EW Series Edge Wound Resistor Assemblies
Resistor type: Edge wound wirewound assembly
Power rating: 3kW to 12kW continuous
Resistance range: 0.05Ω to 48Ω
Tolerance options: ±5% and ±10%
TCR: 800 ppm/°C maximum
Dielectric strength: 3kV AC
Construction: Resistance wire edgewound on ceramic insulators, mounted on steel support frame
Terminal options: Screw bolt and quick-fit tab terminals; adjustable tapping clip available
What are the EW Series Edge Wound Resistor Assemblies?
The EW series is a range of high-power edge wound resistor assemblies designed for continuous industrial duty in motor control, dynamic braking, and energy dissipation applications. Each assembly is constructed by winding a flat resistive alloy strip on its edge around ridged ceramic insulators, forming a helical coil element that is mounted on a central steel support frame. This edgewound construction increases the exposed surface area of the resistive element relative to its mass, enabling efficient convective heat dissipation and making the assembly capable of sustaining rated power continuously without forced cooling in free-air conditions.
Power ratings span 3kW to 12kW, positioning the EW series between single-element edgewound units and fully ventilated load bank assemblies. The resistance range of 0.05Ω to 48Ω accommodates the low-impedance requirements typical of DC bus braking circuits and motor starting networks, where high current must be handled at relatively low voltage. Tolerance options of ±5% and ±10% are available across the range, with a TCR of 800 ppm/°C maximum — characteristic of the iron-chromium-aluminium and nickel-chromium alloys commonly used for edgewound elements operating at elevated temperatures.
The open coil geometry of the edgewound element allows unrestricted airflow through the assembly during operation, which enhances natural convection cooling and permits the structure to cycle thermally without imposing mechanical stress on the mounting frame or ceramic insulators. The steel support construction provides both mechanical rigidity and secure terminal mounting, with screw bolt and quick-fit tab terminal options to suit different panel-wiring and cabinet installation environments. An adjustable tapping clip option is available, allowing the effective resistance value to be set or trimmed in the field without replacing the assembly — a practical feature for motor starting and speed control circuits requiring staged resistance adjustment. Assemblies can also be supplied in banked configurations for increased total power ratings beyond the 12kW single-assembly limit.
EW Series Edge Wound Resistor Assemblies Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: EW
Resistor type: Wire wound
Description: Edge wound assembly
Power Rating: 3kW~12kW
Resistance (Ω): 0.05~48
Tolerance (%): ±5, ±10
TCR (ppm/C): 800 max.
Applications of the EW Series Edge Wound Resistor Assemblies
Where RARA wire wound resistors are deployed in the field.
Motor drive and variable-frequency drive systems — dynamic braking resistors for regenerative energy dissipation during deceleration
Crane, hoist, and overhead travelling crane drives — braking and speed control resistors for repetitive-duty lowering and positioning cycles
Elevator and escalator controls — braking resistor assemblies for traction drive deceleration and emergency stop duty
Electric forklift and mine locomotive drives — high-current braking and plugging resistor banks for continuous-duty industrial vehicles
Motor starting circuits — staged starting resistors for slip-ring induction motors and reduced-voltage starting applications
Neutral grounding and earthing resistor assemblies — fault current limiting in medium-voltage distribution networks and generator installations
Load bank and discharge applications — resistive load elements for generator testing, UPS discharge, and capacitor bank energy dissipation
Renewable energy systems — dump load and crowbar resistor banks for wind turbine pitch control and inverter overvoltage protection
Industrial test equipment — high-power resistive loads for motor and drive test rigs requiring stable, continuous dissipation
Pulse current and short-time overload circuits — high thermal mass elements for applications demanding short-duration overload capacity beyond rated continuous power
Related Products of the EW Series Edge Wound Resistor Assemblies
Model: EWS
Resistor type: Wire wound
Description: Edge wound
Power Rating: 400W~1600W
Resistance (Ω): 0.02~1
Tolerance (%): ±5, ±10
TCR (ppm/C): 800 max.
Model: K
Resistor type: Wire wound
Description: Non-flammable
Power Rating: 15W-2000W
Resistance (Ω): 1~1200k
Tolerance (%): ±5, ±10
TCR (ppm/C): 200 max.
Model: DBR
Resistor type: Wire wound
Description: Dynamic braking
Power Rating: 8kW~60kW
Resistance (Ω): 1~150
Tolerance (%): ±5, ±10
TCR (ppm/C): 800 max.
Model: RLB
Resistor type: Wire wound
Description: Load bank
Power Rating: 50kW~3000kW
Resistance (Ω): 0.1~1M
Tolerance (%): ±5, ±10
TCR (ppm/C): 200
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.
