Trip; Trip Locked; Vt Characteristics; Power Factor - Danfoss VLT Programming Manual

1 Introduction

Trip

A state entered in fault situations, e.g. if the frequency converter is subject to an over-temperature or when the frequency converter is protecting the
1
motor, process or mechanism. Restart is prevented until the cause of the fault has disappeared and the trip state is cancelled 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 cancelled by cutting off mains, removing the cause of the fault, and reconnecting the
frequency converter. Restart is prevented until the trip state is cancelled 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
reference is changed and in relation to the load torque.
60° AVM
Switching pattern called 60°Asynchronous Vector Modulation (par. 14-00

Power Factor

The power factor is the relation between I
The power factor for 3-phase control:
The power factor indicates to which extent the frequency converter im-
poses a load on the mains supply.
The lower the power factor, the higher the I
formance.
In addition, a high power factor indicates that the different harmonic currents are low.
The frequency converters' built-in DC coils produce a high power factor, which minimizes the imposed load on the mains supply.
10
Switching Pattern
and I .
1 RMS
for the same kW per-
RMS
MG.11.C9.02 - VLT ®
®
VLT HVAC Drive Programming Guide
plus ) improves the dynamics and the stability, both when the speed
).
x U x I cos
3
1
Power factor
=
x U x I RMS
3
I
I x cos
1 ϕ1 1
since cos
= =
I RMS I RMS
2 + 2 + 2 + .. +
I RMS = I I I
1 5 7
is a registered Danfoss trademark
ϕ
ϕ1 = 1
2
I n