Danfoss VLT FC 100 Series Programming Manual page 166

Parameter Description
NOTE!
If the adjustable frequency drive is equipped with a
constant speed bypass with an automatic bypass function
that starts the bypass if the adjustable frequency drive
experiences a persistent alarm condition, be sure to disable
the bypass's automatic bypass function, if [2] Alarm or [3]
Man. Reset Alarm is selected as the End of Curve Function.
22-51 End of Curve Delay
Range: Function:
10 s [0 - 600 When an end of curve condition is detected, a
*
s] timer is activated. When the time set in this
parameter expires and the End of Curve
condition has been steady in the entire period,
the function set in 22-50 End of Curve Function
will be activated. If the condition disappears
before the timer expires, the timer will be reset.
3.20.5 22-6* Broken Belt Detection
Broken belt detection can be used in both closed-loop and
open-loop systems for pumps, fans and compressors. If the
estimated motor torque is below the broken belt torque
value (22-61 Broken Belt Torque) and the adjustable
frequency drive output frequency is above or equal to 15
Hz, the broken belt function (22-60 Broken Belt Function) is
performed.
22-60 Broken Belt Function
Selects the action to be performed if the Broken Belt condition is
detected
Option: Function:
[0] OFF
*
[1] Warning The adjustable frequency drive will continue to
run, but will activate a Broken Belt Warning
[W95]. An adjustable frequency drive digital
output or a serial communication bus can
communicate a warning to other equipment.
[2] Trip The adjustable frequency drive will stop running
and activate a Broken Belt alarm [A 95]. An
adjustable frequency drive digital output or a
serial communication bus can communicate an
alarm to other equipment.
NOTE!
Do not set 14-20 Reset Mode to [13] Infinite auto reset
when 22-60 Broken Belt Function is set to [2] Trip. Doing so
will cause the adjustable frequency drive to continuously
cycle between running and stopping when a broken belt
condition is detected.
®
VLT HVAC Drive Programming Guide
NOTE!
If the adjustable frequency drive is equipped with a
constant speed bypass with an automatic bypass function
that starts the bypass if the adjustable frequency drive
experiences a persistent alarm condition, be sure to disable
the bypass's automatic bypass function, if [2] Trip is
selected as the Broken Belt Function.
22-61 Broken Belt Torque
Range:
10 %
22-62 Broken Belt Delay
Range:
10 s
3.20.6 22-7* Short Cycle Protection
When controlling refrigeration compressors, often there
will be a need for limiting the numbers of starts. One way
to do this is to ensure a minimum run time (time between
a start and a stop) and a minimum interval between starts.
This means that any normal stop command can be
overridden by the Minimum Run Time function
(22-77 Minimum Run Time) and any normal start command
(Start/Jog/Freeze) can be overridden by the Interval
Between Starts function (22-76 Interval between Starts).
None of the two functions are active if Hand On or Off
modes have been activated via the LCP. If selecting Hand
On or Off, the two timers will be reset to 0, and not start
counting until Auto is pressed and an active start
command applied.
NOTE!
A Coast command or missing Run Permissive signal will
override both Minimum Run Time and Interval Between
Starts functions.
22-75 Short Cycle Protection
Option:
[0]
[1]
MG11CD22 - VLT ® is a registered Danfoss trademark
Function:
[0 - 100 %] Sets the broken belt torque as a percentage
*
of the rated motor torque.
Function:
[0 - 600 s] Sets the time for which the broken belt
conditions must be active before carrying out
the action selected in 22-60 Broken Belt
Function.
Function:
Disabled Timer set in 22-76 Interval between Starts is
*
disabled.
Enabled Timer set in 22-76 Interval between Starts is
enabled.
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