Lenze EVS 9300 series - Page 279

Function library
Function blocks
9.2.41 Mains failure control (MFAIL)
9-153
L
EDSVS9332S-D11 EN 3.0
Fine setting
Repeat the following steps several times.
1. Obtain a very low final speed before the controller reaches the undervoltage threshold LU:
– Increase the proportional gain MFAIL V
p
(C0980).
– Reduce the adjustment time MFAIL T
n
(C0981).
2. Avoid activation of the brake unit or the overvoltage threshold:
– Increase the adjustment time MFAIL T
n
(C0981) until the characteristic in Fig. 9-103 is almost
reached.
– Reduce additionally the setpoint of the DC bus voltage at the input MFAIL-DC-SET (in the
example C0472/19), if necessary.
3. Increase of the deceleration time or reduction of the brake torque (see Fig. 9-104) is only
possible with restrictions:
– An increase of the acceleration time MFAIL T
ir
(C0982) reduces the initial brake torque and
increases the deceleration time.
– An increase of the adjustment time MFAIL T
n
(C0981) reduces the brake torque and
increases the deceleration time. If the adjustment times under C0981 are too long, the
controller reaches the LU threshold before zero speed is reached. The drive is therefore no
longer controlled.
4. Re-establish signal connections which may be used, to the outputs of the controller (terminals
X6).
Note!
All settings must be stored non-volatilely in a parameter set under C0003.
t
U G
t 1
t 2
t
n
0
0
C M P 2 - O U T
M F A I L - D C - S E T
t 3
O
p e r a t i n g t h r e s h o l d
S w i t c h - o f f t h r e s h o l d O U
S w i t c h - o n t h r e s h o l d b r a k e u n i t
S w i t c h - o f f t h r e s h o l d L U
Fig. 9-104 Schematic with different brake torques
t = t1 Mains failure
t = t2 Zero speed with higher brake torque (short adjustment time)
t = t3 Drive reaches the LU switch-off threshold with lower brake torque (high adjustment time),
without reaching zero speed
t > t3 Drive is no longer controlled (is braked by friction)