Priniciples of Electromechanical Relay Operation


3.19 Timing Characteristics

Normally operate and release times are not of concern in the application of ac actuated relays due to the timing variation that occurs as a result of the varying amplitude of the applied source voltage and the point in the waveform at which the coil voltage is applied or released. If it is necessary to specify operate/release values for an ac operated relay for comparison purposes, a dc operated voltage can be specified at a level approximately 25% higher than the measured dc just operate value and operate/release timing values measured. This method will provide meaningful, repeatable results without the ambiguity resulting from waveform amplitude in ac applied coil voltages at turn on or turn off.