Siemens motor overload relay teardown

[@TheFirstGhirn]

Please don't apologize for the time taken to disassemble the gizmos your working on. The sneaky little tricks employed by manufactures of such things is worth knowing for us that like to fix or autopsy such things, and your calm nature is comforting right up to the "get the hammer" point. Thank you for your efforts.

[@EShirako]

Even "Get the hammer" Is helpful...violentish, maybe, but still helpful to show me where actual professionals sometimes go "This thing is totally not worth opening politely...one moment please!" and then the hammer comes out. It's an excellent example for us all! :)

[@samakovamk]

Oh...i was waiting for the screwdriver in the finger scene....Ouch....blood, blood......"one moment please" ..off camera swearing.......lol

[@michaelcherry8952]

9:00 "You can skip forward if you want to see all the gubbins without all the hassle..." Not on your life! Watching you puzzle out how to disassemble components is the best part!

[@Sparks66]

I knew this statement was somewhere in the comments section 👍🏼👍🏼

[@EndlessDelusion]

I love taking apart broken industrial electronics when they pop after a breakdown. Not only do you get to see how it ticks, you get that reassurance that "yes, it was definitely that"

[@bigclivedotcom]

And sometimes a clue as to something else that may have caused it to fail.

[@zombieregime]

Part of the joy of your videos is hearing the commentary and watching you working the thing apart. If nothing else it give hints to our own disassemblies. Of course the little quips and brain droppings are always welcome, the bits of wisdom and thoughts of an old salt sparky, 100% gold every time. Never apologize for being you, Clive! [internet high fives]

[@fonkbadonk5370]

As a PLC guy that only does programming, these puppies were always "something our cabinet guy built in" and "a signal to feed the motor control block" to me. Cool to get an actual insight! Especially since we almost only have Siemens parts, so this is a familiar looking thingy.

[@dashcamandy2242]

Siemens commercial/industrial line is among the best-of-the-best. I've also never had a failure with their 12VDC relays (automotive applications). It's one of those times where you absolutely DO get what you pay for.

[@fonkbadonk5370]

@@dashcamandy2242 Absolutely! Also with their PLCs. In 20 years, I have yet to see a CPU fail in any fashion. I've seen maybe 4-5 IO modules acting up after 10+ years, and the odd PSU, but overall reliabilty is really good, and well worth the price if your 50k€+ of product per day plant depends on it.

[@michaelwebber4033]

When I was a baby electrician I went to a candy stretching machine at night that had a tripped overload. I reset the overload and it tripped instantly. So I tested everything and ended up disconnecting the motor. The motor ran fine. Turned out the gearbox had siezed. They definitely work

[@professorg8383]

99% of the time. overloads are mechanical in nature.

[@NFBartos]

@@professorg8383 tell me about it. The only motor related call out I ever had that wasn't a mechanical jam causing an overload to trip, was when a VSD completely shat the bed and needed replacing. I'd get a call at 2am saying the auger or pump is tripping again, I'd even ask them if the shit was jammed up, "no it's fine, must be an electrical issue." Drag myself out of bed and get to site, first thing I'd do is open the inspection hatch, or remove the outlet pipework, and have a look, sure enough, jammed to fuck. 🙄

[@techtastisch7569]

@@professorg8383 Pretty much the only electrical issue I encountered was a broken (phase) connection on the terminals of an conveyor motor. It only ran on two phases so it drew to much current

[@themadhippy6911]

Brings back memory's of one of my first jobs as an apprentice ,stripping down and cleaning loads of old contactors.Along with adjustable trip current they also had oil dashpots to adjust the tripping time , when the overload tripped it brought in a solenoid that pulled a metal plunger up through the oil that broke the coil circuit..

[@BTW...]

If it had oil dashpots it wasn't a TOL like this... it was a Thermal/Magnetic Overload.

