1-78 Compressor Start Max Speed [Hz]
Range:
Function:
to minimize the time where the motor is
operated under the minimum speed for the
application. The time without protection from
the Current Limit and Torque Limit must not
exceed the value set in par. 1.79
Compressor
Start Max Time to Trip
or the drive will trip with
an alarm [A18] Start Failed.
When this function is activated to get a fast
start then also par. 1-86
Compressor Min Speed
for Trip
is activated to protect the application
from running below minimum motor speed e.g.
when in current limit.
This function allows high starting torque and
use of a fast starting ramp. To ensure the build-
up of a high torque during the start, various
tricks can be done through clever use of start
delay / start speed / start current.
1-79 Compressor Start Max Time to Trip
Range:
Function:
5.0 s
*
[0.0 - 10.0
s]
The time, from the start signal is given until the
speed exceeds the speed set in par. 1-77 must
not exceed the time set in the parameter or the
drive will trip with an alarm [A18] Start Failed.
Any time set in par. 1-71
Start Delay
for use of a
start function must be executed within the time
limit.
3.3.7 1-8* Stop Adjustments
1-80 Function at Stop
Option:
Function:
Select the frequency converter function
after a stop command or after the speed is
ramped down to the settings in
Speed for Function at Stop [RPM]
[0]
*
Coast
Leaves motor in free mode.
[1]
DC Hold/Motor
Preheat
Energizes motor with a DC holding current
(see
).
[2]
Motor check,
warning
Issues a warning if the motor is not
connected.
[6]
Motor check,
alarm
Issues an alarm if the motor is not
connected.
1-81 Min Speed for Function at Stop [RPM]
Range:
Function:
Size related
*
[0 - 600 RPM] Set the speed at which to activate
1-82 Min Speed for Function at Stop [Hz]
Range:
Function:
Size related
*
[0.0 - 20.0 Hz]
3.3.8 Trip at Motor Speed Low Limit
In
4-11 Motor Speed Low Limit [RPM]
and
it is possible to set a minimum speed for the
motor in order to ensure proper oil distribution.
In some cases e.g. if operating in current limit because of a
defect in the compressor, the output motor speed can be
suppressed below Motor Speed Low Limit. To prevent
damage to the compressor it is possible to set trip limit. If the
motor speed drops below this limit, the frequency converter
will trip and issue an alarm (A49).
Reset will take place according to the selected function in
.
If the trip must take place at a rather exact speed (RPM), it is
recommended to set
for RPM and use
slip compensation, which can be set in
.
NOTE
To achieve the highest accuracy with the slip compensation,
an Automatic Motor Adaptation (AMA) should be performed.
To be enabled in
1-29 Automatic Motor Adaptation (AMA)
.
NOTE
Trip will not be active when using a normal stop- or coast
command.
1-86 Trip Speed Low [RPM]
Range:
Function:
Size related
*
[0 - par. 4-13 RPM]
NOTE
This parameter is only available if
is set
to [RPM].
1-87 Trip Speed Low [Hz]
Range:
Function:
Size related
*
[0.0 - par. 4-14 Hz]
NOTE
This parameter is only available if
is set
to [Hz].
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
43
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