Buffer/Slip Resistors

Buffer/slip resistors for special applications

  • Rugged and Reliable

  • Cheapest option to minimize the current spikes

  • Power Savings options available

  • Customized for each application

  • Available with a slip of 5, 7, 10 or 15% as standard


Slip/Buffer resistors are required when excessive loads are to be expected during operation, for example in a crusher drive. Slip resistors limit the torque in rotor circuits in slip ring motors when the motor is starting or is in operation. Torque limiting is normal during continuous operation. Should an overload occur, the slip resistor reduces the nominal speed and limits the motor torque. In normal operation the actual nominal speed remains constant.

Pioneer Slip resistors are made from SS 401. These are non corrosive and stable resistors. The slip/buffer resistors are available in various ratings from 1-5 minutes or it can be intermittent or continuous. The Slip resistors are available with a slip of 5, 7, 10 or 15% as standard. The degree of protection of enclosure is as per customer’s requirement.

Major applications are Crusher Drive, Cutter drive, Chopper drive,etc…OR where the flywheel effect on motor.

It’s used in series with rotor circuit. It can be continuous or can be bypass/inserted in circuit via contactor when required.


Front compartment will be dust and vermin proof, provided with suitable gaskets and will be housed with Cable termination arrangement. As optional we also provide suitable rating Power Contactor to bypass the buffer resistance.

Back compartment will be well ventilated, natural cooled type, and will be housed with resistance banks. The resistance will be stainless steel coil type with high thermal capacity and will be designed for temperature rise 350°C. The resistance coils will be mounted on angle iron structure with proper support to absorb the vibration and stresses that occur during transit/fault. The termination box and Resistance box are mounted in the same unit with partition in between. All power connections are done by solid copper jumpers through polypropylene sheets.

Generally its design for natural cooling. For larger ratings can be design with adequate number of cooling fans to take away the heat generated during operation.


The models are depend on the Qty, Ratings and Combination of the resistance elements.

  1. BR-12

  2. BR-24

  3. BR-36

  4. BR-48

  5. BR-60

  6. BR-72

  7. BR-84

  8. BR-96

  9. BR-120

  10. BR-132

  11. BR-144

  12. BR-156

  13. BR-168

  14. BR-180



  • Resistance elements

  • Insulators


  • Power contactor (for bypass)

  • Current relay to operate the Power Contactors

  • Temperature Monitoring

  • Cooling fan

Required details to quote:

  • Type of Driven machine

  • Motor Power (KW)

  • Rotor Voltage (V)

  • Rotor Current (A)

  • Motor rated Speed

  • Single or Twin Drive

  • Detail of connected load with shaft power

  • Load Torque cure of driven machine

  • % slip (5, 7.5, 10 and 15% slip is standard)

  • Required tapping ?


To start the slipring motors of following:

  • Crusher

  • Chopper

  • Shredder

  • Fibrizer


  • Cement & Mineral

  • Mining

  • Steel

  • Sugar

Do's and Don'ts:


  • Keep the resistance panel in well ventilated place

  • Generated hot air should come out from the panel room/area to maintain/control the temperature of resistance elements