3 Phase Motor Connection Diagram with SSR and Selector Switch

Here, in this article, we are going to see the connection diagram and wiring between a 3-phase motor, SSR, and Selector switch to turn On and turn Off the motor by operating the selector switch. Basically, here we have used SSR instead of a magnetic contactor or electromechanical relay to control the motor. There are so many advantages of SSR which is why we should use the SSR for motor control. Of course, for more controlling options and complex control circuits, a Contactor should be used instead of an SSR. But when we need only On/Off operation is it good to use an SSR.

Solid State Relays (SSRs) are used with motors for several advantages compared to traditional magnetic contactors and electromechanical relays.

For example, SSRs can switch on and off very quickly, which is important in motor control applications where precise switching timing is required. This can help to improve the overall efficiency and performance of the motor controlling system.

The other advantage is unlike magnetic contactors or electromechanical relays, SSRs have no mechanical moving parts. This means they are more reliable and have a longer lifespan because there is no wear and tear due to mechanical switching.

Connection Diagram

Here, you can see the connection between a 3-phase motor, an SSR, and a Selector switch.

Components Used

• A 4-Pole MCB(as a main breaker)
• A Three Phase SSR with 230V AC operating supply
• A normal On/Off Selector Switch

Wiring Procedure

1. The 4-Pole MCB is used as a main incoming switch or main breaker. So the main input power supply is connected to the input of the MCB.
2. All three phases from the output of the MCB are connected to the three-phase input terminals(A1, B1, C1) of the SSR.
3. The three-phase input terminals of the motor are connected to the output terminals(A2, B2, C2) of the SSR.
4. The neutral terminal from the output of the MCB is directly connected to the neutral terminal of the SSR.
5. Anyone phase terminal(here B phase is used) is connected to the Phase terminal of the SSR in series with the selector switch.

Operating Procedure

1. First of all, the MCB should be turned On.
2. Now when we want to run the motor, we should put the selector switch in the On position.
3. When we keep the switch in the Off position the motor will be turned Off.

Working Principle

As you see, the SSRs have a low-voltage control input (here it uses 230V AC) that is used to activate or deactivate the solid-state relay. So, when keeping the switch in the On position, the 230V AC control input voltage is applied, which triggers the semiconductor switch within the SSR. So, the SSR got turned On, and the current started flowing from the input side to the output side and the motor started running.

When we turn the switch in the Off position, the control input voltage from the SSR is removed or goes below a certain threshold which causes it to turn off the semiconductor switch in the SSR and finally, the power supply is cut off from the load(here motor).

Read Also: 

• VFD Wiring Diagram with Motor, Switches, and External Devices
• Dynamic Braking Resistor (DBR) Connection Diagram with VFD
• Submersible Pump Starter and Water Level Controller Wiring Diagram
• 3-Phase Motor and VFD Wiring Diagram with Single-Phase Supply
• Double Motor Control with Selector Switch Connection

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