Danfoss VLT 3006 Product Manual page 99

Parameter description
300
Brake option
(Brake option)
301
Start frequency
(Start freq.)
302
Start delay
(Start delay)
303
High starting torque
(HI start torq)
304
Mains failure
(Power fail)
305
Flying start
(Flying start)
98
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Value:
Not applied (not applied)
Applied (applied)
Value:
0.0 - 10 Hz
Value:
0.0 - 1 sec.
Value:
0.0 - 1 sec.
Value:
Uncontrolled stop (stop)
Ramp-down 1 (ramp stop)
Ramp-down 2 (alt. ramp st.)
Value:
Disable (disable)
OK - same direction (same direct)
OK - both directions (both direct)
DC-brake before start
(DC-brake 1st)
= Factory setting. Text in ( ) = Display text.
The figures in [ ] are used in bus communication.
®
MG.30.A7.02 - VLT is a registered Danfoss trademark
The parameter is used with the brake op-
tion and brake resistor. A higher interme-
[0]
diate circuit voltage during braking is
[1]
permitted.
Insert the start frequency at which the
motor is to start (can e.g. be used on raise/
0.0
lower application).
The VLT ® frequency converter will start on
the start frequency (parameter 301) and
0.0
start ramping up after the start delay time
is over.
Set the time needed for high starting
torque. A high initial torque means that a
0.0
current of 2 x the current limit in parameter
209 is permitted. However, the current is
limited by the inverter's protection limit.
Function:
Select one of the 3 ramp-down functions to
[0]
prolong the ride through time at mains fail-
[1]
[2] ure. The effect will depend on the load and
the mains voltage before failure.
Description of choices:
UNCONTROLLED STOP: The motor will
continue running at the selected speed un-
til control trips.
RAMP-DOWN 1: The motor will start to
ramp down imme-diately (parameter 216)
until control trips.
RAMP-DOWN 2: The motor will start to
ramp down immediately (parameter 218).
Reliable regenerative operation of the
frequency converter over the ramp down 1
or 2 function requires a large inertia force
and negligible operational motor load on
the frequency converter.
Function:
The parameter is used when the VLT
[0]
frequency converter is cut in on a rotating
[1]
motor (e.g. after current has been
[2]
disconnected). This function is optimal at a
4.5 kHz switching frequency. The function
[3]
may not work properly when using another
switching frequency.
Description of choices:
OK - same direction: Chosen if the motor
can only rotate in same direction on cut-in.
OK - both directions: Chosen when the
motor can only rotate in both directions on
cut-in.
Stop - before start: Selected if the motor
is to be stopped using d.c brake before
the motor is ramped up to the desired
speed. The D.C. brake time must be set in
parameter 306. The selected function is
activated in accordance with the diagram
on p. 72.
3.. Functions and timers
®