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Start/stop functions and timers, group 3..
This parameter group includes special start/stop
functions, e.g. how to catch a spinning motor. It is
also possible to programme a timer for the relay
outputs.
301 Start frequency (START FREQ)
Value:
0.0 - 10 Hz
Function:
It is possible to define an output frequency at which
the motor is to start.
Description of choice:
Programme the start frequency at which the motor is
to start.
302 Delayed start (START DELAY)
Value:
0.0 - 1 sec.
Function:
VLT 3500 HVAC starts at the start frequency (parame-
ter 301) and begins to ramp up when the start delay
has ended.
Description of choice:
Programme the desired time delay before VLT 3500
HVAC starts to ramp up.
303 High starting torque (HI START TORQ.)
Value:
0.0 - 1 sec.
Function:
A high starting torque means that a current approx. 2
x the current limit of parameter 209 is permitted.
However, the current is limited by the protection limit
of the inverter.
Description of choice:
Insert the time required to give as high a starting tor-
que as desired.
304 Mains failure (POWER FAIL)
Value:
Uncontrolled stop (NORM PWR DWN)
Ramp down 1 (RAMP DOWN)
Ramp down 2 (ALT. RAMP DOWN)
= factory setting. Text in ( ) = display text. Figures in [ ] are used when communicating with the bus.
56
VLT
Function:
Select one of the 3 ramp-down functions to extend
the overrun time in case of mains failure. The effect
will depend on the load and the mains voltage before
the failure.
Description of choice:
Uncontrolled stop [0]:
The motor continues to run at the selected speed un-
0.0 Hz
til the controls cut out.
Ramp down 1 [1]:
The motor begins to ramp down immediately (para-
meter 216) until the controls cut out.
Ramp down 2 [2]:
The motor begins to ramp down immediately (para-
meter 218). If the ramp-down time is short, a regene-
rative effect may keep up the DC voltage, which
means that it takes longer before the controls cut out.
0.0 sec.
305 Cutting in on rotating motor
(FLYING START)
Value:
Disable (NO FLY START)
OK - same direction (SAME DIRECT)
OK - both directions (BOTH DIRECT)
Stop before start (CD-BRAKE @STAR)
Function:
This parameter is used when VLT 3500 HVAC cuts in
on a rotating motor (e.g. after a power failure).
0.0 sec.
Description of choice:
OK - same direction [1]:
Chosen if the motor is only able to rotate in the same
direction when cutting in.
OK - both directions [2]:
Chosen if the motor is able to rotate in both directions
when cutting in.
Stop before start [3]:
Chosen if the motor is to be stopped by means of
DC-braking, before the motor is ramped up to the
desired speed. The DC braking time is to be set in
parameter 306.
The selected function is activated in accordance with
[0]
the diagram on next page.
[1]
[2]
®
3500 HVAC
MG.35.B1.02 – VLT is a registered Danfoss trademark
[0]
[1]
[2]
[3]
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