Timing relay driven by sync. motor - has series diode switched in to disable motor when set time expires

摘要

The timing relay has a sync. motor rotating a timing disc against the action of a return spring. The disc operates the relay's contacts when the preset time has elapsed and disables the motor. A diode(D) is connected in series with the motor (M) and is shorted out by a switch whilst the preset time is running. This switch is opened by a cam on the disc when the time expires. The diode may be in series with a resistor and the resulting combination shorted by the switch. The motor may be shunted by a capacitor.