Wiring Methods of Time Relays

A time relay is an automatic switching device that realizes delay control by using electromagnetic principles or mechanical 

principles. There are many types of it, and the wiring methods vary depending on the type. The following are the wiring

 methods of some common time relays:

 I. On-delay Time Relay

1. **Coil Wiring**

   - Generally, the coil of the time relay has two pins, which are respectively connected to the phase wire (L) and the neutral 

wire (N) of the power supply. For example, connect one end of the coil to the L terminal of the power supply and the other 

end to the N terminal. In this way, when the power supply is turned on, the coil of the time relay will be energized.

2. **Normally Open Contact Wiring**

   - Normally open contacts are usually used to control devices that need to start with a delay. For instance, connect one end

 of the normally open contact to the L terminal of the power supply, and the other end to one end of the contactor coil. The

 other end of the contactor coil is connected to the N terminal. When the time relay is energized and starts timing, after

 reaching the set time, the normally open contact closes, the contactor coil is energized, and thus the device is controlled to start.

3. **Normally Closed Contact Wiring**

   - Normally closed contacts are often used to control devices that need to stop with a delay. Suppose one end of the normally 

closed contact is connected to the L terminal of the power supply, and the other end is connected to one end of the contactor

 coil. The other end of the contactor coil is connected to the N terminal. When the time relay is energized and starts timing, 

within the set time, the normally closed contact is closed, and the device runs normally; after reaching the set time, the normally

 closed contact opens, the contactor coil loses power, and the device stops running.

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 II. Off-delay Time Relay

1. **Coil Wiring**

   - Similar to the on-delay type, the coil is connected to the phase wire (L) and the neutral wire (N) of the power supply.

2. **Normally Open Contact Wiring**

   - In the off-delay time relay, the normally open contacts are used to control devices that need to stop after a certain delay

 when the power supply is cut off. For example, connect one end of the normally open contact to the L terminal of the power

 supply, and the other end to one end of the contactor coil. The other end of the contactor coil is connected to the N terminal. 

When the time relay is energized, the normally open contact closes, and the device runs; when the power supply is cut off, the

time relay starts timing. Within the set time, the normally open contact remains closed, and the device continues to run; after 

reaching the set time, the normally open contact opens, and the device stops running.

3. **Normally Closed Contact Wiring**

   - Normally closed contacts are used to control devices that need to start after a certain delay when the power supply is cut off.

 Connect one end of the normally closed contact to the L terminal of the power supply, and the other end to one end of the contactor

 coil. The other end of the contactor coil is connected to the N terminal. When the time relay is energized, the normally closed contact 

opens; when the power supply is cut off, the time relay starts timing. After reaching the set time, the normally closed contact closes,

 the contactor coil is energized, and the device starts.

 III. Air Damping Type Time Relay

1. **Coil Wiring**

   - Also connect to the phase wire (L) and the neutral wire (N) of the power supply.

2. **Delay Contact Wiring**

   - The air damping type time relay has normally open contacts that close with a delay and normally closed contacts that open 

with a delay. Its wiring method is similar to the wiring of the corresponding contacts of the above on-delay and off-delay time relays.

 According to the actual control requirements, connect the delay contacts to the circuit of the controlled device. For example, if you

 want to achieve the delayed start of the device, you can connect the normally open contact that closes with a delay in series with 

the contactor coil; if you want to achieve the delayed stop of the device, you can connect the normally closed contact that opens 

with a delay in series with the contactor coil.

 IV. Electronic Time Relay

1. **Power Supply Wiring**

   - The power supply wiring of an electronic time relay usually has a distinction between direct current and alternating current. For

 a direct current power supply, there are generally positive (+) and negative (-) poles. Connect the positive pole to the positive terminal 

of the power supply and the negative pole to the negative terminal of the power supply; for an alternating current power supply, 

directly connect the two power supply wires to the power input terminals of the time relay respectively.

2. **Control Contact Wiring**

   - The control contacts of an electronic time relay also have normally open and normally closed types. Its wiring method is basically 

the same as that of the control contacts of other types of time relays. According to specific control requirements, connect the normally

 open or normally closed contacts to the corresponding control circuit to achieve the delay control of the device.

 V. Digital Time Relay

1. **Power Supply Wiring**

   - The power supply wiring method of a digital time relay is similar to that of an electronic time relay. According to its operating 

voltage requirements, correctly connect the phase wire (L) and the neutral wire (N) of the power supply or the positive and negative

 poles of the direct current power supply.

2. **Control Contact Wiring**

   - The control contacts of a digital time relay also have normally open and normally closed types, and its wiring method is also 

similar to that of other types of time relays. By connecting the control contacts to the circuit of the controlled device, precise delay 

control of the device can be achieved. In addition, digital time relays usually also have some other functional pins, such as reset pins,

 pause pins, etc., and corresponding wiring and settings can be made according to actual needs.

 VI. Wiring Precautions

1. **Power Supply Voltage Matching**

   - Before wiring, be sure to confirm that the rated operating voltage of the time relay is consistent with the voltage of the 

connected power supply. Otherwise, it may cause damage to the time relay or prevent it from working properly.

2. **Contact Capacity**

   - Select a time relay with an appropriate contact capacity according to the current of the controlled device. If the contact

 capacity is too small, problems such as contact ablation and adhesion may occur during use, affecting the normal operation

 of the device.

3. **Firm Wiring**

   - Ensure that all connection points are firm and reliable when wiring, and avoid situations such as looseness and poor contact

 to prevent problems such as poor contact and arcing, and even cause safety accidents.

4. **Follow the Circuit Diagram**

   - Wire strictly according to the instruction manual or circuit diagram of the time relay to ensure that the wiring is correct. If you

 are not sure about the wiring method, you should consult relevant materials or professionals in time.

5. **Safe Operation**

   - During the wiring process, make sure that the power supply has been cut off to avoid electric shock accidents. At the same time,

 before the power-on test, carefully check whether the wiring is correct, and only turn on the power after confirming that it is correct.

In short, the wiring method of the time relay needs to be correctly connected according to its type, function, and actual control 

requirements. Pay attention to safety during the wiring process and follow relevant specifications and requirements to ensure 

that the time relay can work properly and achieve precise delay control of the device.