What is a Contactor and How Does it Work?

[@jesperlowinger]

Hi im 23 y old from sweden. Currently im rebuilding a mig welder, everything except the transformer is getting replaced. Now i need to control gasvalve, Wire feed speed and transformer with the mig torch as the main switch. I have a plan, but i just want to give you props for your work. Always good clean easy to understand information and no BS. Keep it up! Cheers from sweden / Jesper

[@mefistafree6031]

i watch you to learn English i am an electrician and this channel really helpful to improve listening skill and increase vocabulary memory when i hear a vocabulary or idiom that i never heard before i can guess what do you mean because you are talking about my job when i was an apprentice i was in trouble with contactors and relays

[@albertrodriguez5598]

mefista free glad you’re not making excuses acting like it’s impossible to learn English like 90 percent of ppl who need to learn English for a good career

[@cuper4295]

Thanks for all the good info. Here is a slightly different way of thinking about the same things you've said. Spoiler alert, point 4) is the real differentiator between a relay and a contactor. 1) Both relays and contractors are passive power amplifying switches. On a relay, the control currents are typically measured in milliamps and the voltages are typically < 24 volts. The output currents are measured in amps and the voltages are < 240 volts. On a contactor, the control currents are typically measured in 100s of milliamps and the voltages are typically < 120 volts. The output currents are measured in 10s or 100s of amps at voltages of 120 to 600 volts. 2) Both relays and contractors can be used identically in logic situations to implement boolean logic as part of your control system. 3) The main thing that distinguishes a relay from a contactor is how they are made inside. Both relays and contractors have arcing problems (which erodes the points) when the points of the device open and close under load. In a relay, "normal" material and switch design can be used and still provide a life of 10s or 100s of thousands of operations. In a contactor, "special" material and design must be used to provide a reasonable number of operations before the points wear out. 4) A second differentiator between the two is how the internal connections are made. In a SPST relay, there is one set (pair) of contacts and the armature (the part that moves and actually makes contact) is live (i.e., is connected to one of the output terminals). In a SPST contactor, there are two sets (pairs) of contacts and the armature is dead (i.e., is not connected to either output terminal). When a contactor is activated, the armature causes both sets of points to contact and the output current then flows through the armature. But the armature is never directly connected to either output terminal. 5) Point 4) is driven by power design considerations, but also provides a level of safety for high power circuits. This is how an engineer (at least this engineer) thinks of these things. This electrical engineer also put himself through college working as an electricians assistant and still maintains a high level of respect for master electricians who are dedicated to their craft.

[@Huskyresqr]

you left out one of the most important roles of contractors, especially those used in industrial machinery situations.....if the machine loses power...for any reason....the (non-latching) contractor will prevent the machine from restarting when power returns.....working around rotating equipment, this can be life saving......

[@dosepulveda1]

@Tom Garbo lock out tag out baby

[@urano4810]

@@dosepulveda1 preach

[@user-yh4kl3hx2o]

Serious knowledge there man 💪🏽💪🏽💪🏽

[@struckanerveagain1428]

You should give your contractor a raise for doing this.

[@MicahFunk]

Back in the eighties, when I was learning about this, I was taught to look at the contactor like a knife switch or door. When the knife or door is closed, then, it connects; whenever the knife or door is opened, it disconnects. 🚪🤓

[@Batman1krr]

First clear and understandable breakdown. I can confidently talk about a contactor now.

[@MatthewsDre]

Best electrician on youtube👷🏻‍♂️

[@Clubskunk]

LEO 1984 100%

[@sekiko7183]

Besides Electroboom. Both are good.

[@stevenpersinger6577]

wow. anyone that calls themselves electricians. should already know this stuff. he is a great electrician. but nobodys the best of anything on youtube. dont church it up

[@goaliedude32]

My favorite use for contactors so far were in an autobody shop that had 12 garage doors all on automatic door openers. When the technicians (or anyone) drives up to the garage door, the door sensor opens the door and they drive in without getting in/out of the vehicle. At the end of the day when they close up shop, the shop light switch also feeds to a contactor that interrupts the garage door circuits. When the lights are off none of the garage doors will open at all. There is no power going to them, cut off by the contactor. It's not really that complicated, but I thought it was a very clever solution on how to lock 12 garage doors easily with the least amount of effort

