FWR Series Fusible Wirewound Resistors
Resistive wire wound on a ceramic core with insulated resin coating
Power ratings: 1W, 2W, 3W and 5W
Resistance range: 0.1Ω to 200Ω
Tolerance: ±5%
TCR: ±300ppm/°C
Operating temperature range: −55°C to +200°C
Dielectric withstanding voltage: AC 500V for 1 minute
Short-time overload: 5× rated power for 5 seconds
Designed to fuse safely under abnormal overload or fault conditions
RoHS compliant; supplied in axial leaded through-hole package
What are the FWR Series Fusible Wirewound Resistors?
The FWR is an axial leaded fusible wirewound resistor that combines the function of a precision resistive element with the protective behaviour of a fuse. Under normal operating conditions it performs as a standard wirewound resistor, maintaining the resistance value and stability expected of wire wound construction. Under abnormal conditions — such as a sudden surge in supply voltage, a downstream circuit malfunction, or a sustained overload — the resistive winding is designed to open the circuit safely and reliably, preventing fire, further component damage, and hazardous heat generation.
The resistive element is formed by winding a carefully selected resistance wire around a ceramic core. The ceramic substrate provides dimensional stability at elevated temperatures and ensures the component retains its mechanical integrity during a fault event. The body is encapsulated in an insulated resin coating that meets UL94V-0 flammability requirements, preventing ignition or propagation of flame under overload conditions. Tinned copper leads provide reliable solderability for through-hole PCB assembly.
The FWR series covers power ratings of 1W, 2W, 3W and 5W, with a resistance range of 0.1Ω to 200Ω and a tolerance of ±5%. The temperature coefficient of resistance is ±300ppm/°C, consistent with the wirewound construction, and the operating temperature range extends from −55°C to +200°C. Dielectric withstanding voltage is AC 500V for one minute, confirming suitability for mains-referenced circuits. Short-time overload performance is rated at five times the nominal power for five seconds, with a resistance change limit of ±2.0%. The maximum working voltage for each variant is defined by the square root of the product of rated power and resistance value, ensuring the applied voltage remains within safe limits for the winding.
Resistance values are marked using a four-band colour code system on the 1W to 3W variants, with an additional white band identifying the component as fusible so that it can be distinguished from non-fusible wirewound types during inspection and rework. The 5W variant carries printed marking. The FWR is RoHS compliant and is available in standard axial taped packaging to support automated through-hole assembly processes.
FWR Series Fusible Wirewound Resistors Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: FWR
Resistor type: Wire wound
Description: Fusible
Power Rating: 1W, 2W, 3W, 5W
Resistance (Ω): 0.1~200
Tolerance (%): ±5
TCR (ppm/C): 300
Applications of the FWR Series Fusible Wirewound Resistors
Where RARA wire wound resistors are deployed in the field.
Power supply inrush current limiting — single-component protection at the input stage of AC-DC converters, combining series resistance with fault-clearing behaviour
White goods and domestic appliance protection — motor control circuits, heating elements and pump drives in washing machines, dishwashers and refrigeration compressors requiring combined resistive and overcurrent protection
Inverters and UPS systems — protective series elements in DC bus and gate drive circuits where a fault-clearing component is required without the need for a separate fuse
Lighting and ballast circuits — current limiting and protection in fluorescent, HID and LED driver circuits operating from mains voltage
Energy and utility metering equipment — input protection and current limiting in electricity, gas and water metering modules where long-term stability and reliable fault response are required
Telecommunications and signal equipment — surge pulse protection at the input of line-powered equipment and battery-backed systems
Battery chargers and small power adapters — input protection combining a defined resistive value with a fusing characteristic to guard against short-circuit and overvoltage conditions
Industrial control panels — protective elements in relay driver circuits, PLC input modules and auxiliary power rails where a combined resistor-fuse simplifies the protection scheme
Related Products of the FWR Series Fusible Wirewound Resistors
Model: SMW
Resistor type: Wire wound
Description: Power chip
Power Rating: 2W, 3W, 5W
Resistance (Ω): 0.1~680
Tolerance (%): ±1, ±2, ±3, ±5, ±10
TCR (ppm/C): 200
Model: RQA
Resistor type: Wire wound
Description: Ceramic encased
Power Rating: 5W~20W
Resistance (Ω): 0.1~100k
Tolerance (%): ±5, ±10
TCR (ppm/C): 260, 400
Model: RW
Resistor type: Wire wound
Description: Wire wound
Power Rating: 0.5W~10W
Resistance (Ω): 0.1~680
Tolerance (%): ±1, ±2, ±3, ±5, ±10
TCR (ppm/C): 260 max.
Model: PWR
Resistor type: Wire wound
Description: Precision wire wound
Power Rating: 0.5W~10W
Resistance (Ω): 0.1~100k
Tolerance (%): ±0.1, ±0.25, ±0.5, ±1, ±2
TCR (ppm/C): 20, 50, 90
Why Choose RARA Wire Wound Resistors
What sets RARA apart for engineers and procurement managers in industrial and automotive markets.
01
Widest Design Range
From 0.5W precision types to 12kW edge wound assemblies — one wire wound product family covering precision, ceramic-encased, fusible, non-flammable, and high-power variants.
02
Precision Available
The PWR series delivers ±0.1% tolerance and TCR as low as 20 ppm/°C — precision wire wound performance for instrumentation and measurement circuits.
03
Automotive Qualified
The AQL ceramic-encased series is AEC-Q200 qualified for automotive-grade reliability in EV battery management, HVAC, and powertrain applications.
04
Global Track Record
Trusted by Siemens, Rockwell, Toshiba, Schneider Electric, LG, and Hanwha — a customer base built on decades of consistent, certified performance.
