SR20M_/E___/RX Slip Ring Assembly

The SR20M_/E___/RX Slip Ring Assembly has 20 slip ring circuits, an integrated encoder, and a Type M/R (2.000″ diameter) rotor.


  • 20 slip ring connections
  • Encoder rotation sensor
  • Available with or without weatherproof seals
  • Type M/R (2.000″ diameter) rotor
  • Circular connectors on stator and rotor
  • Instrumentation quality rings & brushes
  • Sealed, corrosion resistant metal housing
  • Lightweight and compact


The SR/ERT Series is used when a slip ring and/or a rotation sensor needs to be mounted at the end of a rotating shaft. The gold alloy slip rings are used to make high quality electrical connection to strain gages, thermocouples, or other sensors that have been installed on rotating machinery. Current capacity is 0.5A per connection and the maximum peak resistance variation is 0.1 ohm. The rotation sensor is used to measure rotational velocity, angular position, and direction of rotation. The rotation sensors do not use any of the slip ring connections.

The housings are approximately five inches long. They weigh about 24 ounces. The rotors are made from high strength stainless steel. The stators are lightweight, nickel-plated, aluminum. Threaded holes are provided for attaching a rotation restraint. Connection information is permanently engraved on the housing. Circular connectors or solder terminals are offered as wiring terminations. 

All housings in this series have been designed to accept contacting rotary seals. Units ordered with these seals (choice W) are completely weatherproof and can survive days of total submersion. The seals limit operation to 2000 rpm maximum. Most wet weather applications, like automotive wheels, are within this range. For higher speeds in dry conditions, order units without the contacting rotary seals. Units without seals are capable of the following speeds:

  • 20 rings – 4,000 rpm

Unit torque with seals is 21 inch-ounces. Unit torque without seals is three inch-ounces. If the application requires a high speed, weatherproof slip ring & encoder, consider units with non-contacting labyrinth seals in the SR/E512 series.




Encoder (E)

Rotation sensor choices E256, E360, E500, & E512: Four optical encoder resolutions are offered, see the table below. Each of these encoder choices has 4 outputs, shown graphically below. Outputs A and B are in quadrature (exactly 90° out of phase). Output I is an index pulse. Output A+B is the exclusive OR of A and B, which doubles the basic resolution of the encoder. The outputs, 0 to 5 volt pulses, can drive TTL loads. The encoders will operate from a +5 to +20 Vdc, 100 mA power supply. Temperature range is -40F to +212F. The encoders have metal code wheels and rugged electronics so they tolerate shock and vibration. They are also protected from incorrect wiring up to 20 volts. Accuracy of encoder systems is 0.25° (maximum cumulative error).

Last Modified: Sep 7, 2017 @ 11:41 am