[@stuartlenk9436]

That’s smart

[@artherrera4521]

Ii>ol

[@chadyork7352]

😮😊xea

[@chadyork7352]

S90e03c9×😊÷$'was quietly

[@chadyork7352]

😊e9❤experience 😊qs90as 😊😮qq

[@KevinCoop1]

Dustin, Well done again! A few comments. Relays 10 amps and below, contactors 20 amps and up. Mechanically held contactors have coil clearing contacts to cut power from the coil once changed. NEMA(USA standard) (black) rated contactors good for 100,000 operations, IEC(European standard) (white) rated for 10,000 operations. I hope you do not mind the additional information! I hope electricians aren't really connecting coils without checking the voltage first! Respectfully, Kevin

[@hey.you.in.the.bushes]

What do you use between 10 and 20 amps?

[@odellcooley5324]

Great video. I watched years ago when i was binge learning all electronics. Back again to the same vid years later for my first time needing a contactor. Thank you.

[@halidespecialist8562]

These vids are a lifesaver. I'm a residential electrician trying to figure out industrial controls at this new job.

[@robertoperez4391]

Hi, I really worked with enough mechanical and non-mechanical contactors. for mechanics and had to use relay to be able to unlach. Today I tried to convert a mechanical one like the one you show in the video so you don't have to use the relay but when it was connected it was not fully connected, it just jumped continuously, I think it is coil separation. I returned it to its normal state and it worked perfectly

[@mrgfcwelding4479]

I've been watching video after video about contactors and relays. You are the 1st to explain the fact that a regular light switch can be used to send the signal to activate the contactor and deactivate it.I live in Lima, Peru and don't speak a lick of spanish. Just trying to find 3-way and 4-way light switches has been a pain.

[@morisn]

Very down-to-earth explanation, dude. I like it. I actually studied electricity in high school at a time when computers were a luxury item in schools (not even homes, but schools). So I am reminiscing this knowledge buried in my brain for decades because I need it now. I'm glad I found this video.

[@DavidR8]

Well you just completely demystified contactors for me, thank you!

[@arthurmoore9488]

The lighting contactors and conversion kits were new information to me. So, thank you.

[@dylanmartens2282]

I really enjoy your videos, makes me want to be an electrician again. I took electrical in high school but once I got in the work force I couldnt find an apprenticeship for it. Ended up getting into hvac with the promise of being apprenticed but that is turning into a shite show. I been working here as a helper for 3 years. I think its time to start looking into being and electrician again, what I originally wanted too be. Thanks for all your videos man. A fan from Winnipeg Canada!

[@VoltsAnBolts]

That happened to you in Canada? That wont do. Go to your local IBEW and ask about apprenticeships, you may have to do a foundation's course but in Canada getting an apprenticeship should be basically done for you. Talk to whatever school near you hosts trades programs, your local IBEW or start phoning every electrical company in the city. Good luck!

[@kelsie9912]

Thank you so much for this video - this really helped me understand exactly what a contactor is and how it works! Great video and I love that you explain is so simply!

[@chadyork7352]

Sfa😮vc

[@danielliu9947]

Really clear Demo, love to see the parts take off the contactors.

[@marktony4842]

Great video I'm a 1st year apprentice and we were installing these yesterday I'm omw to work right now trying to learn I asked what they were and the guy showing me said it's so the lights can come on at the same time. Immediately wanted to know more about them

[@liamwelsh5565]

I'm a first year apprentice and every time I'm introduced to something new that's a little complicated, the master electrician I'm working under always explains how it works and what it does like shit. So when I get home I just watch you to see what the hell he was talking about.

[@paprikadesign3339]

I just started my apprenticeship at a switchboard company and this video (as all the others from you) is extremely helpful. Thanks heaps!

[@katuraysalad]

Thank you very much for this video

[@rocky_rocker_1235]

Yeah. You should do a video with light switch as digital field device to simulate a pressure switch , temperature switch , level switch, flow switch, etc. Then use light bulbs simulate motors, heaters, magnetic 24VDC/120vac valves, status indicating lights/feedback, etc. Then throw in some timer relays too. Like if the system doesn’t see pressure at certain time then have relay pick up a light for a fault. Then you can design and draw basic digital paddle logic control circuit for young electricians. Then they can see how the current flow throughout the control circuit system through and how the basic automation works. Sweet video man. You’re giving people free knowledge so they can put food on their kitchen table. 👍 keep them coming.

