ELEKTRA main switches of the S-Series with undervoltage release comply with this requirement owing to an undervoltage release coil which, after power failure, makes the switch jump back to the ”off“ position by means of a mechanism. If the voltage has not been applied, the switch does not click. As an example, the functional diagram showing the incorporation of the emergency off push button (NC contact) and PTC temperature feeler (NC contact) into the control circuit. The coil trips the main switch if the control circuit is interrupted.
