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125
RH, NH
Vishay Dale
Document Number 30201
Revision 09-Sep-04
For technical questions, contact ww2bresistors@vishay.com
Wirewound Resistors, Military, MIL-PRF-18546 Qualified,
Type RE, Aluminum Housed, Chassis Mount
MATERIAL SPECIFICATIONS
Element: Copper-nickel alloy or nickel-chrome alloy,
depending on resistance value
Core: Ceramic, steatite or alumina, depending on physical
size
Encapsulant: Silicone molded construction
Housing: Aluminum with hard anodic coating
End Caps: Stainless steel
Standard Terminals: 100% Sn, w/Nickel underplate, or 60/
40 Sn/Pb, w/Nickel underplate, coated Copperweld® on RH-5
through RH-50 size. Threaded stainless steel terminals on
RH-100 and RH-250.
NOTE: Military (RE) parts are only available with 60/40 Sn/Pb
finish.
Part Marking: DALE, Model, Wattage, Value, Tolerance,
Date Code
NH NON-INDUCTIVE
Models of equivalent physical and electrical specifications are
available with non-inductive (Aryton-Perry) winding. They are
identified by substituting the letter N for R in the model
number (NH-5, for example).
SPECIAL MODIFICATIONS
A number of special modifications to the aluminum housed
resistor style are available upon request. Special
modifications include:
• Terminal configurations and materials
• Resistance values and tolerances
• Low resistance temperature coefficient (RTC)
• Housing configuration
• Threaded mounting holes
• Preconditioning and other additional testing
APPLICABLE MIL SPECIFICATIONS
MIL-PRF-18546 is the military specification covering
aluminum housed, chassis mount, power resistors. VISHAY
RH and NH resistors are listed as qualified on the
MIL-PRF-18546 QPL.
PERFORMANCE
TEST CONDITIONS OF TEST TEST LIMITS
Thermal Shock Rated power applied until thermally stable, then a minimum of 15 minutes at - 55°C± (0.5% + 0.05Ω) ∆R
Short Time Overload 5 x rated power for 5 seconds ± (0.5% + 0.05Ω) ∆R
1000Vrms for RH-5, RH-10 and RH-25; 2000Vrms for RH-50
4500Vrms for RH-100 and RH-250; duration one minute
Temperature 250°C for 2 hours ± (0.5% + 0.05Ω) ∆R
Moisture Resistance MIL-STD-202 Method 106, 7b not applicable ± (1.0% + 0.05Ω) ∆R
Shock, Specified Pulse MIL-STD-202 Method 213, 100g's for 6 miliseconds, 10 shocks ± (0.2% + 0.05Ω) ∆R
Vibration, High Frequency Frequency varied 10 to 2000Hz, 20g peak, 2 directions 6 hours each ± (0.2% + 0.05Ω) ∆R
Load Life 1000 hours at rated power, + 25°C, 1.5 hours “ON”, 0.5 hours “OFF” ± (1.0% + 0.05Ω) ∆R
30 second, 5 pound pull test for RH-5 and RH-10, 10 pound pull test for other
sizes, torque test - 24 pound inch for RH-100 and 32 pound inch for RH-250
Dielectric Withstanding Voltage ± (0.2% + 0.05Ω) ∆R
Terminal Strength ± (0.2% + 0.05Ω) ∆R