Capacitor Relay Timing in Industrial Control

The trend toward electrical means of providing timing for motor control is evidenced in the use of capacitor-timed relays and contactors. Though employed for some time in welding applications, the advent of capacitor timing in the motor control field is fairly recent. The general analytical considerations are presented, followed by a discussion of the component parts of the timer. Some attention is paid to limitations, particularly in regard to the effect of line voltage fluctuations.