Unformatted text preview: 1110 16. Solutions 16.1
Solutions to exercises
from Chapter 2 Exercise 2.1 Protective circuits for electro-mechanical limit switches
Differentiation must be made between ohmic, inductive and capacitive loads.
Depending on the type of load, a suitable protective circuit is to be designed in order
to achieve a longer service life for the switching contacts. Ohmic load If the load is purely ohmic, no additional protective measures need to be taken to
observe the limit values of the respective data sheet. Capacitive load A great amount of current flows briefly if a capacitive load is switched on. If this
current exceeds the value specified in the data sheets, external measures must be
taken to restrict it. A protective resistor is connected in series with the switch. The
design of the protective circuit is in accordance with the formula
R = V / Imax
with switching voltage V and maximum switching current Imax. The resistance is to be
selected so that it can accept the required electrical power. Inductive l...
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- Spring '12