RES-IS Datasheet, PDF (1/2 Pages) Ohmite Mfg. Co. – Pulse handling capability

IS Series
Ultra Low Profile Power Resistors
F e at u r e s
• Heatsinkable
• Low profile
• High power
• Rugged construction
• Ultra low profile thick-
film on steel
• Pulse handling capability • 175W to 270W sizes
• Non-flammable
• Low inductances
• Single fixing heatsink
mountable
• Available with fast-on terminals or wire leads
uses
• Braking resistors
• In-rush current limiter
• Bleeder resistor
• Power switching
• Soft charging
S ERIE S S P ECI F ICATI O N S
Power Resistance
Rating Range
Type (watts) (Ω)
Tolerance
IS175 175 5Ω to 10KΩ 10%, 20%
IS200 200 5Ω to 10KΩ 10%, 20%
IS250 250 5Ω to 10KΩ 10%, 20%
IS270 270 5Ω to 10KΩ 10%, 20%
Construction
Dielectric ^Termination
Glass Overcoat
Resistive Glaze
Stainless Steel
characteristics
TCR <250ppm (surface temp less than 150°C)
Maximum element 365°C
temperature
Working voltage Not to exceed 300V
Over-voltage rating 5X rated power for up to for up to 1 second
Resistive element Film
Derating element surface temp. at 100% to 0% power
at 200°C surface temp.
Power rating dependent on mounting and heatsink ther-
mal capacity
Hot spot surface 200°C max.
temperature
Pulsed load at full Max. 1%ΔR; (see Fig 1)
pulse power rating Mounted on a 0.06°C/W heatsink with
1,000 cycles forced air cooling, air temperature 25°C (ref
AH32430 12" long)
Solder Silver solder is recommended for IS Series
resistors. Leaching of the silver in the termi-
nation will occur if non-silver solder is used.
60/40 tin-lead solders are not recommended
for use with the IS Series product.
Screw torque 3.5 Nm
Derating
120
100
80
60
40
20
00
50 100 150 200 250
Resistor Surface Temp., oC
THIS PRODUCT IS
DESIGNED FOR USE WITH
PROPER HEATSINKING.
Maximum base plate temperature of
the resistor must be monitored and
kept within specified limits to estab-
lish the power rating. Best technique
is to attach a thermocouple to the
side of the base plate of the resistor.
136
1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax [phone] • www.ohmite.com • [e-mail]
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