VSP
Variable-speed pump
VT
Variable torque
VVC
+
Voltage vector control plus
Table 14.1 Abbreviations and Symbols
14.2 Definitions
Brake resistor
The brake resistor is a module capable of absorbing the
brake power generated in regenerative braking. This
regenerative brake power increases the DC-link voltage
and a brake chopper ensures that the power is transmitted
to the brake resistor.
Break-away torque
n
s
= 2 × par . 1 − 23 × 60 s
par . 1 − 39
175ZA078.10
Pull-out
RPM
Torque
Illustration 14.1 Break-away Torque Chart
Coast
The motor shaft is in free mode. No torque on the motor.
CT characteristics
Constant torque characteristics used for all applications
such as conveyor belts, displacement pumps, and cranes.
Initializing
If initializing is carried out (
parameter 14-22 Operation
Mode
), the drive returns to the default setting.
Intermittent duty cycle
An intermittent duty rating refers to a sequence of duty
cycles. Each cycle consists of an on-load and an off-load
period. The operation can be either periodic duty or non-
periodic duty.
Power factor
The true power factor (lambda) takes all the harmonics
into consideration and is always smaller than the power
factor (cos phi) that only considers the 1
st
harmonics of
current and voltage.
cosϕ = P kW
P kVA =
Uλ x Iλ x cosϕ
Uλ x Iλ
Cos phi is also known as displacement power factor.
Both lambda and cos phi are stated for Danfoss VLT
®
drives in
The power factor indicates to which extent the drive
imposes a load on the mains. The lower the power factor,
the higher the I
RMS
for the same kW performance. In
addition, a high-power factor indicates that the harmonic
currents are low.
All Danfoss drives have built-in DC coils in the DC link to
have a high-power factor and reduce the THD on the main
supply.
Pulse input/incremental encoder
An external digital sensor used for feedback information of
motor speed and direction. Encoders are used for high-
speed accuracy feedback and in high dynamic applications.
Set-up
Save parameter settings in 4 set-ups. Change between the
4 parameter set-ups and edit 1 set-up while another set-up
is active.
Slip compensation
The drive compensates for the motor slip by giving the
frequency a supplement that follows the measured motor
load, keeping the motor speed almost constant.
Smart logic control (SLC)
The SLC is a sequence of user-defined actions executed
when the associated user-defined events are evaluated as
true by the SLC. (
Parameter group 13-** Smart Logic
).
FC standard bus
Includes RS485 bus with FC protocol or MC protocol. See
parameter 8-30 Protocol
.
Thermistor
A temperature-dependent resistor placed where the
temperature is to be monitored (drive or motor).
Trip
A state entered in fault situations, such as when the drive
is subject to an overtemperature or when it protects the
motor, process, or mechanism. Restart is prevented until
the cause of the fault has disappeared and the trip state is
canceled.
Trip lock
A state entered in fault situations when the drive is
protecting itself and requires physical intervention. A
locked trip can only be canceled by cutting off mains,
removing the cause of the fault, and reconnecting the
drive. Restart is prevented until the trip state is canceled
by activating reset.
VT characteristics
Variable torque characteristics for pumps and fans.
Appendix
VLT® AutomationDrive FC 302
202
Danfoss A/S © 01/2018 All rights reserved.
MG38C202
14
14