[@dashcamandy2242]

1:49 - And for some reason I feel it should be said, the normally-open (NO) contacts on the overload protection could be used to operate an indicator lamp to notify the user when the overload has tripped. 3:30 - Never mind. 😆 7:07 - They are beginning to use FVD (variable-frequency drive) in HVAC systems in the US. The main problem being the VFD drive is typically housed in the RTU (rooftop unit) where it gets exposed to harsh sun PLUS reflected heat off the roof itself - plus the internal cooling fan pulls all sorts of dust, soot, and pollen into them. They fail in a rather spectacular manner, especially when those fat juicy capacitors have had quite enough of that thermal abuse, thank you very much! I personally don't mind watching the longer-disassembly videos. In today's world of instant gratification, I still prefer the "slow burn."

[@BTW...]

Sounds like you work on poorly designed equipment with insufficient IP ratings.

[@sparkyprojects]

At the bottom of the bimetalics is a double slider that trips the mechanism, if all 3 phases see the same current within range, all 3 strips may move a little But if you lose 1 phase, one of the 2 strips will move more than the other, which will trip the device even if the remaining phases are within tolerance, known as 'single phasing protection' also, if you are not isolating the whole panel (you could cause problems if you do) randomly pressing reset on all contactors could be an issue, the reset is also the stop function, it will disconnect the control circuit of a wiorking contactor. (press the reset while testing contnuity to see what i mean)

[@DavidGauthiersquidpride2014]

Yes , the style of overloads detects single phasing. However, they can be used in a single phase operation as long as you take the output of one leg and redirect it back into the overload on the third leg. That way you get even heating of all three elements thanks for the observation 😊

[@BTW...]

Sure about that? If one of the 3 phase is lost that associated heater will NOT move. The other 2 will move the same degree - "one" won't move more and initiate a trip condition. The "single phasing protection" derived from higher current draw on the 2 live supplies as a result of a phase loss, and is very very basic indeed. It only works on motors under load. You know these TOL can be used for single phase or 2 phase over-current protection? Just because it has 3 phase connections means they must be used for 3 phase supply. Lose 2 of the 3 phases and there is no such 'single phase protection' in a delta wound load. So, that term "single phase protection" is a misnomer - try phase loss protection instead. A substantial control panel will have 'phase loss' monitor devices, being the correct protection instrument for supply fault conditions. In such control panels NONE of the reset buttons is used as a 'stop' function. What you suggest is only found in basic stand alone DOL starters. Not all TOL modules open aux contacts when pressing that reset. Some even have a separate 'test' button and some have an 'auto reset' position on that manual reset button.

[@BTW...]

@@DavidGauthiersquidpride2014 Nope... you are wrong. These do not trip on differential between each pole. They only trip if one or more phase heaters exceeds the set point for mechanical tripping of the aux contacts. There is NO need to double or in fact triple "take the output of one leg and redirect it back into the overload on the third leg." There is NO need to run an Active and Neutral of a single phase motor supply through the TOL.

[@sparkyprojects]

@@BTW... I've taken several makes of overload apart, they all had the part i mentioned, if one phase is lost, that heater won't move, and because of the sliding mechanism, it biases the other 2 to trip quicker. even the old allen bradley's with dashpots had something similar You can put all the electronic protection you like in a circuit (yes we had phase monitors too), but they can fail more than a simple mechanical system

[@villehietala9677]

@@BTW... There is a difference in force that one vs three bi-metal strips generate for tripping. All the manuals i have seen for these have had jumper wires for 1-phase use. And the connection diagram (for the whole contactor+thermal relay set) has always been supply to L1 in -> L1 out jump wire to L2 out -> L2 in jump wire to L3 in -> L3 out to load. I probably have some orphaned smaller ones somewhere and could try to trip them. There should be noticeable difference in tripping times, but it takes several alternating tests to filter out overall warming and ageing of the thing. Bench power supply should give stable test current and it should not make any difference versus mains ac. Though as I am an electrician, it would be easy for me to safely run something like space heater through one. If I could find matching devices to make the trip time to be >minute, so that the trip times would be close to real life situations with broken phase etc.

