FRS Series 

FUSIBLE RESISTORS
  • Flame retardant Silicone coated
In order to meet the growing demand worldwide for resistors to fuse or blow as a safety measure, HTR can provide fusible resistors which fuse or blow if they are subjected to an abnormal spike of voltage / current.

Physical configuration
FLAME RETARDANT SILICONE COATED TYPE -please refer to HTR type H1 to H10

Electrical and Environmental Characterstics/Data

 
Test Performance
Resistance tolerance ± 10% [K]: ± 5% [J] 
[ < 1ohms ± 0.05 ohms]
Di-electric withstanding voltage Max DR ± [ 2% ± 0.05 ohms]
Insulation resistance >1000 M [ Dry]
Temperature co-efficient ± 550 ppm/°C
Short time overload Max D R ± [2%+ 0.05 ohms]
Moisture resistance Max D R ± [5%+ 0.05 ohms]
Load life Max D R ± [5%+ 0.05 ohms]
Ambient operating temperature range -25 °C to + 155° C
Flame test Specifications laid down by UL have been met satisfactorily
NOTE:
Contrary to popular belief, fusible resistors are not standard resistor types and each type of fusible resistor must be tailor designed to suit a particular application.
 
 
ORDERING INFORMATION:
In order that we can design a fusible resistor suitable to your needs, we need the following data from you:-
  • Power rating in terms of watts.
  • Resistance in ohms.
  • Tolerance.
  • Maximum continuous working voltage across the resistor, at which the resistor must continue to function.
  • Fusing voltage - The voltage at which the resistor must fuse or blow.
  • Fusing time - The duration within which the resistor must fuse or blow, on being subjected to the fusing voltage.
  • In case, lead preforming is required, we need a drawing. This service is provided, upon a minimum order of 5000 pieces.

    • These resistors can also be provided in taped form.

NOTE :
Generally speaking as per international standards, a fusible resistor fuses on being given fusing voltage from instantaneously to 45 seconds without any flame.

At HTR if no special data is provided, we assume that if a fusible resistor is ordered, it should fuse on being given voltage calculated at 16 times power from instantaneously to 45 seconds.

Precautions to be taken : Before conducting this test the voltage must be correctly set / adjusted by first using a dummy piece which should then be discarded.
 

TYPICAL APPLICATIONS
As mentioned previously a fusible resistor is a tailor made dual purpose component -
    (a) In normal conditions it functions as a resistor.
    (b) In high overload conditions it acts as a fuse/safety device.
 

Eurocap International Limited.   138 High Street,  Cheshunt,  Herts,  EN8 0AP  England.
Tel    +44 (0)1992 625407      Fax   +44 (0)1992 625420
Email eurocap@dial.pipex.com