Question

A timer contact should be selected for the following operation: when the timer is energized, the normally open contact is closed. When the timer is de-energized, the normally open contact is opened.

A. Retentive on-delay timer timing contact.
B. Non-retentive on-delay timer timing contact.
C. Non-retentive off-delay timer timing contact.
D. All of the above.

Answer 1

The correct type of timer contact for the described operation is a non-retentive on-delay timer timing contact, which closes when energized and opens when de-energized.

Step-by-step explanation:

The question is asking which type of timer contact should be selected for an operation where the normally open contact closes when the timer is energized, and opens when the timer is de-energized. The correct option here is B. Non-retentive on-delay timer timing contact. This type of timing contact does not retain the output state after the input is removed; instead, it returns to the initial state. Thus, when energized, it will close the normally open contact, and when power is removed, it will return to the open state.