[@Steve_W471]

Taking the time to rip things apart and explain them from an educated and experienced mind is what makes your channel great. It's brilliant.

[@gavin9038]

These were (still are) used in Schlumberger petrol pump dispensers from the early-90's. The ones I've worked on have the variable current setting on the side as a pendulum style lever, set quite low in the factory and then nudged all the way to maximum (10A or thereabouts) by field technicians over the years when worn out motors start to pull more current. Never had to replace one in the 15 years I've been in the job.

[@SeanBZA]

Only time I replaced one that was faulty was when the motor went short to ground on one phase, and burnt that thermal sense element out, so it was replaced with the motor. motor went short because the phase imbalance on the unit failed, and the contactor dropped a phase because of a bad contact assembly. motor ran, but with more noise, till it finally went out and tripped the breakers. 8kW motor, 138kg cast iron case. New aluminium case one was a lot lighter.

[@kewakl8891]

Great timing. Just this week I disassembled two allen-bradley overloads -- cat 529 and cat 815 - to show new-hires how they work.

[@Dan-vq4pz]

This is wild Clive, this is only the second overload I've ever encountered that only switches the control terminals without interrupting the current going through it. All of the WEG, AB, ABB and Schneider overloads I've seen break the power section and the control section

[@paulmccoy2908]

No, you’re describing what’s called a “manual motor starter”.

[@BTW...]

@@paulmccoy2908 It's a bit of a worry how unqualifed workers get their hands on equipment like this.

[@BTW...]

Nope, you are only working with small scale stuff then... hopefully.

[@chrisstorm7704]

Reminiscent of the Sprecher-Schuh model I took apart some time back. That one had an inductive trip and heated trip mechanisms. The heaters were used in such a way that all 3 strips pushed on a lever arm and a certain level of load imbalance would cause a trip even if the overload current had not been reached. Mechanical devices like this absolutely amaze me.

[@technobabble_]

Hey we have a lot of these at work, it's nice to finally see how they work and how the machine's control software know they've popped. Also i wasn't expecting them to stay on and just switch off the contactor control voltage. Very helpful, thank you!

[@davefuelling7955]

As a machine technician, I also deal with overloads quite often. The control circuits are generally, but not always, run through a transformer off the mains. There are several different designs of overloads but they all pretty much work the same way. They shut down the control voltage to whatever they are protecting and there is then a start switch in line with the overload to re-energize the circuit.

[@BTW...]

The same TOL is found in stand alone DOL starters too. In such applications the supply voltage is used for contactor coils... perhaps 120V, 240V or 415V. In a DOL starter the STOP button will act on that 'Reset' button on the TOL. Yeah... as noted in the video, these act to interrupt control supply to the contactor they attach to. Sometimes TOL are not attached to a contactor, being stand alone devices. A STOP button will be wired in series with the TOL aux. contacts (NC circuit) in a multi-motor control cabinet. This will not 'Reset' a TOL. A START button will not reset a TOL.

[@ssgeek4515]

Blows my mind that someone somewhere drew this mechanism down on paper when first thought of.... brilliant sir

[@Ampman]

I remember the bad old days when the heaters were separate parts you would install in the contactor , one for each phase and 2 screws for each one

[@SeanBZA]

Yes have dealt with them, but is is exclusively a US equipment thing, the rest of the planet dropped it decades ago, but the USA still uses it in places. You can stll buy them as replacement parts for old machinery, where the owners are loath to change out the contactor for a modern more reliable one.

[@jkobain]

I won't speak for us all; yet, the very process of tearing things apart is quite interesting on its own. So please don't cut it out, those who's in a rush can always skip forward or just get back to watching trillions of YT Sharts, or whatever important thing they usually do.

[@billdoodson4232]

Nice to see you taking something apart thats not total cr4p. Used to use a lot of Siemens contactors and control gear, always good solid reliable gear.

