Flameproof Power Resistors PW Series
PW series wire wound resistors are available in four power ratings of 5, 10, 20 and 50 Watts. They are designated Types PW5, PW 10, PW20 and PW 50. Combining a unique design with a
high degree of automatic assembly, they offer practical possibilities for cost saving.
PW Series wire wound resistors are particularly recommended for the following situations:
(a) A low cost, easily installed power resistor is required e.g. dish washers, electric
stoves, range hoods etc.
(b) Circuits requiring an actual wattage dissipation equal to, or less than, the wattage rating of the PW resistor selected.
(c) Operation must be reliable at high ambient temperatures.
(d) Radio, TV or industrial circuits requiring the PW wattage dissipation and where a fireproof resistor is essential.
(e) Medium power bridge circuits with well balanced pairs.
(f) Medium power attenuator networks.
Design and Construction
The resistance wire is uniformly and tightly wound on a glass fibre core. Types PW5 and 10 have alloy plated copper leads securely fastened to the winding by special
terminations, while the PW20 and PW50 have 6.3 QC terminals.
The resistance winding is housed in a rectangular ceramic case which is filled with an inert and non-flammable compound, unaffected by solvents. Having
high thermal conductivity, this filling compound maintains a lower surface temperature.