Good job of explaining mag starters. You are so right - understanding the principles behind starters are a powerful tool to have.

Keith at 22:24 you say that the switch (2-3) on the motor starter is Normally Closed, that should be Normally Open. The Blue - Black wire on the motor starter are only connected when the coil is energized. Great diagrams, and good explanation. I had never looking into a motor starter before. It is really a latching relay with thermal overload protection. Understanding how it works is the way to go.

Well explained I have been an electrician for 50 years , that explains things very succinctly.

Good Job ! Both the IEC (your "new style") and NEMA (your "old style") starters have extra Aux contact for alarming, signaling, or whatever you need for your control. In the heavy duty industrial applications I was involved with, we used NEMA due to them being oversized and their ability to withstand multiple overload conditions without damage.

Nicely done Keith. Having worked in a shop before I wired up a few machines with the electricians. This was when I was about 18~19, so I was just learning stuff. You did a much better job of explaining it than they did. They were more "yea, just wire it like this". I was "WHY!?!", they were "Because it will work this way". I kind of wondered if they actually knew...LOL

Thanks for taking the time to explain this I know you need them on a big motor but I never understood how to wire them or how they worked. Thanks again...

I’m an industrial tech apprentice going through schooling, and I understood this explanation a lot better. Awesome job thank you!

Thank you for putting this out. It is exactly the information i am looking for!

Keith, thanks for a great explanation of how all this stuff works. I agree that it's really important for those of us "playing" with older machines to understand how things work and not just try to get by with "connect terminal a to terminal b, then c to d" style of working. When you understand how it all works, you can confirm for yourself what will happen when the power goes out or there is an overload. If you don't understand how something works you really don't know if it's safe (electrical or otherwise). This is not easy to explain and I think you did a great job. BTW, for those accomplishing the same task with a VFD, things are done a little differently, but all the same safety considerations need to be taken into account.

Awesome great way to start my morning . Thank you Keith for the wonderful videos explaining how to do things !

Great video Keith! You've demystified motor starters and stop-start pushbuttons for me!

Excellent video Keith.

Up to my ears in that myself. I’m learning more about phase converters and motor starters than I ever wanted to know. However, it’s absolutely essential. Thanks, John

Thank you for keeping it simple! I can finally wrap my head around this concept now. This is great for visual people like me....and thanks for the drawings with different states of the circuit. Super helpful.

If you only want to know the wiring diagram, this ain’t the channel for you. Mr. Rucker is an educator and an entertainer who provides the interested parties a platform for both. Love your work, Mr. Rucker.

That was great. Very informative and useful! Thanks, Keith.

Thanks for sharing this Keith. Very well explained and simplified

Thanks, Keith. I'm restoring a DeWalt GE and this helps.

Excellent video....clear explanations of the circuits.

Well done Keith, thanks for taking the time so it could sink in.

Great job Keith, useful video

Motors need to be “over fused” because they take large amounts of current to start, but they also need to be protected from long term overload during use. The “heater” over current device builds slowly (relatively) and accepts the high inrush of current during starting from a stoped rotor but will trip if a motor is drawing much lower current (relative to the brief starting current) that is higher than its rating. AND: series all your STOP buttons, and parallel all your START buttons if you have more than one start/stop station.

Always love your videos Keith

Great job Mr. Rucker!

Great tutorial! Thank you.

Thank you for sharing. Enjoyed.

That was a great explanation of the motor starter. Sure wish this was on KZfaq 5 years ago when I converted my 10EE to modern electronics. Thanks!

Thank you. Thank you. Thank you. i really appreciate the side by side demonstration. I never really understood the overload relays and how they tied into the control circuits. Great down to earth explanation of it all.

Thanks Keith answered alot of questions.

Great job Keith.

Great explanation.

My god man....your workshop looks absolutely fantastic. 👀👀

Great video simplified for beginners in control power. Thank you

Thank goodness for instructions that come with switches. I do this type of thing so infrequently I have to relearn it each time. Thanks for the video.

