Lenze MDFQA Operating Instructions - Manual (Page 24)

Mechanical installation
Holding brake (option)
Permanent magnet holding brakes
5
EN
24 Lenze ¯ BA 33.0006 ¯ 3.0
5.4.1 Permanent magnet holding brakes
These brakes are used as holding brakes and serve to hold the axes without backlash at
standstill or in the deenergised state.
When activating the brake, it must be ensured that the brake is released or engaged at
zero speed to avoid unnecessary and rapid wear of the brake.
When used solely as holding brakes, the brakes are virtually wear free on their friction
surfaces. If the max. permissible switching energy per emergency stop (see catalogue)
is not exceeded, at least 2000 emergency stop functions from a speed of 3000 rpm are
possible.
W + ½ @ J
ges
@ w 2
W [J] Energy
J
tot
[kgm 2 ] Total moment of inertia
w [ 1 /
s
] Angular velocity w=2p n /
60
, n= speed [rpm]
The holding torques specified in the catalogue only apply when the motor is at
standstill. In the case of a slipping brake, the dynamic braking torque always applies
which depends on the speed.
(
Stop!
The holding brake is only designed for a limited number of emergency
stops. Utilisation as a working brake, e.g. to decelerate a load, is not
permissible.
)
Note!
The brakes are maintenance−free and cannot be adjusted. In the event of
wear, e.g. through emergency stops, the brakes must be replaced.
These brakes operate according to the closed−circuit principle, i.e. the brake is closed in
the deenergised state.
Brakes with a rated voltage of DC 24 V are designed for smoothed DC voltages with a
ripple of <1 %. It must be ensured that the connector on the motor side is supplied with
the minimum voltage of DC 24 V −10 %. If necessary, the voltage drop in the cable should
also be considered. If the maximum voltage DC 24 V + 5 % is exceeded, the brake can
close again. Supplying the brake with bridge−rectified DC voltage (bridge rectifier
without additional smoothing) or a DC voltage with a ripple of >1 % can lead to a
malfunctioning of the brake or an increase in the engagement and disengagement
times.
Brakes with a rated voltage of DC 205 V are designed for bridge−rectified DC voltage, i.e.
for supply via a bridge rectifier from the 230 V mains (half−wave rectifiers are not
permissible). Supplying the brake with smoothed DC voltage can lead to
malfunctioning or an increase in the engagement and disengagement times. With
regard to the minimum and maximum voltages, the same conditions apply as for brakes
with 24 V, i.e. the permissible voltage tolerance is 205 V DC +5 %, −10 %.