Aluminum-Housed Resistors (CAR)
These resistors are categorized within the lower power ratings among aluminum-housed types. They find primary application in DC-link circuits for both charging and discharging, as well as in compact inverter drive systems where they function as brake resistors. CAR resistors feature an aluminum casing equipped with cooling fins, significantly augmenting their surface area. This design facilitates swifter cooldown times, thereby reducing power cycle durations.
The choice of aluminum for the housing material stems from its corrosion resistance, non-magnetic properties, lightweight yet robust nature, and excellent heat conductivity. These resistors are fully insulated and devoid of any exposed live components.
Their nominal power output spans from 105 to 410 watts when relying on natural air convection cooling. For higher power requirements, forced air cooling can be employed. Their working voltage aligns with UL standards at 600VAC/850VDC and IEC standards at 690VAC/975VDC. The standard ingress protection rating stands at IP50, with the option for IP54/65 available upon request. These resistors come equipped with 300mm-long high-temperature cables. Custom cable lengths are also available, selected based on Ohm values and nominal power ratings and typically range from AWG 16 to AWG 14.
The overload capacity depends on the resistor’s Ohm value and physical size, typically spanning from 5 to 15 times the nominal power rating over a 5-second period. Additionally, an optional thermal switch can be integrated to provide overtemperature signaling when necessary.