Power-Off Function - KEB COMBIVERT F4-F Applications Manual

Special Functions
6.8.5 Power-Off
Function
Power-Off / Starting voltage
(Pn.17)
Power-Off / Mode (Pn.33)
Braking torque / Emergency
stop (Pn.60)
© KEB Antriebstechnik, 1999
All Rights reserved
The duty of the Power-Off function is the controlled deceleration of the drive until
standstill in case of undervoltage (e.g. due to a power failure). At that the kinetic
energy of the rotating drive is used to support the inverter DC-link voltage. Thus the
inverter remains in operation and the drive can be stopped in a controlled manner.
Especially at parallel-running drives (e.g. in textile machines) the uncontrolled
deceleration of the motors and possible consequences (e.g. thread breakage) can
be avoided with that.
With Pn.17 the Power-Off function is activated and the DC-link voltage is adjusted,
at which the function shall be triggered.
198 Power-Off function disabled (factory setting)
199...800 Manual adjustment of the starting voltage in Volt. For a safe operation
the adjusted starting voltage must be at least 50 V above the UP-level
(UP: 400V-class=360V; 230V-class=210V DC)
The starting voltage adjusted in this way is now constantly compared with the actual
value of the DC-link voltage. If the actual value drops below the setpoint value the
Power-Off function is activated.
Pn.33 defines the behaviour of the drive after the tripping of the Power-Off function
and on reaching 0 Hz.
1 Modulation off
2 Holding torque (factory setting)
In order for the drive to restart the error must be removed and reset must be actuated.
After the tripping of the Power-Off function the drive is decelerated with the torque
adjusted in Pn.60. Independent of the adjusted braking torque the torque limits adjusted
in CS.5/CS.7 cannot be exceeded. Pn.60 applies to every abnormal Stop-function
and is adjustable in the range of 0,0...5 x rated torque (factory setting 29,4 Nm).
Name: Basis
KEB COMBIVERT F4-F
Functional Description
Date
19.05.99
ANTRIEBSTECHNIK
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