[@309electronics5]

Siemens is also german Which for me also adds extra trust knowing its from a european country who has good engineered/designed neat products

[@apuwdm2]

This channel is such a friendly way of learning knowledge and technology. Thanks for sharing and for your efforts. Absolutely invaluable source for the genre of people that have learned engineering by taking things apart (and hopefully put them together). I remember a time in my dim and distant youth, when my parents bought their first quartz alarm clock. Previous to this, the alarm clocks were the wind-up, spring and escapement type. As expected, their young and curious son sat through the night, while everyone slept, taking the new clock apart to have a look and then luckily put it together to a working order, before the house awoke in the morning. Absolutely love your channel.

[@jazbell7]

I love watching you take apart modern industrial control things. I spent 25+ years in industrial control, but things back then (70s-80s) were much more crude and klunky.

[@mkepler5861]

I love watch you take stuff to bits, it saves me the time of doing it myself, and your commentary is spot on!!!

[@phils4634]

My first ever "paying" job whilst waiting to go to University - building these (and the associated contactors) in Arrow Hart, Roborough Ind. Est., Plymouth. Interesting (though a bit repetitive), and a valuable insight into "industrial" spec. electrical systems! Overtime was guaranteed, and the pay was excellent!

[@KeritechElectronics]

Nice teardown. Basically a classic bimetallic thermal switch designed as a contactpr extension - they've been around for decades.

[@amorphuc]

So cool Big Clive. Thank you for sharing. My dad was a calibration engineer for Stewart Warner in Chicago up until the early to mid 70s. He would have loved this video as well.

[@markmurphy3578]

We had thermal relays in telecommunications for various reasons and they were very good for both timing and protection. I’d forgotten all about them until now!

[@SeanBZA]

Additional function for these is protection against phase loss, which is done by having that trip bar in 2 pieces, with trip being caused by either the 3 bending over too mach against a spring, or if you loose a phase you have one that does not move over with current, making that the trip point is now a lot lower, and tripping fast. Normally you have an option for manual reset, or automatic reset, where the contacts will change state on trip, then, after the shunts have cooled down, engage again. Normally selected with either a pin, or a slot on the actuator bar that keeps it in reset always. The units are not expensive, around the same price as the contactor, though of course you have a few different ones per model of contactor, with ranges with quite an overlap, so that you can choose a trip current matching your motor. Often used with a push button station, where the green button presses on the actual contactor coil to close it, then one of the aux contacts holds the contactor on, while the stop button resets the overload, ensuring that each operation of the stop will reset the overload, and drop out the contactor, or that the motor will not start and run unless you press stop first, to reset it, telling you it tripped for overload or phase loss, not for power failure.

[@echothehusky]

I was working on a very old table sander recently, the overload was a similar design, just much more rugged and not enclosed. The contactor contacts were also open and were huge for the 2A motor load, they looked like they could easily handle 100A.

[@Leahi84]

The teardown is one of my favorite parts, so no skipping for me!

[@SirHackaL0t.]

I like watching the teardown parts. It makes me feel better when I struggle to take things apart. :)

[@robertburrows6612]

That to me back a few years as an apprentice electrician in a factory, making and repairing control panels. Those were the days doing bespoke work from wiring diagram, you were just giving the electrical specs and of you went to make a control panel, because you couldn't wait for the manufacture to send a replacement as a machine down was costing thousands in lost production. Most sparks these days won't know what your talking about if you said star start, delta running

[@Sparks66]

A lot don’t understand CAP start CAP run either 🤔

[@SeanBZA]

Or that you need to set the star delta transition time on larger motors, because you need ot get it right, or have a rather massive spike on that transition. Or the installer who wired the motor wrong. It started in delta, and after 5 seconds switched to star. No wonder the machine had a tendency to walk itself off of it's floor mounting bolts. fixed that the day I saw it do that, and when i replaced control circuit I dropped the star delta timer completely, and instead used a 8kVA soft starter instead, and a new contactor and overload unit with the new motor. Adjusted to ramp up as slow as possible, and set to the profile for a large fan. 30s to get to full speed made for a gentler start. This was a 5 ton blender for powder.

