128 Functional description CG Drives & Automation 01-7491-01r0
11.3.4 Mechanical brake control
The four brake-related menus [33C] to [33F] can be used to
control mechanical brakes.
Support is included for a Brake Acknowledge signal via a
digital input. It is monitored using a brake fault time
parameter. Additional output and trip/warning signals are
also included. The acknowledge signal is either connected
from the brake contactor or from a proximity switch on the
brake.
Brake not released - Brake Fault trip
During start and running the brake acknowledge signal is
compared to the actual brake output signal and if no
acknowledge, i.e. brake not released, while brake output is
high for the Brake Fault time [33H], then a Brake trip is
generated.
Brake not engaged - Brake Warning
and continued operation (keep
torque)
The brake acknowledge signal is compared to the actual
brake output signal at stop. If acknowledge is still active, i.e.
brake not engaged, while brake output is low for the Brake
Engage time [33E] then a Brake warning is generated and
the torque is kept, i.e. prolonging normal brake engage
mode, until brake closes or an emergency action is needed
by the operator, such as setting down the load.
Brake Release Time [33C]
The Brake Release Time sets the time the AC drive delays
before ramping up to whatever final reference value is
selected. During this time a predefined speed can be
generated to hold the load where after the mechanical brake
finally releases. This speed can be selected at Release Speed,
[33D]. Immediate after the brake release time expiration the
brake lift signal is set. The user can set a digital output or
relay to the function Brake. This output or relay can control
the mechanical brake.
Fig. 107 shows the relation between the four Brake
functions.
• Brake Release Time [33C]
• Release Speed [33D]
• Brake Engage Time [33E]
• Brake Wait Time [33F]
The correct time setting depends on the maximum load and
the properties of the mechanical brake. During the brake
release time it is possible to apply extra holding torque by
setting a release speed reference with the function release
speed [33D].
33C Brk Release
Default: 0.00 s
Range: 0.00–3.00 s
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