Great job Keith 👏 👍

Great explanation!

Most excellent bit of information.

The great thing about this channel is that I can understand every word he is saying unlike the Indian dialect videos. I am not saying the indian videos are not correct and I am not taking away from the work put forth in those videos. I just like a video that I can understand with proper english without the accent.

great job explaining it

Serendipitously I discovered that by dragging the video slider back and forth you can animate Keith's switch drawings like a flip sheet. Some of the positions are a little obstructed but done on purpose I think this phenomenon could be used to great affect in future videos.

It probably should have been mentioned that there are different sizes of starters for different sizes of motors. One of yours was marked "Size 0" which is rated for up to 3 HP when operated at 230V (or 5HP at 460V). There is a smaller size, Size 00, good for up to 1.5HP at 230V as well as larger sizes up to Size 6 for a 200HP motor at 230V. You can find sizing charts online.

Great video. Thank you

Thank so much for good explanation

That was a good explanation of a contactor circuit with overload protection. One option that I have encountered on our heavy duty 480 volt pressure washers at work, is a rotary on/off switch in lieu of push buttons which I do not care for. Our equipment has a time delay in the lock circuit that won't operate unless there is water pressure present at the pump. It's just a more complicated circuit. There's a good possibility that the machine could be turned on when a power disruption is resolved. I hope in your next installment on this machine that when you begin to discuss wiring it up that you can discuss horsepower amperage draw in relation to wire gauge, and phase rotation, which can be changed from changing any two legs of the 3 phase motor in one of 4 places. It can be done on L1, 2, 3, on the contactor or on t1, 2, 3 of the same. It can be done on the electrical breakers, or in the event of a plug, it could also be done at this point. Again, thanks for the well thought out discussion on this safety feature. On further point I would suggest is that if/when this shaper is plugged in, that the breaker or disconnect box be turned off before plugging it in as high voltage does have a risk of arcing when plugging in, even with a contactor deactivated. The company that we contract with has made this a work rule.

Great info thank you.

Great video I setup my air compressor roughly that way. No overload. Put a 3 phase (it's what I had on hand. Didn't need to be a 3 phase switch) magnetic switch in the 1 phase 220v line. To activate the switch I use a 110 wifi smart switch. Didn't want the compressor to have power on it when I wasn't home and manually tripping the breaker is impractical. So I walk in the shop and tell "Google to turn on compressor". Smart switch closes its contact witch sends 110v to the bigger switch with the 220v line and closes that contacts witch makes the compressor work normal as if it had power all the time. Saves money and I don't have to worry about the compressor contacts sticking closed with out me there. It has happened before..

Thank you for video.

I liked the way you teach

I thought you said you were not an electrician. That was a good explanation. I am now working on an old industrial oven control that I plan to use for a foundry furnace. Circulator and exhaust fan, air flow switches, purge timer, flame sensor, pilot light, ignition and main gas. Lots of interlocks, timers and motor starters.

You are such a great lecturer sir excellent explanation and spectaculous voice I have really enjoyed your lesson.

Kieth you are a good man

thanks keith, it's a tricky concept and that video is going to help a lot of us.

Guessing we will be seeing a video on the metal planer motor starter soon 😊

Good video

I've got an old HUGE (200LB) Baldor Bench Grinder at a factory maint. shop auction that had the push button start/stop but was removed by an idiot. I had the bits n pieces but could never figure out the wiring! THIS VIDEO WILL HELP GET IT UP AND RUNNING FINALLY!!!!!

If one opts to use a static phase converter, make sure you read/understand the instructions! I was able to get a used Ronk static converter at a really good price. One thing the paperwork emphasizes is that nothing except the motor itself gets connected to the created/generated leg. I had to trace out, and sometimes move, wiring on my controls and relays, in order to use the converter on my surface grinder. Another item is that the converter must be tuned to the machine, or you risk overheating and damaging your motor. If you can't get, follow, understand the instructions to your particular converter ... get help! Statics are not "plug and play." Especially on a machine that was previously used in a shop that had commercial 3 phase power.

