Lenze EVF9333−xV - Manual (Page 452)

Troubleshooting and fault elimination
Fault elimination
Controller in clamp operation
9
9.4
9.4.2
l
9.4−2 EDSVF9333V EN 6.2−04/2012
9.4.2 Controller in clamp operation
The clamp operation is a permissible operating mode. But since, however,
pulse inhibit is set again and again, the controller cannot provide the
optimum power.
If the output power is optimal, the output current mainly is right below the
clamp threshold.
9300vec110
Fig. 9.4−1 Output current when starting a motor with high load (shown with the
oscilloscope in GDC)
0
Clamp threshold
1 Output current
Function
1. When the output current reaches 2.25 × I
r
, a software clamp is
activated.
2. The controller sets pulse inhibit for a short time. The motor current
decreases as a function of the inductance in the motor circuit.
– An internal counter is increased by the value one.
3. After max. 250
ms the pulse inhibit is deactivated.
4. If a software clamp reoccurs within 2 s, the internal counter is again
increased by the value one. Otherwise the counter is set to zero.
– If the counter reaches the value 4300, OC3 (TRIP) is activated.