I just wanted to say Thank you. 20 yrs. ago a was a electrician. made mistakes and lost 14yrs to prison; change my life. I am a maintenance machinic and work with machines. Thanks to you tube, I found your teachings... I understand the way you teach. Thank you for doing what you chose to do; Help others!
Thank you so much, this was really helpful. My instructor put this on the board and had us transfer it to a breadboard with no explanation of anything except what an open and closed switch is. Then he had us wire that breadboard circuit to a pneumatic cylinder, wired to a dcv and 2 limit switches and expects us to explain it. freakin crazy! so this brought to light how a sealing contact works. thank you sir!
This was really helpful,well explained and entertaining! I'm an electrician studying PLCs in college atm, kinda needed a refresher on how hold on contacts work. Subbed and liked and found a new favourite channel. Thanks!!
Great to have you on board Cowboy! Let me know if you have anything you need explained and I'll try to fit in a video. Sorry for the 7 month late replay . ha ha
Could you just help clarify precisely what contacts you are presuming the L1 bulb is using on the Relay? Or is the bulb only in parallel to the relay but not being activated by it? Hope that makes sense. Thanks for your teaching efforts!
I think to answer that question for yourself, you should study relay contacts specifically. The reason I'm saying this is because the bulb is not connected to the relay coil, (that's the thing with the circle labeled R1), but it's connected to the contact that changes its state when the relay coil is energized.The bulb is in series with the relay's contact. Yes, the bulb is in parallel with the relay's coil and is remotely activated by the relay's contacts that change their state when the relay's coil is energized. The “relay” is made up of the coil AND the contact(s). The contacts are used to turn stuff on and off. The contacts are controlled by the relay’s coil. The coil produces a magnetic field that changes the stat of the contacts. This video will help you wrap your head around the basic relay, it’s coil and its contacts. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2yY3b350mhw.html
So could I use a holding circuit with a normally closed and normally open button to continuously activate and deactivate a solenoid that was pushing the buttons back and forth? 1. The solenoid in the off position pushes the “on” button energizing the relay which then energizes the solenoid. 2. The energized solenoid in the on position pushes the “off” button deenergizing the relay and cutting power to the solenoid returning it to the off position. Which in turn pushes the “on” button repeating the cycle.
Hey Gard. Answer is YES! Ha ha ha I LOVE the mad science! Old buzzers from the 70s and 80 and probably 90s used to be made a bit like this, but without the solenoids. Actually, I would imagine “used to” maybe not perfectly accurate. They probably still exist. There was a simple normal close contact that was wired in series with the relay coil. Energizing the relay coil would open the normally closed contact which in turn would shut off the coil which then would close the normally close contact which would then turn the coil on again and the NC contact would open again turning the coil off …… making a buzzing sound as the NC contact would constantly be jumping. They made these specifically with large normally close contacts that would vibrate loudly! Your solution takes an extra step and uses a holding circuit and an extra solenoid(s) and will work which would make probably an even louder buzzer that was maybe not as quick. I think if you were to put a capacitor in series with the solenoid you could create a time cycle. Even better, add adjustable capacitors and you can adjust the timing!
I think this video will explain how contacts on other rungs are associated with relay coils. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2yY3b350mhw.html
This was good. Way to keep it interesting. Has does the relay contact stay closed to power the coil? Why does it not just open back up to its normal state of N.O.?
The N.O. contact becomes closed when the coil is energized. As long as the coil is energized, the N.O. contact will remain closed. Either the Start button OR the N.O. contact can energize the coil. As long as one of these is closed, the coil will be energized. Because the N.O. contact becomes closed when the Start is pressed, the Start can be released, because the N.O. contact (being closed) is energizing the coil. If the coil is energized then the N.O. contact is closed which is keeping the col energized. The only way the N.O. contact will go to its normal stats and open is if the coil is de-energized, but as long as the coil is receiving power from the closed N.O. contact it will remain energized, which will keep the N.O. contact closed. I hope that explains why the N.O. contact does no go to its normal state.
@@larsexplains3086 I am tempted to say it like this: When we push a start switch, we push it with the intention of starting whatever it is we want to start. Sometimes when things get old, we hold the switch just a tat longer. If we play games and just touch a start switch to see if the device would start,,,, sometimes we fail if we are barely making connection. It is like we barely sent enough current to get the coil fully energized, bad old corroded contact etc. So when we push a switch, we push it to get the ball rolling. And that in itself guarantees that the other contact closes indeed. In reality it closes at the same time as the energized coil. And that is the story. This is photons traveling faster than your thought process. Can you say fast... fast fast.?
Great question Haze - I’ll tackle this on two fronts - Logic and Physical Attributes As for the logic or function of using a latched push button to keep the relay energized, the only issue is the relay cannot be de-energised form an external source such as a Normally Closed Stop button, or any normally closed switch like a temperature switch or a pressure switch .... or a normally closed contact from another relay. Also, if the power is disconnected from the circuit, the relay will de-energise and when the power is restored, the relay will stay de-energised until the Start is pressed again. If a Latched Start Button is used, the relay will energise right away when the power is restored. If the relay must stay energised for a long time, like days or weeks, it will degrade. It requires energy to keep it enertgised and therefore will produce some heat. Keep it ventilated and cooled if possible. If the latched push button can handle the current to the load, use it instead of the relay. If you do need a relay, that’s okay, just expect it to fail sooner than expected if it is energised most of its usage. The key to longevity is to keep it from getting hot. If you can do that it will last for years.
