![background image](http://html.mh-extra.com/html/danfoss/fc-300/fc-300_design-manual_507599010.webp)
Thermistor:
A temperature-dependent resistor placed where the temperature is to be monitored (adjustable frequency drive or motor).
THD
Total Harmonic Distortion state the total harmonic contribution.
Trip
A state entered in fault situations, e.g., if the adjustable frequency drive is subject to an overtemperature or when the adjustable frequency drive is
protecting the motor, process or mechanism. Restart is prevented until the cause of the 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 adjustable frequency drive is protecting itself and requiring physical intervention, e.g., if the adjustable
frequency drive is subject to a short circuit on the output. A locked trip can only be canceled by cutting off line power, removing the cause of the fault,
and reconnecting the adjustable frequency drive. Restart is prevented until 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.
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.
60° AVM
Switching pattern called 60° Asynchronous Vector Modulation (par. 14-00
Switching Pattern
).
Power Factor
The power factor is the relation between I
1
and I
RMS
.
Power
factor
=
3
x
U
x
I
1
cos
ϕ
3
x
U
x
IRMS
The power factor for 3-phase control:
=
I
1
x
cos
ϕ
1
IRMS
=
I
1
IRMS
since
cos
ϕ
1 = 1
The power factor indicates to which extent the adjustable frequency drive
imposes a load on the line power supply.
The lower the power factor, the higher the I
RMS
for the same kW per-
formance.
IRMS
=
I
1
2 +
I
5
2 +
I
7
2 + .. +
In
2
In addition, a high power factor indicates that the different harmonic currents are low.
All Danfoss adjustable frequency drives have built-in DC coils in the DC link to increase the power factor and to reduce the THD on the line power supply.
1 How to Read this Design Guide
FC 300 Design Guide
1-6
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
1