Lenze EVF9338−EV - Manual (Page 32)

Troubleshooting and fault elimination
Fault elimination
Controller in clamp operation
4
l
32 EDKVF93−04 EN 2.0
4.4.2 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. 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.