[@bigclivedotcom]

They do work it out when they manage to poke both contactors in simultaneously. As for the start and run rated caps. It's usually just one cap now. Noting that modern motor capacitors do fail faster than the older ones.

[@SeanBZA]

@@bigclivedotcom Yes have noticed that, to the point I would not even bother testing them after 2 years of use, and simply replace with new, or add in a hard start unit across the capacitor, as that at least would allow it to run even with a capacitor down in value.

[@davebayliss2278]

Im with Daniel.....taking things apart is always an adventure and a certain amount of experience helps the process...

[@michaelcomiskey1168]

Big Clive helped me cope during Lockdown. Thanks Big Man. ❤

[@memejeff]

Very nice contactor. At first I was thinking that it would use a ptc element but quickly realized that, that wouldnt work due to the ceramics high resistance. Always amazes me how factory workers can assemble this stuff at scale given the complexity.

[@BTW...]

These are assembled by high speed machines, no hands applied. Gone are those days, unless the gear is over-priced due to labour costs.

[@stevecoinitin7521]

Used to fit these most times to contactors when I assembled industrial heater control panels. Can't remember the brand, but they had a white round dial for Amps selection. The cross head screws always needed checking when wiring up as you could too easily put the wire behind both small plates, instead of between, which had caused localised fires a few times! We had little room to see and closer inspection was a must! And those screws could fail making you think they were done up tight, so always the tug test! The units are good and reliable when used correctly, but was not keen on that screw system.

[@toma.cnc1]

It is not just overload protection, it will trigger on loss of a phase, always and protect the motor from burning to a crisp. Where i live, the phase loss is much more important that overload, hence i use those a lot and have several in a box collecting😃 dust waiting for their turn to go work!

[@toma.cnc1]

I did not put the smiley there, it was at the end when i clicked send!!! KZbin, wth???

[@bigclivedotcom]

You can also get phase failure modules that will break the whole control circuit if a phase goes down or the machine is connected with wrong phase rotation.

[@steveosshenanigans]

Clive why you using your old screw driver ?

[@tonywebb9909]

So funny Clive, I had my head in a boiler room panel for three hours today looking at six of these units. Two had been bypassed and one had failed. Only there to illuminate a red light on the front of the panel lid which everyone just ignores. Digital systems can send you an email which you also just ignore!

[@AiOinc1]

These are used in many of the machines I service - Dishwashers, mixer grinders, etc. Some of them are directly built into the contractors and are inseparable. Usually use the NC contacts.

[@gcewing]

I think I dismantled a more primitive version of one of these many years ago. It had the three heating elements, red and green buttons for turning it on and off, and a big knob on the side for adjustment. It was clearly some kind of overcurrent detection device, but I didn't know exactly what it was designed for at the time. I'm pretty sure this video has solved an old mystery for me! BTW, mine was a lot easier to take apart. :-)

[@connclissmann6514]

Siemens gear seems solidly built

[@SeanBZA]

Well, had a lot of Siemens stuff that stopped working eventually, after 40 odd years, well past the warranted lifetime. Rated only for a million cycles, but went well past the 20 million mark, though there were some switches that made it past the 10 million cycle mark they were warranted for, though to claim would be hard, as the switches physically wore parts out, or the contacts went intermittent. Guessed they were over 20 million cycles, based on the previous owner of the machine running it for 20 years on 3 shifts, 7 days a week, at full speed. Still had a whole slew of the original INA and FAG bearings in it, all still fine once greased, and the only thing that did fail was an original VARIMOT drive, which disintegrated the clutch spring. Obsolete, so went to the Fenner catalog, and got a 2 belt pulley and Fenner Lok hub, and machined the middle out, to fit the VARIMOT belt, which I can still buy off the shelf. Then put a VFD unit on the original motor, a fan for forced cooling, and it ran well. Forced air cooling to compensate for running at 30Hz,

[@badmeatbrowniesthoughts1327]

Best part of my day? When Clive uploads. It's that simple 😌

[@kenjohnson6338]

Rebuilding a grinding machine now... had no relay or reg inside... just bought them second hand... Will fit in a couple of days..! Is a learning curve for me..lol...!

