Littelfuse MPS - Autotransformer Closed-Transition Starter; Wye-Delta Closed-Transition Starter; Two-Winding-Starter Connection

Page 6-13
MPS Motor Protection System Rev. 6-F-022117
Starter Functions
FIGURE 6.20 Two-Winding-Starter Connection.
6.15 AUTOTRANSFORMER CLOSED-TRANSITION
STARTER
Sequence: Fig. 6.7
Connection: Fig. 6.22
Current Transfer: Available
START1 or START2 initiates the sequence. Starter
RLYC activates to close the neutral contactor (K3) on the
autotransformer. Starter RLYB activates to close the main
autotransformer contactor (K2) after the Stage1 Delay.
Starter RLYC de-activates to open the autotransformer
neutral contactor after the Stage2 Delay, and Starter
RLYA activates to close the main motor contactor (K1)
after the Stage3 Delay. Stage-1 and Stage-3 delays are
contactor-transfer times and should be set in the range of
0.1 to 0.5 seconds.
6.16 WYE-DELTA CLOSED-TRANSITION STARTER
Sequence: Fig. 6.8
Connection: Fig. 6.23
Current Transfer: Available
START1 or START2 initiates the start sequence.
Starter RLYC activates to close the neutral contactor (K3).
Starter RLYB activates to close the wye contactor (K2)
after the Stage1 Delay. Starter RLYD activates to close
the resistor contactor (K4) after the Stage2 Delay. This is
followed by de-activation of Starter RLYC, activation of
Starter RLYA to close the main motor contactor (K1), and
de-activation of Starter RLYD, all displaced by the Stage1
Delay.
Locate CT’s on the line side of the starter. Set FLA
Rating to the delta full-load current and FLA Rating 2 to
the wye full-load current. Stage-1 delay is a contactor-
transfer time and should be set in the range of 0.1 to 0.5
seconds.