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Resistors
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Interworld manufactures a complete line
of custom engineered and designed High Voltage Non Inductive Impulse Resistors.
In general our resistors are designed for applications where high voltage, low
inductance and good heat dissipation is required. Applications include Lightning
Research for the generation of lightning and switching waveforms, Insulator Testing,
Transformer Testing, Front (series) resistors, tail (parallel) resistors, charging
and earthing resistors, measuring resistors for resistive impulse voltage dividers.
Other uses include resistors for Impulse Current Shunts, Damped Capacitive Voltage
Dividers as well as for recurrent surge generators etc. Interworld started manufacturing
resistors in August 1979 and to date have outfitted some of the largest High Voltage
Laboratories worldwide.
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- High Withstand voltage for lightning
and switching impulse voltages up to 400kV
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- low inductance (Inductive time
constant L/R=5-250 nsec, depending on ohmic value; in most cases below
75nsec)-High thermal load capacity up to 60kJ
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- low resistance variations through
wide range of operating temperature long term resistance
stability
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- small resistance tolerances -
standard 4%; on request 3%, 2% or 1%
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- terminals according to customer
requirements (mild steel, brass, copper - chromium, cadmium or silver
electroplated )
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- ohmic values: 12 ohms - 150 kilo
ohms
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- custom made with deliveries within
weeks.
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resistors are anti-inductively wire
wound on insulation core of high thermal resistance.
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resistance wire is enamel insulated,
of nickel-Chromium 80.20% composition, with temperature coefficient of
100ppm/degree C.
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Winding is initially vacuum sealed in
resin. For lower impulse loads it is protected with fiberglass tape and heat
shrink sleeve. In most cases it is cast in resin of high thermal
conductivity and high operating temperature.
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Shape, overall dimensions and
terminals of resistors are according to customer
specifications.
Interworld have designed a custom spring loaded terminal which
allows for very fast replacement of our High Voltage Non Inductive
resistors.
View images and more details here.
In order to design and quote your
resistor, the following information is required:
- application of resistor
(waveshaping, charging, measuring etc.)
- resistance value and desired
tolerance
- operating voltage
- energy (impulse load) in kJ, impulse
repetition rate and duty cycle
- operating medium (air, gas, oil)
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overall dimensions and limitations and details of terminals (Diagrams are
required)
Upon receipt of the above information, a
preliminary design of the resistor is prepared, which will be submitted for
comments and final approval.
The following
companies have purchased our resistors and continue
to rely on Interworld
for High Quality non inductive resistors:
B.C. Hydro - Powertech Laboratories
- Canada
Ontario Hydro - Canada
Hydro
Quebec - IREQ - Canada
Haefely Trench - Canada
Asea Brown Boveri, U.S.A.
Westinghouse - U.S.A.
Canadian
Standards Assosciation - Canada
Messwandlerbau - Germany
General
Electric - U.S.A.
Bonneville Power - U.S.A.
Olex Cables -
Australia
Oak Ridge National Laboratory
Tyree Westinghouse -
Australia
and many more.
Other products
produced by Interworld Instruments include:
Current Shunts, Voltage
Dividers as well as the capability to Retrofit existing or outdated
Dividers.
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