.

Advanced Cerametrics has introduced Extreme Life Span Micro Power Supplies that harvest energy from ambient sources of vibration energy to power wireless sensors and other devices…forever. It uses piezoelectrics to generate electricity. For more information see You can also build your own, using piezoelectric materials.


Thursday, August 30, 2007

HV Circuit Breaker rated up to 3150 Amps

The Sion vacuum circuit-breaker from Siemens is designed for use in
all common types of medium-voltage switchgear. A complete series of
models is available for rated voltages from 7.2 kV to 24 kV with a
short-circuit breaking current of up to 40 kA and rated currents up to 3150 A

Thanks to the ingenious use of insulating material, this
air-insulated circuit-breaker allows a much narrower construction
than is otherwise usual with air-insulated designs of
circuit-breaker. This makes smaller widths and depths possible than
with fully insulated circuit-breaker versions. The special partition
shell construction of the insulation materials also provides
mechanical support for the switching element.

Wednesday, August 29, 2007

High Voltage in Jet Pack

PFS has received a patent on jet pack (without the jets) using ion
electronic backpack for human flight with silent, vertical takeoff & landing.

In simple terms, the base technology uses the flow of ions from one
electrode to another to move air which is pushed when these ions
collide in an air medium. Electrons driven across an air-gap create a
flow in that media when they collide with particulates in the air,
resulting in thrust directionally opposite to the master cathode.

Normally ion collision begins at around 20,000 volts, a figure that
PFS hopes to reduce, In this high voltage region, a gain of 1 watt's
worth of thrust can be achieved by doubling the voltage. However, 2
watts of input power are expended to achieve one watt of ion process.
The proposed studies will focus further up the efficiency curve to a
region where new gains can be achieved.

For information, see

Tuesday, August 28, 2007

New High Voltage Pulse Generator Has 2.5ns Rise Time

SDS (Systems Development & Solutions) based in France has introduced high voltage pulse generators based on the use of field-effect transistor technology. These compact GIPO generators can produce pulses that can reach 5.5kV with a rise time of around 2.5ns. The pulse length is adjustable from 200ns down to 30µs. The model GIPO is available either in a block configuration or as a stand-alone unit.

It is basically composed of an adjustable high voltage dc/dc converter and a high speed, high voltage switch. The specifications include a brief theory of operation.

These high voltage pulse generators can be used in several applications where it is necessary to switch high voltage quickly. The GIPO series can be used with:
o Pockel Cells
o Multi Channels Plates
o Intensified CCDs
o Laser Diodes
o Flash Lamps

For more information, see

More on DC high voltage transmission

The use of DC avoids phase shift issues. AC current is limited to roughly 1000 miles in air, and about 5-10% of that in under water transmission (because of due to dielectric effects). Another phase problem with AC are transmission line effects, where it is possible to have twice the voltage due to reflection.

Another problem with AC is skin effect, which is roughly a quarter of an inch. Thus, DC transmission is a more efficient use of the conductor cross section.

Sunday, August 26, 2007

IEEE Safety Standard

IEEE 510:1983—IEEE-recommended practices for safety in high-voltage and high-power testing; Reaffirmed: 1992. Administratively withdrawn, however, you may still find the information worthwhile. Some existing IEEE standards still reference this one.

One place you can purchase this standard is at

Friday, August 24, 2007

Power Utilities Protective Relay Usage

According to the North American Study of Electric Power Utilities Protection and Control Management and Staff, roughly half of relays installed are digital relays instead of electromechanical types. However, almost all new relay purchases will be digital.

The most common communication protocol is RS-232, however, RS-485 and RS-422 usage is increasing.

It also appears that IEC 61850 will be adopted by many utilities in the near future.

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Thursday, August 23, 2007

High Voltage Cocktail

Time for another diversion:

1.5 fl. oz. of Scotch Whisky
1.0 fl. oz. of Triple Sec or Cointreau
1.0 fl. oz. of Lime Juice
Soda Water

Combine all ingredients (except Soda Water) in a cocktail shaker with the ice, shake, strain into a tumbler filled with ice, top with Soda Water, stir.


Monday, August 20, 2007

High Voltage Current Regulators

IXYS has an interesting family of high voltage current
regulators. Rated up to 450V, they can also be used in high voltage
power supplies, as an overvoltage suppressor or for soft start circuits.

Friday, August 17, 2007

New range of high-voltage high-capacitance surface-mount chip capacitors

A new range of high-voltage high-capacitance surface-mount chip capacitors has been introduced by Syfer Technology. These high-voltage capacitors span the range from 16V to 6kV, with capacitance ranges from 0.47pF to 15uF, and are available in both C0G and X7R dielectrics.

Be sure to check our article, High Voltage Capacitor Notes, especially if you plan on using the X7R type.

Wednesday, August 15, 2007

Field strength and breakdown voltage

30kV/cm is the normal field gradient or strength (at breakdown) in
uniform fields for small gaps on the order of 1cm under normal
conditions of temperature and pressure. For large gaps of several
meters this can reduce down to 6kV/cm (reference J R Lucas).
Paschen's curve I think is where the 30kV/cm is pulled from. Note
that the curve itself is for 1cm spacing at 1 atmosphere and 25 deg C
for conductors of an infinite plane, parallel, and perfectly smooth.

Tuesday, August 14, 2007

New HV Surge Resistors

It's often difficult to find high voltage resistors rated for surge applications. Arcs can occur inadvertently in many applications, thus, requiring surge limiting resistors. Other applications have designated periodic rapid discharges.

