Control and protection switching gear (CPS)

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CPS or “starter-controllers” are designed to fulfil control and protection functions simultaneously (overload and short-circuit). In addition, they are designed to carry out control operations in the event of short-circuit.

They can also assure additional functions such as insulation, thereby totally fulfilling the function of “motor starter unit”. They comply with standard IEC 60947-6-2, which notably defines the assigned values and utilisation categories of a CPS, as do standards IEC 60947-1 and 60947-4-1.The functions performed by a CPS are combined and coordinated in such a way as to allow for uptime at all currents up to the Ics working short circuit breaking capacity of the CPS. The CPS may or may not consist of one device, but its characteristics are assigned as for a single device.

Furthermore, the guarantee of “total” coordination of all the functions ensures the user has a simple choice with optimal protection which is easy to implement.

Although presented as a single unit, a CPS can offer identical or greater modularity than the “three product” motor starter unit solution. This is the case with the Schneider Electric “TeSys U” starter-controller (see Figure N86).

Fig. N86 – Example of a CPS modularity (TeSys U starter controller by Schneider Electric)

Additional functionalities can also be installed with regard to:

  • Power: reversing block, current limiter,
  • Control:
    • Function modules, alarms, motor load monitoring, automatic resetting, etc,
    • Communication options such as Modbus-RTU (a.k.a. SL), Profibus-DP, DeviceNet, CAN-Open, AS-I, etc,
    • Auxiliary contact modules.
Fig. N87 – TeSys U Communication functions
Available functions Standard Advanced Multi-function
Starter status (ready, running, with default)
“Monitoring” function
Thermal alarm
Remote resetting by bus
Indication of motor load
Defaults differentiation
Start and Stop controls
Alarms (overcurrents…)
Parameter setting and protection function reference
“Log file” function
       Information conveyed by bus and functions performed