IRBT 60W Series Metal Clad Resistors

What are the IRBT 60W Metal Clad Resistors?

The IRBT is a 60W automotive-grade aluminium-housed wire wound metal clad resistor engineered specifically for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Its primary function is to control inrush current through Power Relay Assemblies (PRAs), safely limiting the surge current that flows when a high-voltage DC bus capacitor is pre-charged before the main contactor closes.

The IRBT's wide operating temperature range of –55°C to +155°C makes it suitable for the demanding thermal environments found in automotive drivetrains and underhood power electronics. Its resistance range of 1Ω to 1kΩ covers the typical pre-charge resistor values specified in EV battery management and BMS designs, with extended ohmic ranges also available on request.

The resistor has been tested to MIL-STD-202 methods for both vibration (10Hz–2000Hz) and mechanical shock (100g, 6ms sawtooth pulse), confirming the structural integrity required for automotive chassis applications. Its aluminium housing acts as a heatsink when bolted to a chassis surface, dissipating the brief but significant thermal load generated during each pre-charge cycle.

Pre-charge application note: In EV and HEV drivetrain architectures, the IRBT is placed in series with the main positive contactor. When the ignition cycle begins, current flows through the IRBT to charge the DC link capacitors to near battery voltage before the main contactor closes — eliminating the damaging inrush spike that would otherwise occur.

Model: IRBT
Resistor type: Metal clad resistor
Description: Automotive
Power Rating: 60W
Resistance (Ω): 1~1k
Tolerance (%): ±5, ±10
TCR (ppm/C): 260 Max.

Model: IRHC
Resistor type: Metal clad resistor
Description: Aluminum housed, chassis mounted
Power Rating: 40W, 60W, 100W
Resistance (Ω): 10~1k
Tolerance (%): ±5, ±10
TCR (ppm/C): 260 Max.

Model: IRB
Resistor type: Metal clad resistor
Description: Metal clad economy
Power Rating: 60W~120W
Resistance (Ω): 0.1~1.3k
Tolerance (%): ±2, ±5, ±10
TCR (ppm/C): 260 Max.

Model: SFH/SFV
Resistor type: Metal clad resistor
Description: Industrial
Power Rating: 60W~200W
Resistance (Ω): 0.1~2.2k
Tolerance (%): ±1, ±5, ±10
TCR (ppm/C):

Model: ARH, ARV
Resistor type: Metal clad resistor
Description: Automobile, pre-charge
Power Rating: 60W-500W
Resistance (Ω): 0.2~3k
Tolerance (%): ±0.5, ±1, ±2, ±5, ±10
TCR (ppm/C): 260 Max.