Firmware
≤
11.00 - DMS 8.0 EN - 10/2011
L
229
8400 StateLine C | Reference manual
Motor control (MCTRL)
Braking operation/brake energy management
Operating mode of the inverter motor brake
The ramp function generator is stopped during acceleration. The speed set in
C00987
is
added to the speed setpoint by means of a hysteresis-type 2-point DC bus voltage
controller, whereby the sign of the current actual speed is taken into account. In addition,
the ramp function generator is stopped during overvoltage.
If the DC bus voltage falls below a defined DC bus voltage potential of the hysteresis
controller, the added speed is subtracted again and the ramp function generator is
activated again.
The energy is converted into heat in the motor due to alternating instances of acceleration
and deceleration as a result of this switching operation.
[5-27] Signal flow of the "Inverter motor brake" function
In case of an asynchronous motor, the additive speed setpoint (
C00987
) should be 1 … 4
times the slip of the machine:
[5-28] Formula for calculating the additive speed setpoint for an asynchronous motor
In case of a synchronous motor, the additive speed setpoint (
C00987
) should be
5 … 20 % of the rated machine speed.
n
DC-bus voltage
o
Speed setpoint for motor control
0
1
QSP
nSpeedSetValue_a
C00173
C00174
C00987
C00105
C00988
C00050
C00909/1
C00909/2
nEffSpeedSetValue_a
bLimSpeedSetVal
QSP ramp
Inverter
motor brake
p = number of pole pairs
n
Rat
= Rated speed of the motor
f
Rat
= Rated frequency of the motor
n
Sync
= Synchronous speed of the motor
C00987 [rpm]
1 ... 4 n
Sync
[rpm] n
Rated
[rpm]
–
(
)
⋅
=
n
Sync
[rpm]
f
Rated
[Hz] 60
⋅
p
------------------------------------
=
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