Danfoss VLT AQUA Drive FC 202 Design Manual page 19

Product Features
•
Sine-wave filter is required when
- Long cables (voltage peaks) or increased
mains voltage produce voltages
exceeding the maximum allowable
voltage at motor terminals.
-
Minimum switching frequency of the
drive does not meet the requirement
stated by the motor manufacturer. The
minimum switching frequency of the
drive is shown as the default value in
parameter 14-01 Switching Frequency.
Compatibility of motor and drive
For motors certified according to EN-60079-7, a data list
including limits and rules is supplied by the motor
manufacturer as a data sheet, or on the motor nameplate.
During planning, installation, commissioning, operation,
and service, follow the limits and rules supplied by the
manufacturer for:
•
Minimum switching frequency.
•
Maximum current.
•
Minimum motor frequency.
•
Maximum motor frequency.
Illustration 5.2 shows where the requirements are indicated
on the motor nameplate.
x
1180
CONVERTER SUPPLY
VALID FOR 380 - 415V FWP 50Hz
3 ~ Motor
1
MIN. SWITCHING FREQ. FOR PWM CONV. 3kHz
2
l = 1.5XI t = 10s t = 10min
OL COOL
M,N
3
MIN. FREQ. 5Hz MAX. FREQ. 85 Hz
4
PWM-CONTROL
f [Hz] 5 15
Ix/I 0.4 0.8
M,N
PTC °C DIN 44081/-82
Manufacture xx
1 Minimum switching frequency
2 Maximum current
3 Minimum motor frequency
4 Maximum motor frequency
Illustration 5.2 Motor Nameplate showing Drive Requirements
MG22B102
Design Guide
Ex-e ll T3
25 50 85
1.0 1.0 0.95
EN 60079-0
EN 60079-7
Danfoss A/S © 05/2017 All rights reserved.
When matching drive and motor, Danfoss specifies the
following extra requirements to ensure adequate motor
thermal protection:
•
Do not exceed the maximum allowed ratio
between drive size and motor size. The typical
≤2xI
value is I
VLT, n m,n
•
Consider all voltage drops from drive to motor. If
the motor runs with lower voltage than listed in
the U/f characteristics, current can increase,
triggering an alarm.
For further information, see the application example in
chapter 12 Application Examples.
5.2.5 Mains Drop-out
During a mains drop-out, the drive keeps running until the
DC-link voltage drops below the minimum stop level. The
minimum stop level is typically 15% below the lowest
rated supply voltage. The mains voltage before the drop-
out and the motor load determines how long it takes for
the drive to coast.
The drive can be configured (parameter 14-10 Mains Failure)
to different types of behavior during mains drop-out:
•
Trip Lock once the DC link is exhausted.
•
Coast with flying start whenever mains return
(parameter 1-73 Flying Start).
•
Kinetic back-up.
•
Controlled ramp down.
Flying start
This selection makes it possible to catch a motor that is
spinning freely due to a mains drop-out. This option is
relevant for centrifuges and fans.
Kinetic back-up
This selection ensures that the drive runs as long as there
is energy in the system. For short mains drop-out, the
operation is restored after mains return, without bringing
the application to a stop or losing control at any time.
Several variants of kinetic back-up can be selected.
Configure the behavior of the drive at mains drop-out, in
parameter 14-10 Mains Failure and parameter 1-73 Flying
Start.
5.2.6 Automatic Restart
The drive can be programmed to restart the motor
automatically after a minor trip, such as momentary power
loss or fluctuation. This feature eliminates the need for
manual resetting, and enhances automated operation for
remotely controlled systems. The number of restart
attempts and the duration between attempts can be
limited.
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