What is the NEMA or industry standard symbol used for an NOTC set of timing relay contacts?

The NEMA standard symbol for a set of timing relay contacts categorized as NOTC (Normally Open Timing Contacts) is represented by the letter D. This designation is used to signify the operational characteristics of the contacts within a timing relay circuit.

In the context of timing relays, these contacts operate in a way that, when the relay is energized, the contacts remain open for a specific duration before closing once the timed period elapses. The use of the letter D helps differentiate these timing contacts from others that may operate under different conditions or configurations, thus facilitating easier identification and understanding of their function by those working with electrical control systems.

This standardization by NEMA allows electricians and engineers to have a consistent language when discussing relay and contact types, which promotes clarity and efficiency in wiring diagrams and electrical schematics. Understanding the designation of timing relay contacts is crucial for correct installation and troubleshooting processes in electrical systems.