[@albertrodriguez5598]

You know you love electrical when you call a contractor “awesome” and “badass” lml

[@JesusMallari1959dec28]

I like your gestures and your actions when explaining on your topic, you are so energetic and what I can see is you are so very professional. We have similar contents and I compare myself to you as I am only a beginner student. I hope my channel will be like yours even just a little bit so that my channel can help others like yours. Thanks for this very professional tutorial video sir.

[@47vulcanride]

Very helpful for me the amateur. Good job of describe the basics. Thanks

[@ChowZeb]

I'm a mechanical engineer and found this video helpful.

[@mr702s]

I'm doing a 50amp emergency shutoff for my server rack. A mechanically held latch for it makes the most sense since I would need to shut off more than 1 circuit.

[@glennmcgurrin8397]

For both relays and contactors the time things get really confusing is when you have a system (typically safety related) where the contactor or relay is normally energized unless some condition exists. Basically reversing the no and nc roles, generally so a loss of power or break in the wiring also triggers the safety action

[@azarul94]

this knowledge is good enough for me. much appreciated, thank you brother

[@brandonharris6230]

Awesome video you are very good teacher! This info helps tremendously thank you keep up the good work! 👍

[@jonanderson5142]

Hey Dustin Great Vid as always .Teaching this old dog a new thing or 2..lol

[@elc2k385]

I watched all these videos several months ago, I mostly forgot them, but I am going to rewatch them. Watching this video the second time around, it makes more sense.

[@oumartellydiallo6411]

Nice video! I'm learning English But have got all your explanations For the contractors and relay from to day onwards I will follow all your videos Incha Allah! I want to learn commercial and industrial electrical wiring

[@CAMMEDcivic]

Had to refresh my mind, thanks again Dustin! 💯

[@73elperro]

Excellent video,really easy to understand,please keep making them.

[@CristianZatonyl]

Great video! Can you do automation?

[@dankamp2872]

Ha, I saw the title and my answer was "Very, very slowly." Then I looked again and saw that it says "contactor", not "contRactor."

[@RingleberryMcFinklestein]

Love it. Great as usual. Thanks.

[@alvarobarboza5730]

great content. good music in the opening and closing segments. thank you.

[@crisevansdiwa6433]

thank you very much.. its helps me a lot :) your explanation is great, much appreciated..i will watch your other videos when i have free time to learn more...

[@bernardchangtyseng7202]

Thanks bro,,, by far the best break down.

[@nhzxboi]

Also, if you enjoy owning your finger, never get in the habit of closing the contactor by pushing on the center. Never done it but have seen it especially on a "untried" circuit. There is the potential to blow your finger off if the load is shorted. Beware, take care. Don't do that. Also HP ratings. 30A resistive, 9A HP rated is pretty typical. Motors are a beast.

[@raymondgarafano8604]

w hen us ed to operate an electric motor, usually with overloads, you have a 'Mag starter'. pressing the ON energized the coil and pulls contacts together, BUT if the motor is overloaded either a magnetic coil/ or heater coil opens a switch through which magnetic contactors coil's current goes through and the circuit is opened, contacts to the motor are opened and the motor stops. it is the current the motor draws that passes thru the overloads. If motor draws 15 amps, at full load then, with a greater load more current is drawn and that extra current drawn causes more magnetic pull or heat on the overloads that causes switches mated to overloads to open the contactors coil current.

[@theotrotchie]

I have to say, I get this guy. Speaks my language.

[@Edgardocelectric007]

After 35 + years in the trade, nothing scares the shit out of apprentice more is trying to troubleshoot a 12 pole contactor with all the wires etc. and yet it’s very easy to check

[@Steve-fz4it]

Fantastic information! Thank you for putting this together. Keep up the great work!

[@Mopardude]

In the next video on this subject can you talk about the use of piggy back modules on contactors?

[@javiergiraldez1647]

With contactors and relays you can do a lot of thing, show lighting, automatic transfer switch for Utility, Solar, Generator to house circuitry. Schneider is the best brand to do it.

