DEMAG ZBA Assembly Instructions Manual page 20

• Connection in the DC circuit:
• Connection in the AC circuit:
• Connection in the motor circuit:
1) Definition: The brake release time is the period which elapses until the full motor acceleration torque is attained.
20
The coil circuit is interrupted when the brake module contact opens at the relevant
terminal. The magnetic field rapidly decreases and the brake torque rapidly
rises. The rectifiers are protected against overvoltage at the switching contact by
varistors.
Interruption of the DC circuit between the module and the coil connections is not
permitted.
When the brake voltage is switched off, i.e. on the supply side before the rectifier,
an inductive coil current continues to flow through the rectifier diodes for a short
time. The magnet field decreases more slowly. The braking operation begins more
smoothly.
This connection type is not suitable for hoist drives.
The rectifier is connected direct to the motor terminals. When the motor is switched
off, the residual motor voltage results in significantly longer switch-off times
compared to switch-off in the AC circuit.
Unless provided with additional switch-off in the DC circuit using a contact or
by the SE current relay, this type of connection is not suitable for drives with
overhauling loads, e.g. hoists, and may not be used in these applications.
IMPORTANT. Unless provided with additional switch-off in the DC circuit using a
i
contact or by the SE current relay, this type of connection is not suitable for drives
with overhauling loads, e.g. hoists, and may not be used in these applications.
Different excitation times result according to the connection. These times depend
on the one hand on the selected brake torque and, more decisively, on the brake
connection.