Specifications

2.8 Control Structures
2.8.1 Control Principle
Inrush
R inr
Load sharing -
Load sharing +
LC Filter -
(5A)
LC Filter +
(5A)
Brake
Resistor
130BA193.14
M
L2 92
L1 91
L3 93
89(+)
88(-)
R+
82
R-
81
U 96
V 97
W 98
P 14-50 R Filter
Illustration 2.23 Control Structures
The frequency converter is a high-performance unit for demanding applications. It can handle various kinds of motor
control principles such as U/f special motor mode and VVC
plus
and can handle normal squirrel cage asynchronous motors.
Short circuit behavior on this frequency converter depends on the 3 current transducers in the motor phases.
Select between open loop and closed loop in 1-00 Configuration Mode.
2.8.2
Control Structure Open Loop
130BB153.10
100%
0%
-100%
100%
P 3-13
Reference
site
Local
reference
scaled to
RPM or Hz
Auto mode
Hand mode
LCP Hand on,
o and auto
on keys
Linked to hand/auto
Local
Remote
Reference
Ramp
P 4-10
Motor speed
direction
To motor
control
Reference
handling
Remote
reference
P 4-13
Motor speed
high limit [RPM]
P 4-14
Motor speed
high limit [Hz]
P 4-11
Motor speed
low limit [RPM]
P 4-12
Motor speed
low limit [Hz]
P 3-4* Ramp 1
P 3-5* Ramp 2
Illustration 2.24 Open Loop Structure
In the configuration shown in Illustration 2.24, 1-00 Configuration Mode is set to [0] Open loop. The resulting reference from
the reference handling system or the local reference is received and fed through the ramp limitation and speed limitation
before being sent to the motor control.
The output from the motor control is then limited by the maximum frequency limit.
Introduction to VLT® HVAC D...
Design Guide
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