SARRACS - safety remote racking system with custom torque

06/01/2005 - Volume II - Issue II

The purpose of SARRACS is to allow operators to rack circuit breakers "in" and "out" from a distance that insures operator safety in the event of an electrical failure of the breaker and/or cell. Picture 1 (see below) shows required procedure and Personal Protective Equipment required by NFPA 70E / OSHA. Picture 2 (see below) shows required procedure and Personal Protective Equipment required using the SARRACS.

 

The design of the manual racking systems in vintage switchgear utilized the operator to visually and physically detect alignment and other problems during the racking procedure. By removing the operator from the immediate area of the breaker, we greatly enhance his safety but give up the ability to monitor the racking procedure and adequately protect the equipment. The SARRACS not only supplies operator protection, it also supplies equipment protection with its Custom Torque feature.

Breaker safety

Utilizes state-of-the-art SIMATIC S7-200 PLC from Siemens

  • Digital position control for consistent and accurate breaker engagement

  • Customized position-torque control provides protection to minimize equipment damage

  • Auto revers (optional)

  • Speed control

  • Ramp control

  • Ramp up/ ramp down

  • Interface options.

Operator safety

  • Remote operation-personnel safely operate breaker from a distance of up to 40 feet

  • Reduces the need for special personal equipment (PPE). Since operator is outside the flash boundary, the need for protective flash clothing is reduced.

  • Completely portable - ball bearing wheels, casters, and transport handle for easy maneuvering.

Flexibility

  • Programmable to allow for varying torque profiles and mechanical requirements of individuals breakers in a line-up

  • Mechanically adjustable to allow for different circuit breakers in the same line-up

  • Portable and self-contained - easy to store and transport-strong but light (App. 200 lbs)

  • Designs available for most circuit breakers.

The SARRACS supplies the following functions:

  1. Remote operation of the Power Assist Unit via Touch Screen Control Panel.
  2. A Power Assist Unit to eliminate the need for "Manual" racking A.C. Gear Motor with Variable Frequency Control; Mobile Steel Frame with Vertical Adjustment (electrical); Wheel Brakes for stationary stability of Mobile Frame.
  3. Basic control logic to start, stop, track the location of the circuit breaker, and monitor torque, during the racking process via Siemens S7-200 PLC, digital encoder, and Variable Frequency Drive.
  4. Protection of the circuit breaker and cell against equipment misalignment, jamming, and other equipment failures during the racking procedure. Position tracking by the digital encoder and torque monitoring by the current sensor allows the Custom Torque feature to establish a Torque Profile for that particular switchgear breaker. This Torque Profile allows for very accurate monitoring  and protection during the racking procedure.
  5. Adaptor as required to interface between Power Assist Unit and desired breaker or breakers.

Typical Operating Procedure

 

  1. Operator checks position of circui breaker in the cell and assures that the breaker is open.
  2. Operator connects power to the SARRACS by plugging into 110 VAC outlet.
  3. Operator positions the SARRACS and engages the breaker racking mechanism.
  4. Operator secures the SARRACS via its brakes or other means as required.
  5. Operator takes TouchScreen Control Panel and positions himself in safe location where breaker racking can begin.
  6. Operator inputs breaker to be racked: its close/open condition and its beginning position (connect or disconnect) via TouchScreen Control Panel.
  7. Operator initiates racking via TouchScreen Control Panel.
  8. The SARRACS will start in the direction dictated by the operator.
  9. As the breaker leaves its original position, the "Position Indicating Light" for that position will go out. Position and Current are monitored on the TouchScreen Control Panel.
  10. The SARRACS will continue to run until the breaker reaches its new location.
  11. When the breaker arrives at its new location, the "Position Indicating Light" will come on, and the SARRACS will stop.
  12. Operator turns power off to the racking system via the "Power Off" switch on the TouchScreen Control Panel.
  13. Operator "Unplugs" the SARRACS.
  14. Operator disconnects and disengages the SARRACS from the breaker.
  15. Operator checks position and condition of the breaker in the cell.
  16. Operator returns the SARRACS to storage.