Table 4-1 Pickup Level Settings For Variable Undercurrent Protection Example - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

Advanced Motor Protection Parameters
4.1 Standard Protections Block Diagram
The bottom two rows of the second figure shown show more complex behaviors involving
shorter time variations of the pickup signal.
Boolean Logic equations for the counters are
Pickup Counter
● Count = /Pickup timed out * enabled * pickup
● Reset = Reset (ext) + Dropout timed out
Dropout Counter
● Count = /(/Pickup * /Pickup timer) * (/Pickup timed out
control * Pickup timed out)
● Reset = /(Dropout timed out + /Dropout) * (Pickup timed out * Latch
control) + Reset (ext)
where:
/ indicates a logical inversion (not)
+ indicates a logical OR
* indicates a logical AND
Fixed Pickup Protections
Fixed pickup protection functions allow a single pickup level to be programmed that remains a
constant over the entire operating speed range of the drive.
Example: For fixed pickup overspeed protection, when the speed of the machine exceeds the
programmed pickup level then the logic of the standard block diagram starts the pickup timer.
If the pickup condition persists for longer than the programmed time then a trip or alarm will
occur.
The pickup level is independent of the speed setting (speed demand) of the drive.
Demand Dependency for Variable Pickup Protections
Variable pickup protection functions allow a pickup level to be programmed as a function of the
commanded speed of the drive (speed demand). The pickup levels are entered as a set of 20
points starting from 0% demand to 190% demand setting. Linear interpolation is used between
the points.
Example: If a 10% overspeed pickup is set at 0% demand and a 20% overspeed pickup is set
at 10% demand, the effective pickup level at 5% demand will be 15%. The pickup level will
remain constant at the 190% demand setting for demand settings in excess of 190%. If the
190% demand setting pickup level is set to 210%, the pickup level at 200% demand will also be
210%. See Figure
To further illustrate, assume that the variable pickup undercurrent function is being used; and
the pickup levels are set to the values shown in column 2 of Table
Level Settings for Variable Undercurrent Protection Example".
Table 4-1
20
Variable Pickup Undercurrent .
Pickup Level Settings for Variable Undercurrent Protection Example
Speed Demand (%)
0
10
20
"Pickup Level Settings for
Undercurrent Pickup Level (%)
10
10
10
Advanced Motor Protection for Variable Speed Operation
Manual, AA, A5E46373908A
+ /Latch