Flat-pack: Features, Applications and Available Families
A flat-pack is a type of high-power resistor designed for industrial applications where compact size, efficient heat dissipation, and easy mechanical integration are required. Thanks to its structural configuration and metal enclosure, it represents an ideal solution for braking resistors, pre-charge resistors, and capacitor discharge resistors.
Within the power resistor landscape, the flat-pack stands out for its application versatility and for the wide range of construction options available, including different protection ratings and additional features such as integrated thermostats or UL marking.
What Is a Flat-pack and Why Choose a Metal Enclosure
The flat-pack belongs to the category of metal-housed resistors, a practical and robust solution for industrial applications. The metal structure ensures effective heat dissipation while providing mechanical protection, making it suitable for environments where reliability and durability are essential.
The availability of various IP protection ratings allows installation in both low-stress indoor environments and more demanding climatic conditions. Optional configurations, including thermostat integration, fuses, or specific mounting solutions, further expand its range of applications.
RFX Flat-pack: Compact Solution for Standard Applications
The RFX family consists of a wire-wound resistor on a mica plate coated with cement, enclosed in a galvanized steel housing with IP20 protection. This configuration makes the RFX flat-pack suitable for standard applications where high sealing levels are not required.
It is also available in a thermal switch version (RFXT) and with UL marking. An anti-inductive winding version can be supplied upon request for specific applications.
RFK and RFD Flat-pack: Enhanced Protection for Harsh Environments
For more demanding applications, the RFK and RFD families provide a wire-wound resistor on a mica plate, immersed in quartz sand and enclosed in an anodized aluminum housing.
The RFK is sealed with an aluminum cap and silicone elastomer, while the RFD version uses silicone elastomer sealing to ensure IP54 protection. RFK 600 and 800 models are particularly suitable for railway applications and can reach IP65 protection. Variants with thermal switches, 45° cut housings for easier installation, and UL-marked versions are also available.
Flat-pack with Finned Heat Sink: RDF, RFZ and RFZ/C
The RDF, RFZ and RFZ/C families feature an aluminum heat sink with a spiral wire winding inserted into a perforated ceramic tube filled with quartz sand. Sealing with dielectric cement or silicone elastomer ensures a minimum IP54 protection rating.
These flat-pack are particularly suitable when enhanced thermal dissipation is required while maintaining compact size and enclosure protection. Versions with integrated thermal switches (RDFT, RFZT/C) provide additional temperature monitoring and control.
Heavy-Duty Flat-pack: RFH, RFP and RCH
The RFH, RFP and RCH families further expand the application range of the flat-pack in a metal enclosure.
The RFH integrates a finned heat sink filled with quartz sand and can reach protection levels up to IP65. The RFP is available in vertical or horizontal configurations, with optional integrated thermostat and fuse. The RCH, enclosed in a stainless-steel tube, is designed for high-temperature and particularly demanding environments, offering mechanical robustness and IP65 enclosure protection.
When to Use a Flat-pack
A flat-pack is recommended in all applications where high power must be managed in limited space while ensuring efficient heat dissipation and mechanical protection. It is an ideal solution for braking systems, pre-charge resistors, capacitor discharge resistors, and more generally for industrial applications where reliability, thermal stability, and long service life are critical requirements.
With nine different families available, it is possible to select the most suitable configuration based on power requirements, protection rating, installation environment, and applicable standards.
Contact us for a technical consultation: the team at Fairfild will help you select the most suitable flat-pack for your application, ensuring reliable performance and long-term operational continuity.