Great explanation, my starter switch has failed on my Boxford lathe, so your explanation has helped me understand, which new switch to buy 👍

Thanks Keith.

well explained

Keith this was a great video. You explained everything very well. Do you have any videos on wiring up and changing voltages on a transformer.

Wow - difficult thing to explain, always been a bit of a black box to me, but now I get it. Thank you!

There is one important aspect of using a starter that wasn’t mentioned: current. The motor needs LOTS of it, and contacts in the starter are huge so they can handle it. The coil that’s turned on and off by the remote switch is very low power, and the remote switch can have small, convenient contacts. It’s a very small power controlling a very large power. If you wanted to use a switch directly on the motor, it would have to be huge.

Good explanation! One comment regarding the "protector"... A 3 phase motor will burn up if it looses any ONE of the three phases. (The other 2 wires draw massive current) Hence, the motor-protector is intended to trip when a single phase is lost. (again...because the other 2 phases will draw excessive current)

Very well done. I teach this at a votech and I may use this in my class thank you

In the video at 5:27 when you are explaining how the motor starter works you said that normally the circuit is closed actually the circuit is normally open until the coil is energized. Great video though keep up the good work !

An interesting aside, for fractional or small HP motors, Shop Fox makes a paddle type on off switch that has a coil and contacts in it and functions like a magnetic starter but without the overload protection. Grizzly sells this switch in both a 120v and 240v version (110v-220v) but makes no reference to the relay. And like the magnetic starter, if the switch looses power, the contacts open and the motor will not automatically restart when the power is restored. And it is like $15.00 if I recall correctly.

Love that"I'm not electrician but I learned how to deal with"😊😊😊

For reference. This is called a "3-wire start/stop" and the type of circuit is called a latching circuit. Very well explained Keith!

Good morning Keith

Very nice, Keith, but typically 14:00 start is NO and stop is NC 😉 Which you stated correctly at 14:12 Folks should keep in mind pressing the stop button interrupts the circuit, just like the overload does. And, and, you can have multiple stop switches wired in series with that one stop switch. Multiple stop switches are handy on a large machine if the operator may step away from the main control area (hint 😉)

Another use for Motor Starter Type Switching is to protect Electronics. It shuts off the Ckt at the Hint of brown outs or Flickering Power, Like Auto reset Power line breakers and they Stay off till You deem it safe to turn them back on. I have made a few with just an Ice Cube Continuous Duty 10 Amp relay, Nc & No buttons. Then I plug a UPS into those if Needed.

Great instruction. I'm glad you got around to the safety stop button at the end. With that machine are you contemplating using a safety stop? I spent nearly fifty years in a production environment where the Safety Stops were mandatory and not mandatory. I know you are not in a production envoronment with many people around at once, however please take the safety stop into consideration. If you are going to station the operator at the start stop switch, then it becomes somewat safer, however if the operation requires moving around the machine, mulitple safety stop buttons could save someone (especially you) from serious consequences. Those Safety stops are cheap insurance against serious injury or worse. In addition there may be some liability issues when you host one of your many gettogethers'. Just a friendly note from an old Safety Manager.

You can add normally open auxiliary contact blocks to the Allen Bradley or the Square D motor starter as to do the same thing as the American Rotary starter, the only issue with those smaller starters is the longevity of them. As a electrician for 40 plus years, to me nothing beats the old school AB 505 motor starter like you had there, they are bulletproof and will last a lifetime, I have seen way too many of those newer starters fail in the last few years.

I wish this had existed a couple years ago when I was figuring this out the hard way. Thanks Keith!

Life saver

One of my mills has ancient DC motor controlled by a 1945 SquareD starter. It controls the startup inrush current via a dashpot and three resistor banks. It had been miss-wired and one of the internal straps was missing. If the schematic and care instructions weren't on the inside of the cover, I would have been out of luck. It works correctly now.

