Holding Brake; Residual Risks - Bosch rexroth MSK030-NSNN Series Operating Instructions Manual

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Operating instructions

1.5 Holding brake

In normal operation, use the optional holding brake only when at a standstill and
when performing the drive-internal brake check. In these cases, only low temper-
atures (T < 100 °C) exist and no sparks are generated because critical sliding of
the brake linings does not occur.
Control holding brake
The voltage supply of the holding brake is to be designed such that the voltage
available at the motor for bleeding the holding brake is sufficient even in the
most unfavorable case during installation and operation (see also Rexroth
IndraDrive Drive Systems DOK-INDRV*-SYSTEM*****-PRxx-EN-P, Chapter "Specifi-
cation of control voltage")
The voltage supply of the holding brake has to be designed so as to guarantee
that a voltage of 24 V ±10% is available at the motor in order to safely operate
(release and apply) the holding brake.
The voltage arriving at the motor is influenced by cable length and
the properties, e.g. conductor resistance.
If a fault occurs during operation, causing a voltage deviation, this fault must be
detected and eliminated immediately. The failure can be identified, for example,
using a monitoring device for undervoltage.
Event of fault
Only in an event of fault, i.e. in the case of a fault in the system, may the brake
be activated when the motor is turning, e.g. in order to prevent a dangerous low-
ering of vertical axes. In this case, sparks may be generated in the brake and in-
creased temperatures may occur within the motor. When a fault occurs, the op-
erator must eliminate it immediately.

1.6 Residual risks

Overloading
When the motor is overloaded, including cases where errors in the mechanical
or electrical equipment of the machine cause such overloading, high tempera-
tures may occur that result in explosion hazards.
An operation in explosive dust-atmosphere can built a layer on the motor during
a residence time, which does no longer ensure a sufficient motor cooling (see
chapter 1.13.2 "Repair" on page
Grounding and discharge currents
Variable-speed drive systems cause unavoidable discharge currents. If the
grounding connector in the motor cable and the second separate grounding con-
nector on the motor housing are not connected as specified or are interrupted
due to corrosion or other defects during their lifetime, the discharge current
Bosch Rexroth AG R911323850_Edition 05
MSK Motors Operation For Potentially
18).
Explosive Areas