33 / 74
MKE Synchronous Servomotors
Features and functions
Bosch Rexroth AG
R911402016, Edition 02
•
In case of an emergency stop or voltage drop,
the brake operation is only allowed to a lim-
ited extend. Up to 500 breaking cycles from
speed 3000 1/min can be performed,
whereas the maximum switched energy per
emergency stop of the brake must not be
exceeded. The number of brake applications
per hour is 20, whereas a uniform scheduling
is a precondition. Specifications about the
maximum switched energy per emergency
stop on demand.
•
Idle time after an emergency stop before
restarting ≥
3 minutes.
CAUTION
Malfunctions due to wear
Impermissibly high wear due to breaking from
speed by exceeding the specified emergency
stop properties.
Ensure the functionality of the brake in normal
operation, due to voltage control, current moni-
toring, cyclic control of the brake holding torque,
for example.
The rated voltage to apply the brakes is
24
V
DC
±10%.
The voltage supply of the holding brake has to be
designed so as to guarantee under the worst
installation and operation conditions that a suffi-
cient voltage 24
V
DC
±10% is available at the
motor in order to release the holding brake.
The voltage drop ΔU on the brake supply can
approximately be calculated for copper conduc-
tors using the following formula:
Fig. 3: Voltage drop of brake supply
ΔU Voltage drop [V]
ρ
Cu
Specific resistance of copper [Ω*mm
2
/m]
l
Cable length [m]
q
Conductor cross-section
[mm
2
]
I
N
Rated current [A]
CAUTION
Malfunction in case of exceeded tolerance of the
rated voltage (switching voltage)
For safe switching of the holding brake, a rated
voltage of 24
V
DC
±10% is required at the
motor.
Ensure correct dimensioning of the supply wires
(wire length and cross-section) for the holding
brake.
The control voltage can be reduced using the
energy saving function after safely releasing the
brake, see
Chapter “Energy saving function for
.
The holding brake in the motor is intended for
direct connection to the Bosch Rexroth con-
troller.
The protective circuit for switching holding
brakes (inductive load) is not integrated in the
MKE motors; in Bosch Rexroth drive systems it is
integrated in the control units.
