Danfoss VLT Programming Manual page 150

Parameter Description
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
The Broken Belt Detection can be used in both closed 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 frequency converter
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 drive will continue to run, but activate a Broken
Belt Warning [W95]. A drive digital output or a
serial communication bus can communicate a
warning to other equipment.
[2] Trip The drive will stop running and activate a Broken
Belt alarm [A 95]. A 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 drive to continuously cycle between running and
stopping when a broken belt condition is detected.
NOTE
If the drive is equipped with a constant speed bypass with an
automatic bypass function that starts the bypass if the 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: Function:
10 % [0 - 100 %] Sets the broken belt torque as a percentage
*
of the rated motor torque.
®
VLT HVAC Drive Programming Guide
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]
22-76 Interval between Starts
Range:
Size related
22-77 Minimum Run Time
Range:
0 s
NOTE
Does not work in cascade mode.
®
MG.11.CB.02 - VLT is a registered Danfoss trademark
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.
[par. 22-77 - 3600 s]
*
Function:
[0 - par. Sets the time desired as minimum run time after
*
22-76 s] 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.
3 3
Function:
149