fault has disappeared and the trip state is canceled by
activating reset or, in some cases, by being programmed
to reset automatically. Trip may not be used for personal
safety.
Trip Locked
A state entered in fault situations when the frequency
converter is protecting itself and requiring physical
intervention, e.g. if the frequency converter is subject to a
short circuit on the output. A locked trip can only be
canceled by cutting off mains, removing the cause of the
fault, and reconnecting the frequency converter. Restart is
prevented until the trip state is canceled by activating
reset or, in some cases, by being programmed to reset
automatically. Trip locked may not be used for personal
safety.
VT Characteristics
Variable torque characteristics used for pumps and fans.
VVC
plus
If compared with standard voltage/frequency ratio control,
Voltage Vector Control (VVC
plus
) improves the dynamics
and the stability, both when the speed reference is
changed and in relation to the load torque.
1.1.6 Power Factor
The power factor is the relation between I
1
and I
RMS
.
Power factor =
3 ×
U × I1 × COSϕ
3 ×
U × IRMS
The power factor for 3-phase control:
=
I1 × cosϕ1
IRMS
=
I1
IRMS
since cosϕ1 = 1
The power factor indicates to which extent the frequency
converter imposes a load on the mains supply.
The lower the power factor, the higher the I
RMS
for the
same kW performance.
IRMS = I1
2 + I
5
2 + I
7
2 + . . + In2
In addition, a high-power factor indicates that the different
harmonic currents are low.
How to Read this Design Gui...
VLT Micro Drive Design Guide
MG02K102 - VLT
®
is a registered Danfoss trademark
9
1
1