Abstract： IEC 60947-4-2:2011 pdf free download.Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - AC semiconductor motor controllers and starters. 3.3.2 a.c. semiconductor motor controller semiconductor switching devic...

IEC 60947-4-2:2011 pdf free download.Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - AC

semiconductor motor controllers and starters.

3.3.2

a.c. semiconductor motor controller

semiconductor switching device that provides the starting function for an a.c. motor and an OFF-state

NOTE 1 Because dangerous levels of leakage currents can exist in a semiconductor motor controller in the OFF- state, the load

terminals should be considered as live parts at all times.

NOTE 2 In a circuit where the current passes through zero (alternately or otherwise), the effect of snot making the current

following such a zero value is equivalenl to breaking the current.

3.3.3

semiconductor motor controller (form 1)

a.c. semiconductor motor controller, in which the starting function may comprise any starting method specified by the manufacturer, and that provides control functions which may include any combination of manoeuvring, controlled acceleration, running or

controlled deceleration of an a.c. motor. A FULL-ON state may also be provided

NOTE See Figure 1 and Table 1.

3.3.4

semiconductor soft-start motor controller (form 2)

special form of a.c. semiconductor motor controller, in which the starting function is limited to a voltage and/or current ramp

which may include controlled acceleration, and where the additional control function is limited to providing FULL-ON.

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