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Rockwell Automation 150 SMC-Flex User Manual User Manual

Page 26

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Product Overview

The resistance across terminals 23 and 24 is either greater than
the relay’s response resistance or less than the short-circuit trip
resistance.

Excessive Starts/Hour

The SMC-Flex controller allows the user to program the allowed
number of starts per hour (up to 99). This helps eliminate motor stress
caused by repeated starting over a short time period.

Overtemperature

The SMC-Flex controller monitors the temperature of the SCRs and
Bypass by using internal thermistors. When the power poles’
maximum rated temperature is reached, the unit will shut down and
restart is inhibited.

An overtemperature condition can indicate inadequate ventilation,
high ambient temperature, overloading, or excessive cycling. After
the temperature is reduced to allowable levels, the fault can be
cleared.

Open Gate

An open gate fault indicates that improper SCR firing, typically
caused by an open SCR gate, has been detected on one of the power
poles. Before the controller shuts down, it will attempt to start the
motor a total of three times.

Line Faults

The SMC-Flex controller continually monitors line conditions for
abnormal factors. Pre-start protection includes:

Line Fault (with phase indication)

– Line voltage loss

– Missing load connection

– Shorted SCR

Running protection includes:

Line Fault (no phase indication)

– Line voltage loss

– Missing load connection

Phase Reversal

protection can be toggled either On or Off.

Phase Reversal protection is functional only at pre-start.