ABB OTM C 21D - Page 6

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AUTOMATIC TRANSFER SWITCH, OTM_C_21D
The transfer sequence of OTM_C21D can be sum-
marized in following steps:
• An anomaly occurs on the Line 1 (LN1)
• Transfer delay Ts, in case of black-out, phase-
loss, overvoltage and undervoltage conditions
• Change-over switch (Switch I) to the position 0
• Change-over switch (Switch II) to the position II
And the return sequence can be summarized in
the following steps:
• The Line 1 will start the normal functioning
• Change-over switch stays in position II
• An anomaly occurs on the Line 2 (LN2)
• Return delay TBs
• Change-over switch (Switch II) to the
position 0
• Change-over switch (Switch I) to the position I
Figure 3. Automatic Switching Sequences in OTM_C_21D, No line priority
Generator can not be used in no line priority. Keep Dip switch “GEN SEL” setting “0”
in this mode.
2.2.2 No line priority