Open gate – Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) User Manual

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Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013

Chapter 1

Product Overview

Figure 13

illustrates the required PTC sensor characteristics, per IEC-34-11-2.

Figure 13 - PTC Sensor Characteristics per IEC-34-11-2

PTC Trip

The MV SMC Flex will trip with a PTC indication if:

No other fault currently exists

PTC protection is enabled

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

Open Gate

An open-gate fault indicates that improper SCR firing, typically caused by an
open SCR gate or driver system, 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 (or as programmed in Parameter 82).

An open gate is detected when the module sends a gate signal to the SCRs but
does not detect that they turned on. SCR turn-on is detected when the voltage
across the leg (L-T) collapses. The Open Gate detection is active during starting
or stopping only.

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