Time relay symbol

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Interpretation: A time relay is an automatic switching device that achieves delay control through electromagnetic or mechanical principles. It is typically categorized into two types: power-on delay and power-off delay. Although there are only two main types, the graphical symbols of the time relay can be confusing when drawing or interpreting electrical schematics. Especially, the time-delay contacts of the time relay can be difficult to identify in practical use. Let’s help you understand this better.

1. Time Relay Symbol - Introduction

A time relay is an automatic switching device that uses electromagnetic or mechanical principles to achieve delayed control. It is commonly used in circuits with low voltage or current to control high-voltage or high-current circuits. When an input signal is applied (or removed), the output circuit undergoes a specific, precise time delay before producing a jump change or contact action. Time relays come in various types, such as air-damping, electric, and electronic models.

2. Time Relay Symbol - Text Symbol

Text symbol:

3. Time Relay Symbol - Graphic Symbol

Coil general symbol:

Graphic symbol for power-on delay:

Graphic symbol for power-down delay:

4. Time Relay Symbol - Electrical Symbols

Normally open symbol:

Normally closed symbol:

Time-closed normally open contact:

Time-opening normally closed contact:

Delayed recovery of closed normally closed contacts:

Time-opened normally open contact:

The time relay is mainly used to reflect the automatic control of time intervals. Its electrical symbol can also be expressed as shown below.

This concludes our introduction to the time relay symbol. Did you remember all of them? If not, just review it a few times. Here are some additional resources Xiaobian has prepared for you.