 | Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut für Berufliche Entwicklung, 201 p.) |
 |  | 2. Bell Circuits |
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(introduction...)
The reference letters and numbers in the illustrations of bell circuits have the following meanings:
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a |
switch |
E |
voltage source |
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b |
control switch |
f |
transducer |
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c |
contactor |
g |
measuring instrument |
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d |
auxiliary contactor, relay |
h |
visual and audio alarm |
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e |
protective device |
Tr |
transformer |
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