Technical data

Drive functions
7.3 Function modules
Function Manual
214 Function Manual, 06/2012, 6SL3097-4AB10-0BP4
7.3.4.4 Examples
Starting against applied brake
When the device is switched on, the setpoint is enabled immediately (if other enable signals
are issued), even if the brake has not yet been released (p1152 = 1). The factory setting
p1152 = r0899.15 must be disconnected here. The drive first generates torque against the
applied brake. The brake is not released until the motor torque or motor current (p1220) has
exceeded braking threshold 1 (p1221).
This configuration is used, for example, when the drive is connected to a belt that is under
tension (loop accumulator in the steel industry).
Emergency brake
If emergency braking is required, electrical and mechanical braking is to take place
simultaneously. This can be achieved if OFF3 is used as a tripping signal for emergency
braking:
p1219[0] = r0898.2 (OFF3 to "apply brake immediately").
The OFF3 ramp (p1135) should be set to 0 seconds so that the converter does not work
against the brakes. Regenerative energy may accumulate, and this must be either fed back
into the supply system or converted into heat using a braking resistor.
This is often used, for example, in calendar stacks, cutting tools, running gears, and presses.
Operating brake for crane drives
For cranes with a manual control, it is important that the drive immediately response when
the control lever is moved (master switch). The drive is powered-up using the on command
(p0840) (the pulses are enabled). Speed setpoint (p1142) and speed controller (p0856) are
inhibited. The motor is magnetized. The magnetization time generally applicable for three-
phase motors (1-2 seconds) is therefore eliminated.
Now, there is only the brake opening time that is applicable as delay between moving the
master switch and the motor rotating. If the master switch is moved (deflected), then there is
a "setpoint enable from the control" (bit interconnected with p1142, r1229.3, p1224.0). The
speed controller is immediately enabled - the speed setpoint is enabled after the brake
opening time (p1216). When the master switch is in the zero position, the speed setpoint is
inhibited - the drive is ramp-down using the ramp function generator. The brake closes once
the standstill limit (p1226) has been fallen below. After the brake closing time (p1217), the
speed controller is inhibited (the motor is no longer generating any force). The extended
brake control is used with the modifications described below.