Dimensioning Power Cable; Cable - Handling And Installation Recommendations - Bosch Rexroth MKE Series Project Planning Manual

Project Planning Manual | Rexroth MKE Synchronous Motors
Protective or equipotential bonding
conductor
8.4

Dimensioning Power Cable

Speed n ≥ 0.01 Hz "rotating motor"
Speed n ≤ 0.01 Hz "rotating motor"
8.5 Cable – Handling and Installation Recommendations
General
The connection of the protective conductor terminal is to be made over the
power cable in the protective conductor into the terminal box of the MKE motor.
An additional connection of a protective or equipotential bonding conductor is
prescribed for MKE motors according to EN 50014: 1992. All MKE motors have
to be grounded over the additional connection part (protective conductor clamp
on the motor flange). Protective conductor cross-section see
protective conductor" on page
The cables' cross-sections specified and calculated in this Bosch Rexroth doc‐
umentation base upon RMS currents and the assumption of a "rotating motor".
The basis for this calculation are the continuous currents at standstill which are
given as crest values in the technical data chapter of this documentation.
The relevant electric currents are related as follows:
I relevant electric current for the dimensioning of the cable
(cable)
I Constant current at standstill of the motor (crest value)
dN(motor)
Fig.8-6: RMS and peak values ("rotating motor")
In general, it suffices to dimension according to the RMS current for a "rotating
motor".
I relevant electric current for the dimensioning of the cable
(cable)
I Constant current at standstill of the motor (crest value)
dN(motor)
Fig.8-7: RMS and peak values ("motor at stillstand")
In individual cases, for applications of longer time intervals (guide values see
Fig.:8-8) which require the continuous torque at standstill at speed = 0 min
is recommended to realise the cable dimensioning according to the crest values
("motor at standstill") given in the Technical Data.
Motor type
MKE037
MKE047, -098, -118
Fig.8-8: Longer-term operation
The recommended minimum cross-sections specified are to be
checked by the machine / system manufacturer for the machine- /
system-specific conditions and, if necessary, corrected.
The maximum operating time of cables largely depends on the mode of instal‐
lation and environmental factors at the place of installation. Since there is a
great variety of operating conditions, the following recommendations can only
be a help in order to provide for a faultless operation of the lines (cables) as
long as possible.
Electric Drives | Bosch Rexroth AG
and Controls
Connection Technique
66.
Period of time
10 min
15 min
69/131
fig. 8-2 " Additional
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