What is the Purpose of the Main Switch?

The Main Switch is the onepart of a control panel which has a large impacton progressing a project. We’ll go into that later,but for now, don’t switch off, this Post is going to be electrifying! And before we get into the video, I’d once again like to ask you to comment if you find it useful.

This really does help us to dream up more concepts and exciting videos tocreate for you in the future. When we look at the panel from the outside, one of the first things we see issomething labeled a “Main Switch” sometimes called an isolator.

What it does essentially is applying or disconnecting thecontrol panel from the power source. The control panel we have here is powered by a 3 phase supply, which is rated at 415 Volts AC.

This, in turn, can be used within the panel to power single-phase devices, or 230 Volts AC by using 1 phase of the 3 phase supply. We can also use transformers toconvert AC voltage to DC voltage to power our 24 Volt and 12 Volt devices we briefly covered in theControl Panel overview.

So the main switch applies ordisconnects the 3 phase power that we have in the control panel. We usually designate the 3 phaseswith the following labeling system; L1, L2, and L3 are the3 phases of the supply. “N” is the neutral wire. The neutral wires' purpose is toprovide a path back to electrical ground to complete the circuit.

When I put the main switchin the ‘0’ position, it indicates that the isolatoris in the OFF position, and it will disconnect thepower flow to the control panel. When I put the main switchin the ‘1’ position, it indicates that the isolatoris in the ON position, and it will enable the powerto flow to the control panel.

On the back of the door, this switch has wires connectedto the terminals on the switch. You see the identifiers on the cableL1, L2, L3, and N? These are connected to the mainpower coming into the cabinet labeled L1, L2, L3, and N also. The other side of the switchconnects to the distribution unit.

From here one of the phases goesto power these two power supplies; one phase comes here and goes to the input for this power supply, the 24 Volt DC one, and for this power supply,the 12 Volt DC one.

The input to these two powersupplies can be 100-240 Volts AC. Inside, these power suppliestransform the AC signal into a DC voltage output, 24 volts one case,and 12 volts on the other.

This DC power can then be usedfor devices in the control panel, or for devices out in the field too! Since we are using 1 phaseof our 3 phase supply, our input to these two power supplies is around 230 Volts AC. The rest of the 3 phase powergoes into this terminal block and can be used to power the devicesthat work with 3 phase power.

So the single-phase power, powers these supplies and we connect the3 phase power to these terminals here so that we can use them with devicesthat work with a 3 phase supply. When we install thiscontrol panel in the field, the 3 phase supply will be connectedto the top of these terminals.

Then through this trunking, they are going to be connected to thetop of the main switch that we have here. Through the other end of this switch, the terminal blocks are going to beconnected to this terminal block.

From here one phase goes hereto power the power supplies and then all of the 3 phases also willbe connected to this terminal block so that we can use them to power thedevices that work with the 3 phase supply. We have the 3 phase supplyconnected on the bottom and the devices can be connectedto the top of the terminal blocks.

If we put the main switchto the ‘0’ position the incoming 3 phase supplypower will be disconnected, and that shuts down thewhole control panel, including all of the devices thatwork with 24 Volt DC and 12 Volt DC, and also the devices thatwork with 3 phase power.

That’s it for this video! We are starting to get into a bit more detail about the inner workingsof the control panel now, and thanks for staying with us so far! If you’ve understood everythingwe’ve covered so far, you are now well on the way tohaving a great understanding of how a control panel works, add to that now the main switchfunction, and why we use them, you’ll soon be powering on your future.

They are experts at control systemdesign and industrial automation. They have a team of world-classautomation engineers and have been designing and implementingindustrial control systems in different industries for many years. If you want to get in contact with them, youcan check out their website at pro-control.nl. That’s pro-control.

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