Document Number: 30201

For technical questions, contact: ww2bresistors@vishay.com

www.vishay.com

Revision: 11-Jul-07

157

RH, NH

Wirewound Resistors, Military, MIL-PRF-18546 Qualified,

Type RE, Aluminum Housed, Chassis Mount

Vishay Dale

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: For RH-5 through RH-50 size terminal

finish - Tin/lead is 60/40 Sn/Pb w/Nickel underplate and

Lead (Pb)-free is Ni/Pd/Au, finish is on copper clad steel core

terminal. For RH-100 and RH-250 terminals are threaded

stainless steel.

Note:

Military (RE) parts are only available with tin/lead 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:

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 min at - 55 °C

± (0.5 % + 0.05

Ω) ΔR

Short Time Overload

5 x rated power for 5 s

± (0.5 % + 0.05

Ω) ΔR

Dielectric Withstanding

Voltage

± (0.2 % + 0.05

Ω) ΔR

Temperature

250 °C for 2 h

± (0.5 % + 0.05

Ω) ΔR

Moisture Resistance

MIL-STD-202 Method 106, 7b not applicable

± (1.0 % + 0.05

Ω) ΔR

Shock, Specified Pulse

MIL-STD-202 Method 213, 100 g's for 6 ms, 10 shocks

± (0.2 % + 0.05

Ω) ΔR

Vibration, High Frequency

Frequency varied 10 to 2000 Hz, 20 g peak, 2 directions 6 h each

± (0.2 % + 0.05

Ω) ΔR

Load Life

1000 h at rated power, + 25 °C, 1.5 h “ON”, 0.5 h “OFF”

± (1.0 % + 0.05

Ω) ΔR

Terminal Strength

30 s, 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

± (0.2 % + 0.05

Ω) ΔR