Dear Sir, Thank you very much for your time and you help me how to connect the motor. Can you explain how to connect booster switch to solar hot water heater system?

Sure would have been nice to see that square d switch hooked up also though, since that's the one I have, but great video...

Keith, I may have missed it, but in your explanation, I didn't hear you mention that the remote start/stop switch can be utilized with a "pilot" voltage, entirely different from the starter internal line voltage, and, in fact, that is most often the case. Regardless of the size of the starter (which is sized so that the contacts can handle the full line voltage), the holding coil can be replaced, allowing the use of a 120/3/60, external "pilot" circuit to energize. Why would you do that? Usually, it's to save money on wiring to the on/off switch, and the added additional safety of a lower voltage circuit. In my professional life as an industrial air compressor sales engineer, I sold literally hundreds of air compressors in the 5HP to 25HP range, and I'd estimate that 75% of them used 120v control voltage if the line voltage was anything other than 120/1/60.

Even the way Keith draws the electrical diagrams is vintage. We haven’t used those little half circle bridges where wires intersect for 40 years. Since then the wires just cross each other, and when they connect, there’s a dot where the wires are crossing, to designate that they’re connected. Sometimes that aux switch that’s normally off, is used for a brake.

Good morning from SE Louisiana 21 May 21.

Not included or necessarily relevant in Keith's case, but starting capacitors are also worthy of analyzing, but googling that will produce a number of good tutorials.

Don't forget kieth .coils have different voltage ratings .and contactors have different current ratings .👍👍

I never thought about these switches. Great video. Question: why don’t they use a simple on/off light switch?

So are these what helps to not overload your grid when starting a 3 phase motor? As 3 phase motors don't have condensers like split phase does to help start them,?

Usually L1 L2 L 3 has 130 volts going thru them coils usually only need 24 volts and push buttons so wouldn't hooking the switch to L1 be to much or the auxiliary contact

Did Keith ever utilise light indicators on his compressor switchboard to know when it's powered or in an error state?

Hiya Keith

Keith, you're a fuckin G my man!

I just wonder how many tradesmen were sacrificed before motor starters became the norm. Well explained Keith. Regards

I believe they also save or limit the need for heavy cable to a switch and preventing all three Lines having to go to an on/off switch. High voltage is more dangerous no question so this starter idea only uses one L vs. 3. I think its mostly about electricity safety and user safety plus the magnetic starter fully engages the circuit efficiently vs. a manual switch could engage the circuit slowly causing arcing and heat depending on the operator working the switch. These typically get invented due to hazard and safety concerns over the years.

Is it worth putting a Variable frequency drive on a synchronous or asynchronous motor? Should the VFD be only used with a servo type motor? Example lathe drive motor with no gears(VFD servo)

Can use the aux for lights! And or an coolant pump

Ok, I get it now. If we see the back of Keith's hand, the circuit is energized.

Keith, You don’t mention another function of a motor starter. It provides a no-Volt release so that if the supply fails it will turn off and so when the power is restored the machine will not start unexpectedly. In the UK start buttons are normally slightly recessed so they are difficult to press accidentally while stop buttons have a large mushroom head so are easy to hit quickly in an emergency. Is it not the same over there?

How new is the new mechanism? I have the new one on my 20yo Grizzly table saw.

Hello Keith, great vid., but having trouble w/Oliver 299D planer. It had a 400v. AB starter. I have rewired motors for 240 and bought a 509 B0D. As you know the planer has 2 motors an seperate switches for feed/cutter head. Would like to connect w/you thru VM website as I am also a member. TY

I think society in general has given us a warped sense of what is “normal.” Finally, a video that explains it. Nomal(ly) closed - you get the beep. Normal(ly) open - no beep. JK!! Also, the overload section protects the wiring as well as the motor. This video will really come in handy when I get to the motor controls on my 10ee. Thanks Keith!

Im getting lost on the black and blue wire could you explain it more

what model push button starter are you using Dayton 20c794?