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The picture below is a power circuit for a direct-on-line starter, given in any ABB catalog for contactor. Q1 is a manual motor started with overcurrent protection. My question is

  • What is the meaning of the "_F"-like symbol. Does it represent an edge trigger?
  • What is the square after the "_F"-like symbol. Does it represent the coil of the contactor?
  • What is the "/>" symbol? Does it represent overcurrent protection?

I presume that the pulse-like symbols are for thermal overload.

enter image description here

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  • \$\begingroup\$ the symbol at Q1 looks like a rising edge symbol, do you are probably correct about the edge triggering ... it just happens to be intersecting the horizontal dashed line \$\endgroup\$
    – jsotola
    Sep 26 '20 at 4:19
  • \$\begingroup\$ You are right. The dotted line touch the edge trigger. They normally use rectangle to represent coil of a contactor, like KM1. However, I do not know why it uses square for Q1 \$\endgroup\$
    – yoonghm
    Sep 26 '20 at 4:47
  • \$\begingroup\$ The square has a "+" symbol inside. So it's an addition of the two protection mechanisms . \$\endgroup\$ Sep 26 '20 at 14:06
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After searching around (https://search.abb.com/library/Download.aspx?DocumentID=2CDC131025D0201&LanguageCode=en&DocumentPartId=&Action=Launch), here is my answer to my own question:

  • The "F" symbol represent an edge-triggering signal
  • The pulse symbol represents thermal tripping element for overload protection
  • The "I>" symbol represents electromagnetic tripping element for short-circuit protection
  • The square represents facility to activate tripping of the two elements above
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  • \$\begingroup\$ ... and that's not a contractor (i.e. a high power relay) but a circuit breaker (basically a hand operated switch) \$\endgroup\$
    – carloc
    Sep 26 '20 at 6:52
  • \$\begingroup\$ @carloc What about A1 A2? It looks electrically operated to me(?) More details might help me understand. \$\endgroup\$ Sep 27 '20 at 16:22
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    \$\begingroup\$ Q1 is the circuit breaker, KM1 is the contactor, they are two separated devices wired one after the other \$\endgroup\$
    – carloc
    Sep 27 '20 at 16:48
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Symbols are according to DIN EN 60617 / IEC 60617-2:1996

German Wikipedia shows some of the symbols

https://de.wikipedia.org/wiki/Liste_der_Schaltzeichen_(Elektrik/Elektronik)#Schutzschalter

e.g.

enter image description here

is a 3 pole motor protecting switch

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Q1 is a 'motor protection circuit breaker' which offers short-circuit, overload and phase failure protection in a single device.

enter image description here

The '_F' symbol denotes a knob- or lever-operated 'on/off' device.

The 'pulse like' symbol denotes thermal-operated overload/phase failure protection.

The 'I >' symbol denotes electromagnetic short-circuit protection.

The 'square' denotes overload and short circuit protection linkage to the knob/lever. The knob/lever switches the breaker on or off. It is also tripped 'off' when overload/short circuit/phase failure occurs.

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