I LOVE Teaching! It's ggod to know it shows. Thanks.

@@larsexplains3086 If you can do a real one both single phase and three phase and how it is wired in the real world it will be helpful.

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 anhd don't have much time to fit in a lot of videos. 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

Awesome! Me too!!! :-)

Thanks!

Thanks Juan!

Yeah I do 😆 Thanks

Thansk for the Props Samuel!

Thanks for the Props Samuel!

Thanks Tony!

Thanks Gerald!

Hi Autumn. Yes, that can be done. That’s using the contact backwards to how it is usually used in Ladder logic, and we don’t see that in Ladder Programming, but it is still fine as far as wiring and circuitry. Keep that type of thing out of Ladder Programming and because that is not allowed, you’ll get some people upset. I’ve never seen it in Ladder Programming anyway. : -) As far as wiring and circuit and you can use the contact backwards. There’s nothing electrically wrong with that. I have used contacts backwards to control a motor with two different voltages. I had the positive side of a motor connected to the common and 12 V connected to the NC, and 18 voltages connected to the NO. When I energized the relay, the motor got powered by 18 volts and when I deenergized the relay, the motor when back to running at 12 volts. Typically inputs come from a switch or sensor, so if you used to temperature switch as one input (Say connected to the NC) and a pressure switch as the second input (Say connected to the NO), and common to your load (Motor, lamp, buzzer, solenoid, heater, pump…). Then if the relay was in its normal state (not energized) the load would be controlled by the temperature switch and if the relay was energized the load would be controlled by the pressure switch.

You are so welcome Tyrese!

When a switch has a "normal state" it is in its normal state when it is not active. Any switch, like a push button will be in its normal state until it is pressed. A NO push button becomes CLOSED when the push button is activated. I wanted to highlight that a "Switch" as you commented is a switch and not a relay contact. IN discussion of a realy, we can say that the "contacts" in the relay are in their normal state when the relay coil in not energized. When a relay coil is energized the contact changes state and when the relay coil is de energized, the contact goes back to its normal state. The concept of a normal state is when the device (Switch or relay) is inactive. Any NO relay contact will ne in its normal state (open) as long as the relay coil is inactive. Once the relay coil is energized, the contact goers into its active state and becomes closed,. When the relay goes back to its inactive state, the contact will also go back to its normal state. IN this case the NO contact becomes closed when the coil is energized and becomes open when the coil is de energized.

WHen the power is cut to the relay coil, the Normally Open contact will go back to it's normal state and become open again. THat is because its normal state is open. When a NO contact is in its active state (when coil is energized) the contact is closes.

My pleasure Sean! Thank you for watching.

Good to know I'm reaching people all the way down to Califinia. It's a long way up from down there to Toronto Canada. I drove down to LA once when I was young. Took us 5 days of driving. Wa sa blast! You're quite welcome!

You’re not quite asking the right question again. 😊 I think you mean what current can you expect the relay COIL to draw. If I am not correct about that please let me know. If that is your question then the answer is, it depends on the voltage applied to the relay’s coil and the resistance of the coil. If you know both, you can use Ohm’s law to find the current. The other option is to measure the current drawn by the coil. Some relays are HUGE, and their contacts are designed to switch hundreds of amps. In this case, their coils are also very large and sometimes draw several amps. Other relays are tiny, and their contacts are designed to switch only small currents such as a few amps. These relays have very small coils that only draw milliamps of current. I hope that answers your question and also opens up new ones in your mind.

That was an interview question they asked me and I asked it the exact way they asked me. I’m thinking they want like a number of ohms?

@@jerrileethornton1291 Ha! If they asked me that exact question I would have asked “Can I get some more clarification because there are two types of readings, you can take on a relay? Is it the continuity reading on the contacts or resistance reding on the coil”? I think whoever was interviewing you should have been more accurate in their question. especially if the job was an engineering discipline, technician, or technology based, where accuracy in all things, including clarity of communication, is paramount. The other thought I had was they used odd terminology “Pull on” relay. I have not heard of a specific “pull on” relay, but there is a team called “pull-in” concerning relays. It is not a type of relay, but the voltage required to activate it and it is called “Pull -in Voltage” and “Pull-in Current”, but I have never heard of as “Pull on” relay. When you said that, I just figured you meant a basic relay, but maybe in your area there is a term that is like “shop talk” where a Pull on” relay is a relay with a Normally Open contact. (Shop Talk is, kinda like slang, where a term is made up and used in a particular industry to refer to something specific. This can change from region to region as well). If this is the case, they are probably asking you if you understand that the continuity of Normally Open contact will be “Overload”: or “infinite resistance” or just “open”. I think this all boils down to a lack of clarity in communication. I would be interested in knowing what they meant. If you get the job, please ask them and/or show them this and ask them to clarify what a “Pull on relay” is and what they wanted you to take a reading of. 😊 I hope you get the job!

Hi Paul. I’m assuming you’re talking about the contacts in the relay. Yes. I suppose a sea saw affect, image works where there is a spring on one side of a contact and the contact on the other. Check out this image in this article on Electromechanical Relays: ecstudiosystems.com/discover/textbooks/basic-electronics/relays/electromechanical-relays/ This video shows how the coil and contact works. It shows a cut-away of relay working: kzfaq.info/get/bejne/ob2hp7Zop6u4YYE.html

Ant 12 volt relay will do. Make sure you get one with contacts that can handle 10 amps. Any Automotive relay will do and they are designed to be weather proof and have mounting holes. Check out Digikey. THey have thousands and deliver the next day. Even for one item.

Thanks meshpal!

No. Knowone has ever told me that before. Ha ha ha ha. Yes, I get it all the time.

Yes, Tom is my cousin. Not really. Relays are AMAZING little 1 bit computers too!

Hi Jerrilee. I need to get specific and re-ask your question. There are two main parts to all relays. The coil and the contacts. The coil has resistance because it is an electromagnet and draws current and does work, so it must have resistance. The contacts are no different from the contacts of a switch. I think you are asking if the resistance of the NC contact on a relay was measured whould is show a reading of zero ohms? The answer to this questions is, Yes it would not read to have any resistance. Theoretically there is no resistance to any contact. If there were, it would steal energy from the power source, and get hot. If a contact is corroded then it will have a slight resistance and should be cleaned or replaced, but if it is clean and operating properly, then it should have no resistance. I hope that answers your question. Keep being interested and diving deep and asking questions. Bring them on!!!

I need to get specific and re-ask your question. There are two main parts to all relays. The coil and the contacts. The coil has resistance because it is an electromagnet and draws current and does work, so it must have resistance. The contacts are no different from the contacts of a switch. I think you are asking if the NC contact on a relay has zero resistance. The answer to this questions is, Yes. All contacts have zero resistance. Theoretically there is no resistance to any contact. If there were, it would steal energy from the power source, and get hot. If a contact is corroded then it will have a slight resistance and should be cleaned or replaced, but if it is clean and operating properly, then it should have no resistance. I hope that answers your question.

Yup. Exactly. A Normally Open switch's state is “OPEN” when it is in its normal state. When it is activated, it becomes “CLOSED”. Some people say that it becomes “NORMALLY OPEN”, but that is not correct. It is still called a Normally Open switch no matter that state. That is its name, but its state can be “OPEN” or “CLOSED”. A Normally Closed switch’s normal state is “CLOSED”. When it is activated, its state is “OPEN.