That looks correct. SCR cathode to both commons and both commons tied together. SCR anode to your load (motor) low side (neg) and motor high side (pos) to your motor supply positive. Pushing the button will latch the motor On and opening the switch will stop the motor.

Ron

Great

If we need to add electrode capacitor
The drawing and schematic will be like this right?

 

The drawing and schematic will be like this right?

No. You are still confusing the gate and cathode in the drawing (not the schematic) unless, as Les said, you have a non-standard SCR. What SCR type are you using? Tell us the type, or else post a link to its specification.
If you post drawings of your circuit, make sure they have labels clearly identifying the anode, cathode and gate of your SCR. Without those labels you are likely to remain confused.
The electrolytic capacitor you added in your latest drawing is correctly placed in the circuit.

 

No. You are still confusing the gate and cathode in the drawing (not the schematic) unless, as Les said, you have a non-standard SCR. What SCR type are you using? Tell us the type, or else post a link to its specification.
If you post drawings of your circuit, make sure they have labels clearly identifying the anode, cathode and gate of your SCR. Without those labels you are likely to remain confused.
The elctrolytic capacitor you added in your latest drawing is correctly placed in the circuit.

First pin (above) Cathode
Middle pin is anode
Third pin is gate


It is btw69-1200 thyristor

 

If you SCR has the non standard pinout that you give at the end of post #63 then it is wired correctly. What is the part number of your SCR ?

Les.

 

If you SCR has the non standard pinout that you give at the end of post #63 then it is wired correctly. What is the part number of your SCR ?

Les.

Btw69-1200

 

This datasheet that I found for the BTW69 shows that it has the standard pinout. (Which means that your drawing is wrong.) Can you post the datasheet that gave the pinout that you posted in post #63 ?

Les

 

I think i have confused about the position of thyristor in drawing and its pins

So it show be like this

 

Your drawing in post #67 is now correct.

Les.

 

Agreed. The mounting tab of the SCR is important in identifying the orientation of the package.
Note that the tab is internally connected to the anode pin for that specific SCR.

 

Your drawing in post #67 is now correct.

Les.

Hallelujah!

I think much of the problem was confusion about the pins on the device when shown in a different orientation.

 

If iam adding capacitor
First one is the right or second one or both?

Here is the schematic

 

First one is the right or second one or both?

They are electrically equivalent, providing the capacitor leg is able to carry the full motor current.