KEB COMBIVERT F5-A, Applications Manual, Page: 446 / 552

Page 7.15 - 14 COMBIVERT F5-A, -E, -H © KEB, 2012-10
Special functions
7.15.5.2 Monitoring of the brake control
Pn.43 "min. load brake control"
Further brake control can be activated with Pn.43 "min. load brake control".
For the monitoring of the utilization acceptance through the inverter a minimal utilization level can be adjusted
in this parameter.
If the brake is to be opened on start at the end of the pre-magnetising time (Pn.35), the load factor may not be
smaller than the adjusted level. Otherwise error E. br is triggered. Reaching the hardware current limit during
this phase also triggers error E.br. The current is monitored only at this time (directly before the opening of the
brake).
The monitoring is deactivated when Pn.43 is set to 0.
Pn.42 "brake check input selection"
The brake must always be closed between the end of the brake closing time (Pn.40) and the beginning of the
break release time (Pn.36). E.br is triggered if the input becomes (or is) active during this phase.
Similarly, from the end of the brake opening period (Pn.36) to the end of the brake delay time (Pn.39), the brake
must always remain ventilated. If the input becomes (or is) inactive in this phase, E.br is also triggered.
With this input, e.g., a protection monitoring could be executed.
7.15.5.3 Sequence of the brake control
The sequence of the brake control is defined by five times, two for the opening and three for the closing of the
brake.
open brake
The opening of the brake is started when the control release is closed and the command to start the drive is
received.
In vector controlled operation, this is the activation of the direction of rotation, the setpoint speed has no effect.
That means: the brake is opened as well on setting the speed setpoint value = 0.
During positioning, the opening of the brake is triggered, e.g., by a "Start positioning" or a "Start approach to
reference point" command
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Pn.35: premagnetising time
The pre-magnetisation time serves to build up a holding torque to minimise the "stall out" of the drive
during ventilation of the brake.
The adjustment of this time and the brake control start ref. (Pn.37) is depending on the mode
(v/f-characteristic controlled, vector controlled, etc.) and is described in the items 7.15.5.4 and 7.15.5.5.
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Pn.36: Brake release time
With begin of the brake release time, the signal to open the brake is issued.
During brake release time when the brake is mechanically released, the speed set value (ru.01) is not yet
stored, but the brake control starting value (Pn.37) is still maintained. For vector controlled systems, Pn.37
must contain the value 0 rpm for synchronous as well as for asynchronous motors.
close brake
The closing of the brake is triggered by disabling the direction of rotation (speed control), reaching of the target
position (positioning), or switching off the modulation (opening of the control release or error).