General Note

IRC reserves the right to make changes in product specification without notice or liability.

All information is subject to IRC’s own data and is considered accurate at time of going to print.

A subsidiary of

TT electronics plc

• 4222 South Staples Street • Corpus Christi Texas 78411 USA

Wire and Film Technologies Division

Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com

SPH/SPF Series

General Purpose Failsafe

Molded Wirewound Resistor

Electrical Data

IRC Type

SPH

SPF

EIA RS-344 Style

CRU2

CRU2

MIL-R-11 Style

RC32/RC42

RC32/RC42

Resistance - Std.

0.1

Ω to 2400Ω

0.1

Ω to 1000Ω

Tolerance - Std.

±5%, ±10%

±5%, ±10%

Power Rating

2 watt @ 70°C

1 watt @ 115°C

Derating to 0 @ 160°C

2 watt @ 70°C

1 watt @ 115°C

Derating to 0 @ 160°C

Max. Continuous Working Voltage

Min. Insulation

Resistance

10,000 Meg

100 Meg

10,000 Meg

100 Meg

Min. Dielectric

ATM

Withstanding Volts

(RMS)

Reduced Pressure

1000V

625V

1000V

625V

Hotspot Temperature Rise

145°C @ 2 watts

145°C @ 2 watts

Typical Load Life

5%

5%

Current Noise

Negligible

Negligible

Dry

Wet

1. Resistive Element

All resistor types have resistance alloy

winding on a braided fiberglass substrate.

Intermediate silicone coatings are used

to enhance processibility and to provide

protection to the resistive element.

2. Termination

The SPH and SPF resistors are terminated

using an alloy coated copper flashed steel

lead welded to a cap of the same material.

This termination assembly is mechanically

crimped, utilizing an improved crimp design,

to the resistive element.

3. Encapsulation

The SPH and the SPF are encapsulated uti-

lizing a compression molded phenolic plastic

material. The SPF has a flame resistance

coating applied over the resistive element

to provide flammability protection when

destructive overloads may occur.

4. Marking

All products are marked utilizing heat and

solvent resistant color code bands consistent

with EIA/MIL requirements. The first band

is double width to designate wirewound

construction. A fifth band, blue in color, is

used for flameproof identification.

1

3

4

2

(See notes below)

SPH/SPF Series Issue December 2008 Sheet 1 of 3