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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 defined by required length of cable, etc.
• Configuration 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
than the safe locked rotor time (t
(t
certified 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
relevant temperature class. Protect electrical machines for heavy duty starting (acceleration
time > 1.7 x t
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 certified and specified on the rating plate.
• With pole-changing machines, separate, interlocked protective devices are required for each
speed step. Devices with an EU-type examination certificate are recommended.
See also
Thermal protection (Page 51)
1MB..1/2/3/4 - shaft heights 63 ... 355
Operating Instructions, 11/2023, A5E52779900A
) from the rating plate. Set the protective device to the rated current. Use a trip unit
E
time) according to the specifications of the EU-type examination certificate
E
/ I
of the machine to be protected, is not longer
A
N
). Take the ratio I
/ I
as well as the safe locked rotor time
E
A
N
Electrical connection
6.1 Connecting the machine
) specified for the
E
79
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