Yes and no. It is possible to use one NOPB to turn something on and hitting it again will turn it off, but to do that, three relays where two are used for holding circuits are required. This video (link at the bottom of this comment) may help you understand that a little bit. It is a video I did for one of my labs and it's not specifically about using one button to turn something on and then using that same button to turn it off, but it does have a similar function. In the video I show a circuit with a limit switch. The limit switch is connected to a counter. When the limit switches hit once and released light one comes on and then when it is hit again and released like two comes on. What you can do is build a similar counting circuit that will count the event of the push button being pressed and released (instead of the limit switch closing and opening) and then once the push button is pressed again, it will terminate the first count. In this example R3 documents the first time the limit switch is closed. I would use that relay to turn on light or whatever you want to turn on. Then R4, which is called the done bit, energizes when the limit switch is opened. If you wish you can then use R6 to terminate R3 which would then of course turn the lamp off. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-drlP8QDGreQ.html
Hello Ahmed, This is a video on Ladder Logic which uses relays and their many contacts to create logical control circuits. The symbol labeled R1 is the coil on the relay and each contact, (the things you are referring to that look like capacitors), is a contact associated with that coil. Therefore R1-1 is a normally open contact associated with the coil R1, and the contact R1-2 is another normally open contact associated with the coil R1. The contact that look like capacitors with lines through them, are Normally Closed contacts. Here is a link to my first video on Ladder Logic “Introduction to Ladder Logic”: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2yY3b350mhw.html In this video I explain all of the above. Thanks for asking!
In our lab at Humber College we use a Variable DC Power Supply. Typically, in industrial application a dedicated 24-volt power supply is used. Relay Ladder Logic can also be used in vehicles (Cars, trucks, Recreational Vehicles, Heavy Equipment Vehicles, Boats …) and 12-volts and 12-volt relay and components can be used. If you have a bunch of relays and want to build some of your own circuits for a DYI or just for fun, you can get your hands on a 12-volt Lead Acid battery from any vehicle, even a motorcycle and find some 12-volt relays. Or if you have AC power, you can use a desktop computer power supply. Almost all of them have 12-volt and 24-volt power available.
Relay latching circuit basically. The only issue is your drawn schematic. Relays have a power input and output CONTACTS (NO NC COM). You draw them as one LINE in this schematic. I fully understand how latching circuits work but your method of drawn schematic is leaving this out. I recommend you at least show an ACTUAL CIRCUIT IN USE to help students understand in detail. By leaving this information out they will assume the relay powers itself with out PROPER CONNECTION. Not intended to negative feedback but constructive.
Yup, you are correct. As you know many relays do have both NO and NC contacts and they do not have to be drawn the way I did it in this video. In “wiring diagrams”, all components of the relay are represented so you will see both NO and NC contacts on the relay module and the circuits are drawn more along the lines of where the components are or follow more of how they should be wired. The focus of my circuit drawing is more on Logic Control and is called Ladder Logic diagram where LINEs have each their own logical function. Ladder Logic is more like a programming language than a wiring diagram. Each “rung” is like a LINE of code that will contain inputs and outputs. The outputs are always the last component on a rung and can be the relay coils (and other outputs - motors, lights, buzzers, solenoids…). The inputs are always before the outputs and the make up the logic controlling the outputs. The inputs can be other relay contacts (NO and NO) or switches. The main function of drawing circuits this way is to develop complicated control circuits. Ladder logic is mainly used in programming PLCs and in other control simulation software but is also used to create complicated control circuits with relays. Ole Elevators used to use only relays for their control circuits which were developed in Ladder Logic.
You are the second person to ask for info on Three phase wiring. I’ll see if I can fit in a video on that. I will include the difference with single phase wiring as well. I will use a motor example using my college’s three phase motor control panel so you can see a tangible example, and the detailed writing. I probably won’t be able to tackle that until March. Sorry, I just do these videos for fun and to empower my students. You can always register to study Electromechanical Engineering at Humber College in Toronto, and I’ll teach you in real life hand on! 😊 Here is our program’s link: appliedtechnology.humber.ca/programs/electromechanical-engineering-technology-automation-and-robotics-profile.html Thanks Keep being interested and diving deep and asking questions. Bring them on!!!
@@larsexplains3086 thank you very much for the feedback. I would have been more than happy to apply for education, but the fact is that I live and work in Sweden. and then it will be difficult for me to study in Toronto, but if you have a distance learning course, I can absolutely do it instead.
@@FA_56 Sorry, we're very hands on, so not we don’t have remote learning, but I am happy to help if you have a specific question. I think it’s so cool that I have people watching from all over the world! Thanks for watching! I LOVE old cars and I think you do too. I have had several American 60s and 70s cars. Currently I have a 1977 Lincoln Continental Town Car.
Hi Kevin. Thanks for this great question! The answer is in understanding how the inside of a relay module works and what the symbol for R1-2 represents. The contact R1-2 is inside the relay module and is magnetically coupled to the relay coil R1. This video will help you understand how that works. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-x_a_6VhQJrU.html
WOW! Thanks Dude! We're always accepting new studenst into our awesome program. Check out this link and sign up for our program! I know the Program Coordinator really well!!!! appliedtechnology.humber.ca/programs/electromechanical-engineering-technology-automation-and-robotics-profile.html