6
Operating modes and limit values
Special application
Operating Instructions – EDR..71 – 315, EDRN63 – 315
115
6.7.1
Calculating the motor terminal voltage
The calculation of the motor terminal voltage is an important component of project
planning. The results must be considered during startup and corrected, if necessary,
to prevent excessive heating of the motor.
U [V]
Line choke
Line filter
Inverter (FI)
Output filter
Motor
Uline, observe tolerances
Δ UND
Δ UNF
UE_FI = Uline – Δ UND – Δ UNF
UA_FI = 0.925 x UE_FI
Δ UHF
Δ Upermitted
UMotor terminal voltage = UA_FI – Δ UHF – Δ Upermitted
36028798477033099
U
line
Line voltage
U
I_FI
Inverter input voltage in V
Δ U
Zul
Voltage drop at the motor cable in V
U
O_FI
Inverter output voltage in V
Δ U
ND
Voltage drop at the line choke in V
Δ U
HF
Voltage drop at the output filter in V
Δ U
NF
Voltage drop at the line filter in V
For inverter operation, the motor voltage is calculated as follows:
V
V
V
V
V
V
Motor
Line
LineFilter Choke
FI
Outp Filter
Cabl
=
−
+
+
+
(
/
.
∆
∆
∆
∆
e
e
)
1495196939
25896334/EN – 06/2019