[@fredbrown7954]

Excellent explanation of overload protection 👍

[@masteryoda394]

It's a good idea to put the Siemens model number in the description. It will help your video get more attention from individuals looking for part information. Keep in mind the 24V version and the 120V version have different model number.

[@Ralesk]

What a lovely little device!

[@luizmarxsenjr]

Bimetallic strips are a good example that ones of the most awesome technical solutions are the simple, they can be used on some automatic devices such thermostats and thermal cutoffs, another applications for bimetallic strips are in car dashboards, as analog meters such fuel, water temperature and oil pressure...

[@paulmccoy2908]

There’s also an electronic version that uses magnetic sensors instead of the heated trip mechanism. The latest ones are powered by the internal current transformers and don’t require separate power.

[@guyh3403]

A gazillion parts, yet still reliable. Nice!

[@bobweiss8682]

There are at least 2 other variations on these devices. The older one uses heater elements to melt tiny pots of a low-melting metal alloy like Wood's Metal, and when the alloy melts, it allows an embedded cogwheel to rotate under spring tension, tripping the mechanism. And there are more modern electronic types which use current sensors, a comparator circuit, and a time delay circuit to trip a latching solenoid.

[@unmanaged]

Would love to see a deeper dive into these indusrtial control elcronics.... I know a bit about electronics but not industiral controls and this video had be learning alot .... Cheers.... :)

[@jeroenontour]

It reminds me of repair i was send to. The column drill was not working and they needed the drill continuously. In the meanwhile the mechanics created a wooden board with a screwdriver attached to it. By pressing the contactor with this construction they keeped using the drill. It was my easyest repair i ever had. Just press the reset button and it worked again.

[@Sommyie]

I needed, srsly, every minute of this.

[@tundramanq]

This protects the motor from loss of one or two phases and then motor stalls and the still powered phases frying. High voltage power line lightning strikes or trees on a line are good at tripping just 1 or 2 of the phases.

[@siegfriedhollrigl8421]

I would NEVER skip the best parts of the video. :-)

[@AlpineTheHusky]

In German this would be called a Thermorelais (Thermal Relay). As always german describes the device in the name :b. Siemens also makes those relays with 5 connections to the contactor, fully automating the shutdown. I have also seen some weird ones that actually do break connection but only on a single phase as if you got a motor protection relay before it (often its redundant but sometimes its good for extra protection) it automatically trips that one aswell.

[@Tims_Projects]

I used to watch those videos where someone tries to work out a puzzle. But all I do now is get out the popcorn, sit back an watch Big Clive take something apart 😄

[@dutchmetalmaniac]

great tutorial, thank you. now i KNOW how it works instead of ASSUMING it.

[@310765]

Thanks you very much Clive. 😁👍🏼

[@Thermoelectric7]

I recommend grabbing a Sprecher + Schuh CEP7 (-1 maybe, dunno) electronic overload to tear down next. Been a while since I've pulled one apart but they do some magic, same form factor but I think they're CT based, they're parasitic too and don't require an auxiliary power supply. Magic little devices.

[@rose-ey6ct]

You mention loss of a phase tripping the unit through overcurrent, but all of these devices also monitor that all 3 phases are drawing the same current, and if 1 bimetallic fails to move in parallel with the other 2, it also trips. Nowadays I try to avoid these things in favour of units which also isolate the motor directly in the event of a "trip". For example, a Telemechanique "GV2".

