Saf OPAL SS6 User Manual download pdf (Page 29)

OPAL SS6 Reduced Voltage Starters

Page 22

5.3 UP-TO-SPEED, SHEAR PIN, AND ENERGY SAVER

CA391 - MULTI OPTION CARD

5.3.1 UP-TO-SPEED AND SCR BY-PASS

A three pole contactor used in conjunction with the Up-To-Speed contact eliminates the

SCR losses by shorting them out after the motor has reached full speed. This feature is a true

Watt Saver modification and permits the use of the OPAL in a NEMA 4 or NEMA 12

enclosure. The by-pass contactor is switched on only after the motor has reached full speed

and as such sees only motor full load current. At stop, the by-pass contactor is opened while

the SCR's are triggered fully on, limiting the power contacts opening voltage. The SCR's are

then switched off without having any voltage surge.

When a by-pass contactor is used in conjunction with reversing, the FWD/REV contacts of

the CA388 must be connected in series for proper sequencing of the contactor(s).

When the motor reaches full speed, the Up-To-Speed relay is energized and the red UP-TO-

SPEED LED, LD3 is illuminated. A form C dry relay contact rated at 1A, 120VAC, is

provided on J1 terminals 1, 2 and 3 for by-pass sequencing. Large contactors require a

control relay to handle the high in rush current to the coil.

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Saf OPAL SS6 User Manual Page 29