How to wire the time-delay starting switch of the switchgear

The time-delay starting switch of the switchgear is usually realized through a **time relay**, which is used to control the time-delay 

starting of equipment (such as a motor). The following are common wiring methods, taking the **power-on time-delay type 

time relay (such as JSZ3V, HH54P)** as an example:

 I. Preparation Before Wiring

1. **Component List**:

   - Time relay (KT)

   - Circuit breaker (QF), contactor (KM), start button (SB1), stop button (SB2)

   - Thermal relay (FR, for motor protection)

2. **Terminal Instructions of the Time Relay** (taking an 8-pin one as an example):

 II. Control Logic and Circuit Diagram

**Function**: After pressing the start button, the motor will start after a time delay of **T seconds**.

**Circuit Diagram**:

Control power supply (AC 220V)  

L ── QF ── SB2 ── SB1 ── KT coil (A1) ── N  

          └─ KT instantaneous NO (7-8) ── KM coil ── FR ── N  

KT time-delay NO (3-4) ── KM auxiliary normally open ── Connected in parallel at both ends of SB1 (self-locking)

III. Specific Wiring Steps

 1. Wiring of the Main Circuit

1. Connect the power inlet wire (L1/L2/L3) to the input terminal of the circuit breaker **QF**.

2. Connect the output terminal of QF to the input terminal of the main contact of the contactor **KM**.

3. Connect the output terminal of the main contact of KM to the motor **M**, and connect the main contact of the thermal

 relay **FR** in series.

2. Wiring of the Control Circuit

1. **Time Relay Coil Circuit**:

   - Control power supply L → Normally closed contact of the stop button **SB2** → Normally open contact of the start button 

**SB1** → Time relay **KT coil (A1)** → Control power supply N.

   - **Note**: The voltage of the KT coil needs to be consistent with the control power supply (such as AC 220V or DC 24V).

2. **Time-delay Self-locking Circuit**:

   - One end of the time-delay normally open contact (3-4) of the time relay is connected to the control power supply L, and the

 other end is connected to one end of the contactor **KM coil**.

   - The other end of the KM coil is connected to the normally closed contact of the thermal relay **FR**, and then connected to 

the control power supply N.

   - **Self-locking**: Connect the auxiliary normally open contact of KM in parallel at both ends of SB1.

3. Instantaneous Contact (Optional)

If it is necessary to trigger other equipment during startup, the instantaneous normally open contact (7-8) of the time relay can be

 used, and it is wired independently from the time-delay contact.

IV. Wiring Schematic Diagram

* (Note: It actually needs to be adjusted according to the specific component terminal diagram)

V. Precautions

1. **Distinguish the Types of Time Delay**:

   - Power-on time-delay type (the KT coil acts with a time delay after being powered on);

   - Power-off time-delay type (the KT coil resets with a time delay after being powered off).

   Select the type of relay according to the requirements.

2. **Contact Capacity**:

   The contact current of the time relay is usually small (such as 5A), and it cannot directly control a large-current load. It needs

 to be transferred through a contactor.

3. **Time Setting**:

   Adjust the knob or digital panel of the time relay to set the time delay (such as 0-60 seconds).

4. **Safe Operation**:

   Disconnect the power supply before wiring, and use a multimeter to confirm the continuity of the circuit to avoid short circuits.

VI. Common Fault Troubleshooting

Through the above steps, the time-delay starting function of the switchgear can be realized, which is suitable for scenarios such as

 soft starting of motors and sequential control of equipment.