[@SueBobChicVid]

I'm in the US with predominantly 120v ac control circuits. I've always found it curious that the overload contact is one of the very few devices wired to break the neutral to the contactor coil. All other control contacts will be on the "hot" side, but the convention for these was to break the neutral. Of course, there are exceptions, but they are rare in my 30+ years of field service.

[@frednitney5831]

I'm in the USA too, however the "norm" I've noticed is 24V AC or DC (if PLCs are involved). Indeed, I was "shocked" (emotional, not physically ;-) when I discovered a piece of equipment that used a 120VAC e-stop loop. A safety device that is "potentially" (pun) a safety hazard: who'd have thunk it! Note that I work on a small assortment of expensive equipment in a particular industry, so my experience may be atypical.

[@SeanBZA]

Well, most overloads are wired for either a control transformer use, or across phases, so no real difference in there, you have 2 sides of a circuit. But most of them I find are wired so the coil is the lowest element, with the start switch and sustain contact in parallel, then the overload, then the relay coil. With the Siemens units there the coil has a handy pass through terminal, as then you can have a single wire jumper, or for factory units a stamped link bar, that connects coil to common, then from there you wire in the NC side, and have a jumper wire to the 14 terminal on the relay, and power applied to 13, with your neutral to A2, with start button and stop button being remote and fed with a 3 wire connection. I used 4 plus ground cable, because I also fed back a neutral, so as to have a power pilot light there, and ground for safety.

[@Zlodej5]

I am in UK, having been a sparky in few EU countries and I dont find its rarity curious. As a rule you always want to cut live to prevent non-powered devices from being live. So it is natural that most of the equipment does control live side unless it has a good reason to do otherwise.

[@steveosshenanigans]

I find it unusual that the Yanks will switch the neutral in most A/c systems that i have come across

[@Zlodej5]

@@steveosshenanigansMeutral only or do you mean both? when you have inductive load that might continue inducing power after supply was cut there is sometimes handy to disconnect more then just live. Cant think of this happening on a petty Aircon. But disconnecting only neutral in actual end device is usualy sign of bad workmanship.(the device in a video is disconnecting switching device on neutral not the end device).

[@Trebuchet48]

When I was a very junior engineer 50 years ago, we just used a "slo-blo" fuse!

[@Kevin_Hones]

I enjoyed the slow pace - most enjoyable. But there again I initially read the subject as “Motor Overlord Relay” so probably safest to ignore me 😀

[@daansteeman5227]

I'm in industrial automation. So I see these things quite often. We dont realy use them anymore in favor of a motorprotectionswitch. (MBS in dutch, PKZ in german) its basically the same thing but with the mains contacts. But these do have the advantage of not being that expencive because of lack of mains contacts. I think the small once like this are around 30-40 euros (even from siemens). The larger once are more expencive ofcourse. But in industrial terms its not that bad. I orderd an 80A version from Sneider a couple of months ago. I think it was 80 euro or something.

[@lordbyrom100]

It’s a great make good to work with ,I’m of the day we had dash pots with oil in that worked on electromagnetic force which increases with current .As you will know a motor on start up can take up to 6 times the current .I also worked on face plate starters …great fun ( no electronics then ….😊😊😊)

[@HiddenWindshield]

15:44 "Push all the red buttons." -- Big Clive 2023

[@bdot02]

What current was that rated for? Those are tiny little wires for powering the equipment. Must be for something nice and small.

[@tonyweavers4292]

I have a vague recollection of installing one of these and releasing some unexpected magic smoke.😂

[@curtishoffmann6956]

Comment added to increase engagement. Warp thrusters engaged, Captain.

[@curtishoffmann6956]

Sorry, I did that wrong. Engagement thrusters warped, Captain!

[@d.t.4523]

Thank you. Keep working, good luck.

[@CyberlightFG]

Could you tell the hvac guys, that this is not a motor starter, please?

