Layout Of Holding Brakes; Motor Encoder; Options - Bosch Rexroth MAD Project Planning Manual

MAD / MAF Asynchronous Housing Motors
Servo applications
Electrically releasing holding brake
9.10.4

Layout of holding brakes

Dynamic sizing
Project planning recommendation
9.11

Motor encoder

9.11.1

Options

Clamp the holding brake only while the motor is at standstill, i.e.,
after the drive has signaled that the motor has come to a stand‐
still.
The electrically releasing holding brake should not be used for main spindle
applications because the brake may not only be under extreme wear and tear
but may also be destroyed if the holding brake is applied unintentionally at
high speeds (e.g., voltage failure or wire break).
The electrically releasing holding brake serves to hold axes at standstill and
with deactivated drive enable. If the supply voltage fails and drive enable is
deactivated, the electrically releasing holding brake is applied automatically.
● Do not use the holding brake as an service brake for moving axes.
If the brake is repeatedly activated with the drive rotating or the allowed brake
energy is exceeded, premature wear and tear may occur.
The electrically clamping holding brake is inappropriate for servo applications
because there will be no clamping of axes in the de-energized state.
Holding brakes on motors are basically not designed for service braking. The
effective braking torques are physically conditionally different in static and dy‐
namic operation.
Normal operation and EMERGENCY
STOP
In normal operation, using the holding
brake for clamping of a standstill axes,
the "statistic holding torque" (M4), applies
as indicated in the data sheets.
For EMERGENCY STOP to deactivate
an axis (n < 10 min -1 ), a "dynamic brak‐
ing moment" acts (M ) - sliding friction.
dyn
Therefore, note the following description of dynamic sizing.
Tab. 9-14: Dynamic sizing
The load torque must be smaller than the minimum dynamic moment M
which the holding brake can provide. Otherwise the dynamic holding brake
torque is not sufficient to stop the axes.
If a mass is to be decelerated in a defined time or in a defined route, the addi‐
tional mass moment of inertia of the whole system must be taken into ac‐
count.
To ensure construction safety, reduce the required holding torque to 60% of
the static holding torque (M4) of the holding brake.
"S2": Single-turn absolute encoder with EnDat2.1 interface. Sine/cosine sig‐
nals 1 V with 2048 lines per revolution and absolute period assignment
pp
event of faults
For fault conditions to deactivate a mov‐
ing axis (n ≥ 10 min ), a "dynamic brak‐
-1
ing moment" acts (M
dyn
M4 > M
dyn
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Application notes
) - sliding friction.
dyn