Danfoss VLT AQUA Drive FC 202 Design Guide

-
PTC thermistor input on VLT
®
PTC
Tthermistor Card MCB 112 (ATEX
approved).
•
Mechanical thermal switch (Klixon type) on a DI.
•
Via the built-in electronic thermal relay (ETR) for
asynchronous motors.
ETR calculates motor temperature by measuring current,
frequency, and operating time. The adjustable frequency
drive displays the thermal load on the motor in percentage
and can issue a warning at a programmable overload
setpoint.
Programmable options at the overload allow the adjustable
frequency drive to stop the motor, reduce output, or
ignore the condition. Even at low speeds, the adjustable
frequency drive meets I2t Class 20 electronic motor
overload standards.
1.21.0 1.4
30
10
20
100
60
40
50
1.81.6 2.0
2000
500
200
400
300
1000
600
t [s]
175ZA052.11
fOUT = 0.2 x f M,N
fOUT = 2 x f M,N
fOUT = 1 x f M,N
IMN
IM
Figure 2.18 ETR Characteristics
The X-axis in Figure 2.18 shows the ratio between I
motor
and
I
motor
nominal. The Y-axis shows the time in seconds before
the ETR cuts
o and trips the adjustable frequency drive.
The curves show the characteristic nominal speed, at twice
the nominal speed and at 0.2 x the nominal speed.
At lower speed, the ETR cuts o at lower heat due to less
cooling of the motor. In that way, the motor is protected
from being overheated even at low speed. The ETR feature
calculates the motor temperature based on actual current
and speed. The calculated temperature is visible as a
readout parameter in 16-18 Motor Thermal.
2.6.3
Line Drop-out
During a line drop-out, the adjustable frequency drive
keeps running until the intermediate circuit voltage drops
below the minimum stop level, which is typically 15%
below the lowest rated supply voltage. The AC line voltage
before the drop-out and the motor load determines how
long it takes for the adjustable frequency drive to coast.
The adjustable frequency drive can be congured
(14-10 Line Failure) to dierent types of behavior during
line drop-out,
•
Trip Lock once the DC link is exhausted.
•
Coast with ying start whenever line power
return (1-73 Flying Start).
•
Kinetic backup.
•
Controlled ramp-down.
Flying start
This selection makes it possible to catch a motor that is
spinning freely due to a line drop-out. This option is
relevant for centrifuges and fans.
Kinetic backup
This selection ensures that the adjustable frequency drive
runs as long as there is energy in the system. For short line
power drop-out, the operation is restored upon line return,
without bringing the application to a stop or losing control
at any time. Several variants of kinetic backup can be
selected.
Congure the behavior of the adjustable frequency drive
at line drop-out, in 14-10 Line Failure and 1-73 Flying Start.
2.6.4
Built-in PID Controllers
The four built-in proportional, integral, derivative (PID)
controllers eliminate the need for auxiliary control devices.
One of the PID controllers maintains constant control of
closed-loop systems where regulated pressure, ow,
temperature, or other system requirements must be
maintained. The adjustable frequency drive can provide
self-reliant control of the motor speed in response to
feedback signals from remote sensors. The adjustable
frequency drive accommodates two feedback signals from
two dierent devices. This feature allows regulating a
system with dierent feedback requirements. The
adjustable frequency drive makes control decisions by
comparing the two signals to optimize system
performance.
Product Overview
VLT
®
AQUA Drive FC 202
30 Danfoss A/S © 09/2014 All rights reserved. MG20N622
22

Danfoss VLT AQUA Drive FC 202 Specifications

General

Brand	Danfoss
Model	VLT AQUA Drive FC 202
Category	DC Drives
Language	English