To Next Page

To Previous Page

6.1.2 Selecting cables

Take the following criteria into account when selecting the connecting cables:

• Rated current

• Rated voltage

• If required, service factor

• System-dependent conditions, such as ambient temperature, routing type, cable cross-

section as de󹪝ned by required length of cable, etc.

• Con󹪝guration notes

• Requirements according to IEC/EN60204‑1

• Dimensioning for bundled cable routing, e.g. according to DINVDE0298Part4 or

IEC60364-5-52

6.1.3 Thermal protection

• Protect every explosion-protected machine according to EN / IEC 60079-14 Chapter "Rotating

electrical machines".

• For machines with type of protection increased safety "eb", select the overcurrent device with

current-dependent delayed trip so that the tripping time, which should be taken from the

characteristic of the switch for the ratio I

/ I

of the machine to be protected, is not longer

than the safe locked rotor time (t

). Take the ratio I

/ I

as well as the safe locked rotor time

) from the rating plate. Set the protective device to the rated current. Use a trip unit

certi󹪝ed according to directive 2014/34/EU or the corresponding national regulations.

• For machines with increased safety "eb" type of protection, in the event of a locked rotor the

protective device must disconnect within the safe locked rotor time (t

) speci󹪝ed for the

relevant temperature class. Protect electrical machines for heavy duty starting (acceleration

time > 1.7 x t

time) according to the speci󹪝cations of the EU-type examination certi󹪝cate

using a function to monitor starting.

Direct monitoring of the winding temperature is permissible as a means of thermal machine

protection, provided that this is certi󹪝ed and speci󹪝ed on the rating plate.

• With pole-changing machines, separate, interlocked protective devices are required for each

speed step. Devices with an EU-type examination certi󹪝cate are recommended.

Siemens SIMOTICS XP 1MB 1 Series User Manual

Questions and Answers: