Introduction to Industrial Automation

Figure 3.21  (a) Power circuit, (b) windings connection, and (c) automation circuit of a motor 

with Y/Δ start-up.

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  Introduction to Industrial Automation

3.5   Automation Circuits with Sensors

The automation circuits that have been examined until now contained only relays (power or aux-

iliary ones), time relays, buttons or switches, and contacts as logical components. In cases where 

an automatic command has been utilized, this took place in an abstract approach, with a refer-

ence to a hypothetical sensor. These circuits did not contain sensors, since we were not address-

ing physical operations needing the detection of specific physical quantities. Subsequently, more 

automation circuits containing basic types of sensors will be examined. Finally, it should be noted 

that the logic for the utilization and integration of additional different types of sensors than those 

addressed here would be similar.