Clock Timers
Another timer frequently used is the clock timer (Figure 7 – 9). Clock timers use a small AC synchronous motor similar to the motor found in a wall clock to pro- vide the time measurement for the timer. The length of time of one clock timer may vary greatly from the length
Min. Time Delay: 0.05 second Max. Time Delay: 3 minutes Minimum Reset Time: 0.75 second Accuracy: 610 percent of setting Contact Ratings:
Types of Contact: One normally open and one normally closed. Cadmium silver alloy contacts.
of time of another. For example, one timer may have a full range of 0 to 5 seconds and another timer may have a full range of 0 to 5 hours. The same type of timer motor could be used with both timers. The gear ratio connected to the motor would determine the full range of time for the timer. Some advantages of clock timers are:
A. They have extremely high repeat accuracy.
B. Readjustment of the time setting is simple and can be done quickly. Clock timers are generally used when the machine operator must make adjustments to the time length.