Widap power resistors, braking units, and precision potentiometers

Swiss manufacturer Widap AG produces advanced power resistor technology: aluminium-housed wire-wound resistors HPR, heavy steel grid assemblies, cemented modules, and high-precision angle potentiometers.

High power resistors in aluminium housing HPR / VHPR

Wire-wound power resistors in aluminium housing series HPR and VHPR with nominal power from 60 W to 2500 W. The heavy-duty design provides high dielectric strength and superior pulse withstand capability for frequency converters. The protective cover prevents particle ingress and touch hazards.

Special alloy resistance wire wound on ceramic core inside an aluminium profile.
Protection degree rating from standard IP50 up to sealed IP65 enclosure execution.
Integrated bimetallic thermal contact or optional PTC sensor for temperature cutoff.
Application in dynamic braking circuits and snubber networks for AC/DC drives.

Steel grid and heavy grid resistor banks

Widap steel grid resistors are assembled from punched chromium-aluminium steel elements with reinforcements into banks of 3 to 50 plates. The open construction offers superior heat dissipation across large surface areas. The assemblies resist severe vibration and mechanical shocks in heavy industry.

Punched heat-resistant chromium-aluminium steel elements mounted on tie bolts.
High power dissipation rating and stable resistance during cyclic overload.
Full dimensional and electrical compatibility with ABB, Siemens, and AEG banks.
Starting, regulating, and discharging applications in cranes and test fields.

Industrial dynamic braking resistors for drive systems

Widap dynamic braking resistors absorb regenerated energy during motor deceleration in variable frequency drive systems. Tailored to specific engineering requirements with natural convection or forced fan air flow, these assemblies deliver dependable energy absorption across demanding duty cycles.

Rapid dissipation of kinetic energy during frequent start-stop machinery cycles.
Intrinsically safe HPRF series with built-in short circuit protection design.
Integrated thermal protector switch signals drive control upon thermal overload.
Direct mounting on enclosure backplates or external heat sink assemblies.

Cement-coated wire-wound power resistors

Widap cemented wire-wound resistors feature a cylindrical or flat-oval ceramic core with precision alloy resistance windings. An inorganic flameproof cement coating delivers superior electrical insulation, pulse surge endurance, and protection against demanding ambient industrial factors.

Flat-oval profile provides superior heat conduction in compact equipment layouts.
Continuous nominal power rating span from 5 W up to 1000 W single elements.
Impulse-resistant and low-inductance non-inductive winding configurations.
Resistant to moisture, corrosive plant atmospheres, and conductive dust.

Traction and braking resistors Sécheron BBC

Widap acquired the complete manufacturing assets and technical designs for Sécheron and BBC railway resistor lines. Series BW, RHW, RHK, RM, and SF serve propulsion and dynamic braking circuits across locomotives, multiple units, and rapid transit rolling stock under rigorous operational standards.

Exact OEM form and fit for one-to-one drop-in replacement in undercar frames.
Heavy insulation barrier withstands track shock, rock debris, and moisture.
Heavy-duty industrial grid lines HC and HJ for high-torque industrial motors.
Supply of newly manufactured units and overhaul overhaul support kits.

Precision wire-wound and motorized potentiometers

Widap precision single-turn and multi-turn wire-wound potentiometers in series 718, DP, and D deliver accurate position feedback and setpoint adjustment. Precious metal wipers and collector rings guarantee exceptional signal fidelity and extended operational life in automated control cabinets.

Single-turn precision models series 718 with bushing or servoflange mountings.
Wiper and collector elements fashioned from precious metal alloy compositions.
Multi-turn and multi-gang tandem configurations for critical analog controls.
Motor-driven potentiometers with reduction gearbox for automated positioning.

Selection of Widap HPR and VHPR aluminium-housed resistors

When engineering variable frequency drive assemblies, selecting Widap series HPR and pulse-proof series VHPR resistors relies on peak braking energy and minimum ohmic resistance.

The extruded aluminium profile with exterior fins delivers efficient heat transfer through natural convection or direct attachment to cabinet mounting plates.

Specialized alloy resistance windings mounted on high-grade ceramic cores are embedded within a thermally conductive dielectric compound that prevents coil movement under vibration.

An integrated bimetal thermal protector switch signals operational overload to the drive controller, safeguarding sensitive inverter power modules against thermal stress.

Design and heat dissipation of steel grid resistor assemblies

Widap steel grid resistor banks built from punched chromium-aluminium steel elements are developed for demanding energy dissipation across metallurgical, crane, and mining machinery.

Element packs holding 3 to 50 plates are assembled on insulated tie bolts with ceramic spacers, facilitating unrestricted cooling air flow throughout the bank structure.

The high-temperature alloy maintains mechanical strength and dimensional stability through intense thermal cycles without distortion. Standardized mechanical interfaces guarantee seamless replacement for legacy resistor banks across European industrial installations.

Engineering parameters for dynamic motor braking systems

During dynamic deceleration cycles on high-inertia machinery, Widap dynamic braking resistors absorb rotational kinetic energy converted by the drive motor into electrical energy.

The minimum allowable resistance rating is governed by the peak current threshold of the inverter braking chopper, while average dissipation capacity depends on operational duty cycle duration.

For demanding industrial duty cycles with brief intervals between stops, engineers specify robust HPRF modules engineered with enhanced thermal storage capacity or custom steel grid banks equipped with auxiliary forced ventilation units.

Application features of cemented wire-wound power resistors

Widap cemented wire-wound resistors in flat-oval and tubular configurations are extensively utilized in capacitor discharge circuits, snubber networks, and power supplies.

A protective coating of inorganic cement shields the resistance wire from oxidation, moisture ingress, and airborne industrial contaminants. The flat-oval cross section minimizes parasitic inductance while enhancing thermal radiation compared to conventional cylindrical cores.

These resistors span continuous nominal power ratings from 5 W to 1000 W and provide versatile terminal options for screw or solder connection.

Sécheron BBC railway resistor heritage in modern rail fleets

Widap maintains and manufactures the complete resistor portfolio of Sécheron and Brown Boveri Company for railway and transit rolling stock.

Traction and braking resistor lines BW, RHW, RHK, RM, and SF conform strictly to international rail standards for shock endurance, insulation coordination, and weather resistance.

Fleet operators can source complete factory-tested resistor frames for locomotives and passenger trains or procurement kits for routine maintenance, ensuring drop-in dimensional compatibility without modifications to undercar equipment bays.

Precision potentiometers series 718 in automated motion controls

Single-turn and multi-turn wire-wound potentiometers from Widap in series 718, DP, and D serve as reliable angular position feedback sensors and manual parameter dials in industrial equipment.

The internal structure combines a precision resistance coil with precious metal wiper contacts, delivering low contact noise and high signal linearity throughout extended duty cycles.

Bushing and servoflange mountings facilitate rigid mechanical alignment with drive shafts, while motorized variants with miniature gearboxes enable automated remote setpoint tuning from programmable automation controllers.

Widap and model names are trademarks of their respective owners and are used only to identify the equipment for which we source parts. SpareX is not an official dealer, distributor or representative of Widap and is not affiliated with the trademark owner. Origin, documents and warranty are stated for each item in the quotation.