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3.2.1.3 Short-cycle Protection
The VLT® Compressor Drive CDS 803 includes a compressor short-cycling protection that prevents mechanical wear to the compres-
sor and reduces the risk of oil shortage caused by starting and stopping too often. The short-cycle protection consists of 2 timers:
The interval between starts ensures that a new start first becomes active when the start time has expired.
The minimum run time ensures that the compressor always runs for a defined minimum time before stopping the compressor.
Warning 96, Start Delay
is shown in the display if there is a start signal and the INTERVAL BETWEEN STARTS has not expired.
Warning 97, Stop Delay
is shown in the display if there is a stop signal and the MINIMUM RUNTIME has not expired.
e3
0b
j2
50
.1
0
Speed
Start signal
On
Off
Time
Time
Interval between
Starts expires
Warning 96
“Start Delay”
Illustration 4: Short Cycle Protection, Start Delay
e3
0b
j2
51
.1
0
Speed
Start signal
On
Off
Time
Time
Minimum run time expired
Warning 97
“Stop Delay”
Illustration 5: Short Cycle Protection, Stop Delay
3.2.1.4 Anti-reverse Protection
The anti-reverse protection function prevents the compressor scroll set from running in the wrong direction during stop.
AJ330233902305en-000201 / 130R0596
14 | Danfoss A/S © 2021.05
Product Overview
VLT® Compressor Drive CDS 803
Design Guide
