Technical information

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 frequency converter will continue to run, but
activate a Broken Belt Warning [W95]. A
frequency converter digital output or a serial
communication bus can communicate a warning
to other equipment.
[2] Trip The frequency converter will stop running and
activate a Broken Belt alarm [A 95]. A frequency
converter digital output or a serial communi-
cation 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 frequency converter to continuously cycle
between running and stopping when a broken belt
condition is detected.
NOTE
If the frequency converter is equipped with a constant
speed bypass with an automatic bypass function that starts
the bypass if the frequency converter 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: Function:
10 %* [0 - 100 %] Sets the broken belt torque as a percentage
of the rated motor torque.
22-62 Broken Belt Delay
Range: Function:
10 s [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.
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: Function:
[0] * Disabled
Timer set in 22-76 Interval between Starts is
disabled.
[1] Enabled
Timer set in 22-76 Interval between Starts is
enabled.
22-76 Interval between Starts
Range: Function:
Size related* [ par. 22-77
- 3600 s]
Sets the time desired as minimum
time between two starts. Any
normal start command (Start/Jog/
Freeze) will be disregarded until the
timer has expired.
22-77 Minimum Run Time
Range: Function:
0 s* [ 0 - par.
22-76 s]
Sets the time desired as minimum run time
after a normal start command (Start/Jog/
Freeze). Any normal stop command will be
disregarded until the set time has expired. The
timer will start counting following a normal
start command (Start/Jog/Freeze).
The timer will be overridden by a Coast
(Inverse) or an External Interlock command.
NOTE
Does not work in cascade mode.
3.20.7 22-8* Flow Compensation
It is sometimes the case that is not possible for a pressure
transducer to be placed at a remote point in the system
and it can only be located close to the fan/pump outlet.
Flow compensation operates by adjusting the set-point
according to the output frequency, which is almost propor-
tional to flow, thus compensating for higher losses at
higher flow rates.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG11CD02 - VLT
®
is a registered Danfoss trademark 155
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