[@HulstylerOne]

Great video! Thank you for the lesson

[@CrimFerret]

This is an excellent explanation. You didn't mention anything about the current draw for the coil, but I'd imagine it's relatively low. That also explains why one would use a relay to control a contactor. If your control signal were at digital logic levels, say from a control board, you'd need to use a relay to switch the higher voltage that controlled the contactor (not to mention keeping any voltage spikes away from the much more sensitive circuitry).

[@joerostkowski7313]

Donut, phase monitor ,he just 101 contactors, work on not leaving your scrap on top of ceiling tiles sparky!

[@gokblok]

The phrase that clicked for me was "using low voltage to control high voltage". I didn't understand the two "sides" of a relay until someone said that to me. Also, it might be helpful to use a meter and show continuity (or lack thereof) when explaining NO vs NC contractors.

[@kevinmart6376]

Very easy to understand great content

[@DangerousTv1]

Great video. I'm currently working on a project where there is an existing 60 amp lighting contactor being fed from a main panel and has the load side of the contactor feeding a sub panel they're using for lights only. It's a duplex apartment and during renovation a lot of wires were cut including the "master switch" that shuts off every light in the apt. I traced the master switch and it is actually wired to 2 small guage leads in the contactor. I'm assuming that's the coil which will close or open the contacts. I'll give this switch its 120v and see if it will actually control the contacts because as of right now, this contactor is normally closed and every switch would need to be controlled independently.

[@goaliedude32]

I understand everything you said. I failed to understand why it would be set up like this.

[@IsmaelTerrenoIBunkerteam]

Amazing job ! great video! thanks for the explanation

[@basitoe]

I have a lot on this channel thank you brother God bless you more.

[@ElectricianU]

thanks for watching my friend!

[@thegodofpleasure]

This is a very helpful and informative tutorial. Thank you. Can we have the follow-up supplementary videos soon please?

[@shelvins1841]

Awesome vid. Great info, thank you

[@LonelyLeo100]

Good video. You should have mentioned for the beginners how to test if the a contact is NO or NC if it is rubbed off do to age. Not every one or application is going to have brand new contactors or relays to work with.

[@carultch]

De-energize the control circuit, and ohm-meter the line and load terminals of each phase. If you get zero ohms, it is normally closed. If you get infinity ohms, it is normally open.

[@lennoxbourne6]

Thanks very much for he explaining how these work

[@CrToloss]

Always the BEST.. ❤

[@jodystradesstuff5048]

I think this topic would have been really helped by you having your multimeter handy in continuity mode, and show the NO/NC difference. Even so, just the verbal was a great overview!

[@charleskosmin1030]

That's was really informative, thanks

[@gcg9056]

great communicator - thank you

[@ProfRK-on9fp]

I also watch a video about electrical circuits and power controls in English like this to help me in the subjects I teach at the technical high school with bilingual teaching (Portuguese / English), mainly with vocabulary and pronunciations - greetings from brazil

[@Clubskunk]

Keep up the videos! Very informative

[@robertobanda6094]

Thanks for the info. Ive learned a few things form your videos.

[@toddwoodhouse9162]

This was awesome! Thanks!

[@raymondkb2nzo788]

Very helpful thanks

[@morelightpm457]

Great job on this video

[@topallielton]

Hey Thanks, whats the rule for the side you put the line & load on, I understand its doesn't matter, or does it??? THanks

[@carlosbarron5725]

Thank you!

[@shanesmith8420]

Self contained switch is the proper name for your dead end threeway

[@markf.r4538]

Thanks for these awesome videos

[@brianmcdermott1718]

Super great info. Thanks

[@stevekeys262]

Great work!

[@JerryAtat]

Thank for sharing👍👍👍

[@yadimirtorres2207]

Smart dude ..love ur channel

[@javierferrer4634]

Very nice video thank you so much!

[@Linux4Ever2011]

Totally appreciate your effort 😊

[@ElectricianU]

Thanks my friend!

[@manwells7019]

Well done

[@hg2.]

