Direct Start With SCR

This small project is carried out in the electrical automation but this time we will do it electronically where we will use the SCR for the interlocking of the system and no auxiliaries for contactors

GERBER PPCB:

https://mega.nz/file/3QAlgJBR#BbRr3aWnTh2vfu1vhUFcXlQN5ryS9LzFFtV_V9aL_JU

As with any project, we will first see the schematic diagram for its connections, that is, first we have to do the respective tests to then carry it out to a professional PCB. The schematic diagram was made in the easyEda program and it is with all its values ​​and electronic components that we will use. for this Proyect.

1° we will have to use a 5VDC power supply since the direct start system is designed for that voltage if we want to use a different voltage we will have to change the resistance that is in the ANODE of the SCR and make the respective calculations so that it can conduct only 20mA for the led diode for the already established voltage which is 5VDC we have two resistors in parallel of 100 ohms which in turn gives us 50 ohms since they are in parallel and this resistance limits the current in the led diode that it lets through only 0.015A or 15mA.

2nd we will have 2 buttons that will be 1 start and 1 stop, that is to say when we press start this positive signal will go to the SCR GATE and this will lead in one direction and will lock, leaving the 5VDC RELAY of its coil activated and its contacts will change This ignition will be permanent since the SCR is locked to deactivate it, you would need to open the circuit from ANODE TO CATHODE or remove the power from the circuit but since we are electronic we have to include this deactivation by means of a PULL UP to an NPN transistor that is with a negative signal will deactivate or It will open the circuit from ANODE to CATHODE.

3° The output to activate a motor or the coil of a three-phase contactor can be DC or AC voltage since we are using a RELAY that can support a voltage of 30VDC 10A or 220VAC 10A maximum at its output and using the imagination will depend on us What system to use to activate the motor either directly or by contactor.

WHAT IS A SCR?

SCRs are very important devices in the world of electronics and can be used for many things: from activating an alarm system to governing and controlling the ignition of power circuits such as: activation of inductive loads such as motors, ignition of lamps with high or low intensity or temperature regulation of a soldering iron to give very elementary examples.

It should be remembered that today in many household appliances, we find this wonderful device that, although it is not a regulator, behaves like a sinusoidal signal regulator.

We can find the SCR frequently and we can use it depending on the type of application that we need as a user, from lighting to sprinkler systems, going through the famous battery chargers that are undoubtedly important in the manufacture of these devices.

HOW DOES AN SCR WORK?

As we have already mentioned, there are many ways to do it, however we will mention some of the most important: we can do it by means of artificial light as long as there is incidence of light on the SCR or THYRISTOR junctions.

When it reaches silicon, the hole pairs of electrons will increase and thus this device will be activated.

(SOLID STATE PHYSICS)

In the industry, there are countless applications that require a certain amount of electrical power to be delivered in a variable and controlled manner, in which we highlight lighting, speed control, positioning, electric welding, and electric heating, which are considered the four most common operations worldwide. In industrial applications, it is always possible to control the amount of electrical power needed to be delivered to a load as long as a variable transformer is used to provide a variable output voltage.

Since the 1960s, this versatile electronic device called a small and relatively cheap SCR has been available, which does not require maintenance and its power consumption is very, very small.

Some modern SCRs can drive and/or control currents in the order of hundreds of amps in circuits that operate at very high voltages, generally in the order of 1000 volts. SCRs for this reason are very important in the field of modern industrial electronics.

• 1 SCR C106DG
• 2 BUTTON NO 4 PIN
• 1 JACK DC
• 1 LED 5MM RED
• 2 TRANSISTOR NPN 2N2222A
• 1 DIODO 1N4148
• 1 PC817 OPTOCOPLADOR
• 1 RELE 5VDC
• 4 RESISTOR 100 ohm 1/4W
• 2 RESISTOR 10K 1/4W
• 1 RESISTOR 220 ohm 1/2w
• 1 BLOCK TERMINAL 2 PIN BLUE
• 1 BLOCK TERMINAL 3 PIN BLUE
• 1 PCB

-VIN 5VDC

- Imax 0.030A

- output voltage 220VAC 10A

- START BUTTON

- STOP BUTTON

- MOTOR CONTROL OR THREE-PHASE CONTACTOR

I have developed the pcb in the EASYEDA program, an easy-to-use program and it has all the footprints of the components that I used for this project, how can we see the track of the PCB and the 3D image of how my PCB would look like in real life

10pcbs at $5 order them here www.pcbway.com

We thank PCBWAY for the professional pcb they provide us for this project.

GERBER PCB:

https://mega.nz/file/3QAlgJBR#BbRr3aWnTh2vfu1vhUFcXlQN5ryS9LzFFtV_V9aL_JU