Selecting Holding Brakes - Bosch Rexroth MAD Project Planning Manual

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Application notes
9.10.3

Selecting holding brakes

General
Main spindle applications
Electrically clamping holding brake
Bosch Rexroth AG R911295781_Edition 11
● EN 954; ISO 13849-1 and ISO 13849-2 Safety-related parts of control
units
● Information Sheet No. 005 "Gravity loaded axes (vertical axes)" - pub‐
lished by: Technical Committee Mechanical Engineering, Manufacturing
Systems, Steel Construction
For the US:
● See National Electrical Code (NEC), National Electrical Equipment Man‐
ufacturers Association (NEMA) and regional building codes.
The national regulations have to be observed!
The permanent magnetic brake is no safety brake. This means, a torque re‐
duction by non-influenceable disturbance factors can occur (see EN 954; ISO
13849-1; ISO 13849-2 or Information Sheet No. 005 "Gravity loaded axes
(vertical axes)").
Particular attention has to be paid to this:
● Corrosion on the friction surfaces as well as vapors, exhalations and
sediments reduce the braking effect.
● Lubricants must not get onto the friction surface.
● Over-voltages and excessively high temperatures can permanently
weaken the permanent magnets and thus render the holding brake un‐
usable.
If the air gap between armature and pole increases due to wear, the function
of the holding brake is no longer guaranteed.
Brakes are either electrically clamping or electrically releasing. Since there
are functional differences between main spindle and servo axes, different
brakes should be used for these axes.
t
1 1
24
U [V]
N
0
① Electrically clamping brake
② Electrically releasing brake
t Holding brake connection time, clamping delay
1
t Holding brake disconnection time, release delay
2
Fig. 9-9: Holding brake wiring diagram
The electrically clamping holding brake serves as a locking element for the
main spindle at standstill and deactivated drive enable, e.g., when the tool is
changed without closed position control loop.
MAD / MAF Asynchronous Housing Motors
t
2
2
24
U [V]
N
0
t
t2 t1
t