Another good one - thanks! I first heard about contactors in HVAC videos -- specifically sending a low-voltage/low-power thermostat signal to a high-voltage/high-power compressor circuit. Contactors are great because that way, you don't have to send 240 volts through the thermostat on your wall -- 24 volts will do for that. Keep these great vids coming!

[@John-zz5gt]

Thank you sir

[@davidadame1313]

if i wanted a contactor to be controlled by a photocell or time clock, how would i wire that? power to the photocell first and then the contactor?

[@dsugrim1763]

david adame Correct 👍

[@goaliedude32]

What load were you trying to control? They make photocells/time clocks that are rated for loads. I've only installed contactors for complicated scenarios or large loads. If you have a normal load you can find a single device to control it. No sense on installing a contactor and photocell when you can just install a photocell

[@zachwalker3288]

Maybe a video covering a high leg system?

[@carultch]

The purpose of the high leg system, is when you have primarily 240V loads, whether single phase or 3-phase, and you still want 120V loads to be available for lighting and general receptacles. It works best if the KVA of the 120V loads is a small minority of the total load. If you use a 120/208V wye system by contrast, you loose 13% the voltage that would otherwise be available to the majority of your loads. Each phase is 240V away from the other phases, but something special happens between A and C. The transformer winding that produces phases A and C, is also centertapped to produce the neutral. This is where you can power your 120V loads. Consequently, the B-phase is 208V to neutral, and for all practical purposes, don't count on using it for any single-phase-to-neutral loads. Reserve the B-phase for 3-phase loads, and phase-to-phase connected loads. Most single pole breakers are slash rated for 120/240V, which means 208V to ground would not be allowed. You'd need a 277/480V panelboard, to be able to use the high leg-to-neutral. It is a requirement in the current NEC, that the B-phase is the high leg. It used to be that the C-phase was the standard for the high leg, and you may find that in old services. Some utility meters may also require a C-phase high leg, even if the rest of the building is B-phase high leg. The recommended practice to working with one of these systems, is to produce a single phase subpanel, off of a branch circuit on phases A and C. Avoid putting your single phase loads in the main panel, and strategically put them in the single phase subpanel. Put only 2-pole and 3-pole breakers in the main panel.

[@Dat_Guy1989]

At about 9mins in the video you speak about mechanically (latching) contactors. Can you control latching and unlataching mechanism with the same control circuit or do you need two different circuit to lastch and unlatch? Any help would be greatly appreciated. thx man

[@dsugrim1763]

Another Great very Very informative

[@hauvu1989]

u the goat bro

[@awatchman5945]

Need info on wiring a single pole 480 contactor with a photo cell AND a HOA switch. A diagram would be awesome.

[@rickalejandro7720]

You are the man👍. I would work for you

[@นกกระทา-ซ4ญ]

You said the 4 pole contactor was rated 30 amps and can not use more than that. But if you use it for single phase and use 1 and 3 together for Live wire and 5 and 7 together for the other wire than i would assume it can do 60 amps? Or pole 1, 3, 5, 7 together on Live wire and a second contactor for the other wire then i assume i can do 120 amps. I have never seen anyone mention this kind of wiring a contactor so what do you think?

[@LuisGarcia-zj4pf]

Great video, could you make a few about the nec codes?

[@marcomoreno3504]

How do you check if you bad contactor . I have one not sending voltage to next to next one i have it series .

[@hugimelo]

awesome videos..thanks

[@willhenderson229]

Wish you'd make a video with single pole double throw diagrams for a 3way switch using contacts.

[@jacknedry3925]

Have an auto start generator set with a normally closed contacter. How? Have a single pole NC contacter on the mains to keep the circuit open, so when the power cuts out the contacter closes a circuit signing the generator set to start. There are other mechanisms, circuits, and systems that will most likely be implemented too. Perhaps a “generator ready” contacter to signal that the current is stable. A generator off mechanism is a must though

[@chadgerman8173]

Great stuff

[@antoniobarron2956]

Very good into detail explanation but there was never a close up of the camera to really understand what you are talking about.

[@jamesjoseph8011]

Great observation Antonio. I noticed that also. He needs to improve on his presentation.

[@ceeball9525]

Hey Dustin, so when you speak about coil. Is this where you usually land the timer switch? But the line side from the panel still gets landed on top of the contractor then load to the bottom? Thanks for all your videos!