Siemens MICROMASTER 420 - Current Limiting (Imax Controller)

3 Functions Issue 07/04
MICROMASTER 420 Operating Instructions
150 6SE6400-5AA00-0BP0
3.21.1.5 Current limiting (Imax controller)
Parameter range: P1340 – P1344
r0056 bit 13
Warnings A0501
Faults F0001
Function chart number: FP6100
Our drive inverters have, in the V/f characteristic mode, a current limiting controller
(Imax controller, refer to Fig. 3-64). This controller avoids overload conditions. This
controller protects the drive inverter and the motor against continuous overload
conditions by automatically reducing the drive inverter output frequency by f
Imax
(r1343) or the drive inverter output voltage by V
Imax
(r1344). By either reducing the
output frequency or the output voltage, this reduces the load on the drive inverter
and protects against continuous damage.
Imax controller setpoint
+
−
r1343
CO:Imax ctrl Foutp
r1344
CO:Imax ctrl Voutp
Current feedback
r0067
CO: Outp cur limit [A]
r0068
CO: Output current [A]
Motor ovl fact [%]
10.0 ... 400.0 [%]
P0640.D (150.0)
Motor temperatur
Inverter temperatur
i
2
t
inverter
Motor ovl fact [%]
10.0 ... 400.0 [%]
P0640.D (150.0)
Imax ctrl prp gain
0.000 ... 5.499
P1345.D (0.250)
Kp Tn
Kp Tn
Imax ctrl int time
0.000 ... 50.000 [s]
P1346.D (0.300)
Imax ctrl prp gain
0.000 ... 0.499
P1340.D (0.000)
Imax ctrl int time
0.000 ... 50.000 [s]
P1346.D (0.300)
U
I_max
f
I_max
Fig. 3-64 Imax controller
NOTE
A reduction in the frequency only reduces the load if the load decreases at lower
speeds (e.g. square-law torque-speed characteristic of the driven load).