Stackpole Electronics has announced a significant expansion to their ASR and SPR series of axial leaded anti-surge resistors. The ASR series adds a ¼ watt body size to the current sizes of 1 watt, mini ½ watt, and mini ¼ watt sizes. The SPR series has significantly improved the maximum working voltage up to 2000 volts, the max. overload voltage up to 3000 volts, and the surge withstanding voltage up to 10KV. The ASR and SPR series are a power metal film technology and are really the same part. The SPR series is only for the 1 watt and mini ½ watt sizes and strictly the values from 1 Meg ohms to 12 Meg ohms that are UL 1676 recognized. The ASR series is available in resistance values down to 100 ohms and up to 33 Meg ohms and can withstand surges from 1 kV up to 10 kV depending on size and resistance value. Together they offer an excellent alternative for carbon composition and ceramic composition resistors for pulse power withstanding with low inductance. In fact, side by side testing shows the ASR/SPR series is superior to carbon comps for high voltage surges.

For more information about Stackpole products, contact Stackpole Electronics, Inc. at 919-850-9500 or email


Monday, August 13, 2007

Technique improves voltage breakdown characteristics

Vishay has introduced a surface-mount multi layer ceramic chip capacitor that has average voltage breakdown twice that of standard commercial-grade products. They call the approach HVArc Guard® . It's a patent pending technology that essentially increases the effective creepage distance along the part's surface. Voltage breakdowns are twice that of some competitor
products. Sounds pretty interesting!

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Friday, August 10, 2007

High Voltage Propulsion

In the quest for human electronic flight, one approach is using
electrically charged, polarized, proprietary alloys to create
thrust. The flow of ions from one electrode to another moves air
which is pushed when these ions collide in an air medium. Electrons
driven across an air-gap create a flow in that media when they
collide with particulates in the air, resulting in thrust
directionally opposite to the master cathode.

The voltage applied to two electrodes must be high enough to create
the ion process conduction current needed to begin the propulsion
process. Normally ion collision begins at around 20,000 volts. For
more information on this unusual high voltage application, see

Thursday, August 9, 2007

Plexiglass in high voltage applications

It's not unusual for someone to select Plexiglass (tm) or other
acrylics for use in high voltage applications such as a high voltage
power supply. It does, after all have a good dielectric strength
rating. Plus it is inexpensive and it is transparent, which can come
in very handy in some systems. However, there are better choices,
primarily because Plexiglass is flammable, and brittle. In addition,
cracks can occur due to stressing or due to exposure of the vapors of
some solvents. I've heard of Plexiglass catching on fire in high
voltage power supplies.

A good material to consider instead would be Lexan (tm). There are
other possibilities, as well, but Lexan is a good place to start.

Wednesday, August 8, 2007

Self Biased Optical Isolator

From time to time we come across interesting products in the high
voltage area. We'll include a brief description in this high voltage
blog as we find such products.

The first item in this series is a Clare optically isolated driver
which has 3750Vrms of input-to-output isolation, and requires no
external power supply on the secondary (output) side.

The CPC1580 is an optically isolated MOSFET gate-driver integrated
circuit. The application of sufficient input LED current (2.5 to
10mA) in the CPC1580 activates the internal load-side driver
circuit. The CPC1580 uses photovoltaic cells to collect the optical
energy generated by the LED.

Tuesday, August 7, 2007

Apex Microtechnology sold

Apex Microtechnology, a designer and manufacturer
of high performance monolithic IC and hybrid
high voltage amplifiers has been acquired by Cirrus Logic Inc.

Cirrus Logic intends to continue marketing the
Apex hybrid products under the Apex precision
Power™ brand and supporting Apex's approximately
80 products and 1,200 customers worldwide.

Monday, August 6, 2007

Your High Voltage Story

We are publishing your stories, comments or impressions of high
voltage. Tell us about design challenges, interesting applications,
shocks, problems, or solutions that relate to high voltage
electricity. We will gather and publish them.

Please email us at with your story. Please
use "High Voltage Story" as the subject.

We reserve the right to edit all submissions, and all appropriate
legalese apply.

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Sunday, August 5, 2007

DC High Voltage Transmission Lines

Yes, DC.

Construction began in early 2007 on the world's first 800kV DC power
transmission lines. They are located in China. Currently, there are
HVDC transmission lines in Italy (200kV), the US (called the Pacific
DC Intertie, from the Pacific Northwest to Los Angeles), Brazil
(600kV) and elsewhere.

DC transmission lines have lower losses than comparable AC
lines. Also, the transmission lines themselves cost less than for
AC. Thus, they are preferable in cases where power generating
stations are far from population centers. Such conditions exist for
large hydroelectric plants in Brazil, India and China.

HVDC converter stations use thyristors to convert the generated power
from AC to DC, and vice versa.

Thursday, August 2, 2007

High Voltage Glossary

The High Voltage glossary at provides definitions for
such terms as corona, dielectric withstanding voltage and creepage
distance. Other terms with particular meanings for high voltage
applications include:

FLASHOVER (A disruptive discharge of electricity through an
insulator, normally characterized by a voltage drop. Also, a
discharge around or over a liquid or solid material. This can be a
single event, intermittent or continuous. Same as Arc)

TRACKING (Marks made on a surface that experienced flashover)

CORONA INCEPTION VOLTAGE: The lowest voltage at which continuous
corona of specified pulse amplitude occurs as the applied voltage is
gradually increased.