Hilkar Compact RC Snubber filters protect electrical machines from damage caused by insulation failures which typically occur during the winding of equipment such as generators, reactors, motors and transformers. Unless certain protection measures are taken into consideration, significant losses can be incurred. Implementation of RC snubbers (high frequency transient surge suppressors) as surge protection devices, significantly reduces the direct and indirect costs related to equipment repair and cessation of business activity. RC Snubbers help to eliminate switching transients that can occur as a result of switchgear operation as well as significanly reduce the steep wave-front surges seen at load terminals.


  • Save on costs, via reduced downtime and repair costs
  • Improve operational performances, as a result of reduction in production downtime
  • Superior protection against interturn insulation failures
  • Extends lifetime of motors/transformers
  • Reduce the likelihood of pre-strike, re-strike, and re-ignition observed at circuit breakers
  • Reduce the magnitude and rate of rise of voltage (RRRV) transients
  • Ease of installation


Application Areas
  • Power Generation
  • Pulp and Paper Industry
  • Petrochemical Industry
  • Chemical Factories
  • Surface and Underground Mining
  • Water and Oil Pumping Stations
  • Railway Applications
  • Large Motors
  • Arc furnaces
  • and many other facilities using any kind of motors and/or transformers


Protections Provided
  • Protection against all practical surge peaks and rise-times
  • Withstands all the motor impulse voltage levels recommended by both CIGRE and IEEE
  • Elimination and damping of multiple pre/re-strike transients which occur during switchgear operation
  • Eliminates voltage doubling effects by cancelling refraction of surges by providing a matched cable terminating impedance and thus halving the magnitude of the surge
  • Eliminates higher harmonic current zeros through the breakers by disabling current reflection waveforms


Product Range
  • Operating Voltage: Up to 36kV
  • Compact size, up to 36 kV networks, all components (R+C+L) are contained in single case
  • Impulse Withstand Voltage: Up to 200 kV BIL
  • Variety of surge capacitance ratings depending on the site requirements and application type (ie, 0.1-2 µF)
  • Variety of surge resistance ratings depending on the site requirements and application (ie, 1-200 ohm)
  • Fully assembled, tested, and ready for interconnection



RC snubbers are also known as RC dampers or RC surpressors. A typical comparison of RC snubber protection is provided below. In CASE-A, no protection is active in the network. In CASE-B, a typical RC snubber coupled with a surge arrester is used for transient voltage waveform steepness and peak reduction while ensuring that pre-defined withstand voltage limits are not violated.

*TRV: Transient Recovery Voltage, CB: Circuit Breaker
CASE-A: No RC protection during switching

CASE-A: No RC protection during switching

CASE-B: With RC protection during switching

CASE-B: With RC protection during switching

Types Available

RC snubbers are available as custom designs between 1 to 36 kV as single or three phase 50/60Hz systems. They are mainly supplied for industrial motor & transformer, reactor and generator protection applications. The single phase and three phase RC Snubbers manufactured by HİLKAR are custom built to meet your requirements. They are composed of a combination of capacitors, resistors and surge arresters to reduce the magnitude and frequency of transient voltages observed. For requests for lower or higher system voltages please contact the factory.

Compact Filter Types

Compact Filter Types

Typical Connection Diagrams

Typical Connection Diagrams

Installation & Commissioning

Hilkar RC Snubbers are suitable for (but not limited to) installation at the following connection points depending on the application:

  • - In the protected equipment’s terminal box or associated switch panel, between each phase to ground.
  • - Connected to the equipment terminal box via a minimum of 3x25/16 mm2 cable with the provided accessories.
  • - RC Snubbers must be grounded to the motor/transformer ground or the breaker earth connection.
  • - When porcelain bushings are used, connections to the bushings must be through flexible connections, so that any shock or vibration that may be transmitted to the bushing during transportation or in service, does not cause any damage.
  • - The fixing nuts shall not be tighter than 20 Nm.
  • - The flexible leads can be shortened but cannot be extended and must be directly connected to the protected equipment terminals.


  • - Mounting brackets or clamps
  • - Connection cable and flexible leads (optional)