54
VLT
®
3500 HVAC
MG.35.B1.02 – VLT is a registered Danfoss trademark
223 Frequency bypass bandwidth (BYPASS B.WIDTH)
Value:
0 - 100%
★
0 %
Function: (Parameter 219-223)
Some systems require that certain output frequencies
are avoided which lead to resonance problems in the
installation.
In parameters 219-222 these output frequencies can
be programmed to be bypassed (frequency bypass).
In parameter 223, a bandwidth on either side of these
frequencies can be defined.
Description of choice: (Parameter 219-223)
Enter the frequencies to be avoided and the band-
width as a percentage of the keyed-in frequencies.
The bypass band is the bypass fre/- the
bandwidth selected.
224 Carrier frequency (CARRIER FREQ.)
Value:
2.0 - 14.0 kHz
★
4.5 kHz
Function:
The set value determines the carrier frequency of the
inverter. Changing the switching frequency will mini-
mise any acoustic noise from the motor. Certain types
may not operate at a higher switching frequency than
4.5 kHz (VLT 3575-3800 and VLT 3542- 3562 (230 V)).
Description of choice:
When the motor is running, the switching frequency is
adjusted in parameter 224 to find the switching fre-
quency at which the noise from the motor is reduced
to the greatest possible extent.
NB!:
NB!:
NB!:
NB!:
NB!:
Switching frequencies higher than 4.5 kHz lead
to automatic derating.
217 Alternative ramp-up time (ALT. UP RAMP)
Value:
0.00 - 3600 secs.
★
depends on unit
Function:
This alternative ramp time is activated when the jog
function is activated via terminal 29 (parameter 405)
or RS 485; no other start signal must have been given
(e.g. terminal 18 (parameter 402)).
Description of choice:
The desired alternative ramp-up time is programmed.
218 Alternative ramp-down time (ALT. DOWN RAMP)
Value:
0.00 - 3600 secs.
★
depends on unit
Function:
This alternative ramp time is activated when a quick-
stop is used via terminal 27, parameter 404 or via the
serial bus (RS 485).
Description of choice:
The desired alternative ramp-down time is programmed.
219 Frequency bypass 1 (FREQ 1 BYPASS)
Value:
0 - 120 Hz
★
120 Hz
220 Frequency bypass 2 (FREQ 2 BYPASS)
Value:
0 - 120 Hz
★
120 Hz
221 Frequency bypass 3 (FREQ 3 BYPASS)
Value:
0 - 120 Hz
★
120 Hz
222 Frequency bypass 4 (FREQ 4 BYPASS)
Value:
0 - 120 Hz
★
120 Hz
★
= factory setting. Text in ( ) = display text. Figures in [ ] are used when communicating with the bus.
3.6 Parameter gr
oup 2
Description of parameter 219 - 222 see parameter
223.
