ELECTRICAL
RESISTORS
Standard
Resistor Brand™
For the past 25 years, KC Industries Pty Limited had owned and
operated Standard Resistor Company. During this period we have supplied
and designed resistors for most of the major lift and elevator companies.
We have played a role in designing resistors to replace expensive
and non-standard spare parts for various local rail authorities.
Standard Resistor Company™ has recently been integrated to
become a department of KC Industries.
The Standard Resistor brand name will continue to offer quality
and a wide range of wire and tape wound devices of proven reliability.
Rest assured that we can supply just about any need, from hobby
Slot Car resistors, to replacement parts for Scientific Instruments
or even Complex designs for Dynamic Braking applications.
As always, we remain geared to handle urgent delivery schedules,
offering a quality range of wire and ribbon wound power resistors
of proven reliability.
Variations
Coating
D Type
A non-brittle, impervious encapsulation based on the most recent
advances in silicone resins, with high-density ceramic filler providing
maximum insulation and heat transfer properties. Ratings for this
coating are shown for 250ºC, the normal commercial rating.
Resistors can be loaded to run above red heat with no risk of flammability
or permanent damage to coating other than a slight embrittlement.
The D coating is a smooth dull green finish and replaces previous
resinous varnish and brittle cement coatings.
V Type
Vitreous enamel coating provides the ultimate protection for resistance
elements. A high density (7+) borosilicate glass is fused on at
elevated temperature to provide an intimate bond between the winding
and a special steatite former, the entire system being carefully
matched to avoid thermal expansion differences. The very high thermal
mass and heat transfer rates provided by this coating, absorb heat
due to severe transient overloads. Continuous operation at 350ºC
is possible if designers wish to use smaller resistances for a given
load. This provides an alternate set of ratings to the normal commercial
250ºC rating as listed.
Adjustable
Resistors
Are provided in sizes from 20 watts upwards and feature an exposed
track of winding which is contacted by a clip carrying a silver
contact. The clip is positioned readily at any position along the
former.
Markings
Resistors are printed with permanent markings showing physical
size, wattage at 250ºC rating, type of terminal, resistance
value and tolerance.
Example: 8 H O A - D - 4
- 8 = PREFIX for Resistors
- H = Former diameter 1 1/8 inch
- O = Former length 10 ½ inch
- A = Adjustable
- D = Coating type
- 4 = Terminal type
Termination
Silver soldering of the resistance element to the terminal band
at a point remote from the terminal projection to avoid effects
of bending strains. This is the only proven reliable technique and
is used on Standard Resistor Brand product. Crimped, welded or soft
soldered, joints can lead to premature failure. Top grade resistance
alloys are used throughout and all coatings and ceramic components
are manufactured in our own plant, ensuring maximum uniformity and
quality.
Notes
- First letter relates to former diameter, actual wound diameter
is greater by varying amount due to wire size and coat thickness.
Second letter relates to length, which is constant.
- 2. First column gives normal commercial rating for a surface temperature
of 250ºC in 20ºC ambient. The second column ratings are
described on Page 1 under the heading V Coating.
- 3. The range of resistance are recommended limits other sizes may
be made but at increased cost and possibly reduced reliability.
- 4. Mounting Types AA and AB are self-supporting on radial wire leads
or solder lugs. The larger sizes can be supplied with horizontal
mounting feet. Vertical mounting with a through rod and dished washers
also available upon request.
- 5. Tolerances + 5% above 50 Ohms and + 10% below 50 Ohms are standard.
+ 1% available at increased cost.
- 6. Tapped Resistors can be supplied to detail.
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