[@bigclivedotcom]

In some instances it can function as a motor starter.

[@curtw8827]

I seem to recall the U S devices are also rated Class 10 or Class 20 that had different time to trip characteristics to use on large inertia loads to delay tripping on start up.

[@MsLancer99]

The motor overload relay remains me of our axle counters of the Heritage Railway. The axle counter is mounted just inside the rail and can just tell the signal man the train has just pass that point or it can be used tell the signal man how long the the train is and the speed or all of that and turn a signal to red and if on a signal track lock the points and signal on red at the other end until the train passes the axle counter at the loop and so on. It's just a box with two switches wired up to a power cabinet that intern wired to the signal box under the floor but it works

[@gregorythomas333]

Haven't seen inside one of these really nice ones before...pretty neat...thank you for sharing :)

[@markvanheuveln4670]

We used a variation of this device in our field supplys for shovels.

[@pontusmellgren1153]

Love this kind of videos. whuld like to se a teardown of Downlight with drivers. to know how and why they go bad

[@bigclivedotcom]

I've featured a few. It's usually either fried LEDs or a failed capacitor in the driver.

[@phonotical]

Another video release, so soon? Mr Ambassador, you spoil us 🤣

[@quandiy5164]

I have opened up ones that are rated at higher amps. There are no heater coils. The bimetallic strips are the heaters.

[@NeilPBrooks]

Fascinating! Thanks!

[@strenter]

I only knew them with an additional blue knob beside the reset button that could pushed in and turned to stay down, being able to auto-reset the device that way. This sure only is a workaround in very remote locations that need to operate, or maybe the backup pump.

[@chickenwing111]

In the US the coil voltage is typically 120 VAC and the overload device opens the neutral side of the coil to drop the contactor out. I'm not sure why it is done that way. Maybe for ease of wiring.

[@johndododoe1411]

I'm guessing that front piece with the NO contact is available with other functions according to control system needs, especially when that control system is a bunch of other relays and push buttons in a standard box with a diagram in a folder somewhere . I've seen diagrams that unfolded to well over a meter to describe just one box . controlling a machine smaller than a shipping container .

[@justme5384]

I had a standalone overload relay trip on a motor. Measured voltage on the contactor it operated and at first everything seemed fine. Turns out the contactor had welded two of the three contacts and when the demand for that motor went off the motor only got two phases that had welded together and that then tripped the overload relay

[@superrascal664]

the last video - numbered 2200 - Ordinary product with iconic component - has been removed ?

[@gearloose703]

Should do a test how quick they trip because in case of small motors like this, fuse won't trip. I guess the goal is to trip before the winding is damaged.

[@villehietala9677]

Search for a comment by sparkyprojects that has now 40 upvotes. I replied my measurements there that I automated to run for last night.

[@soupisgoodfood42]

"just push all the red buttons..." I will take this advice and apply everywhere in my daily life ;)

[@gordonlawrence1448]

Time to use the vice of knowledge and the pliers of enquiry.

[@uksuperrascal]

Hi Clive - the last video numbered 2200 - Ordinary product with iconic component - has been removed ?

[@bigclivedotcom]

Still there. kzbin.info/www/bejne/p4mZi3-Cq6ephLc

[@frednitney5831]

Very informative and useful (at least for me). Thanks!

[@literallycanadian]

Its honestly always a bit weird to me that devices labeled as a motor contactor don't come by default with these overloads. You always need them. A typical breaker is designed for a much shorter trip time that can be expereinced from a motor startup. Now this one is a very very basic unit. Slightly fancier bimetalic overloads are actually configurable with different trip curves, trip currents. Even fancier units have completely replaced the heaters with electronic monitoring elements that are even more configurable. as few new cost, we just got quoted a bunch of old bimetalic eaton ones and they are about $50 CAD a piece. Now the cool thing is, there often is actually 2 bimetalic strips, one which is heated by the heater to trip, and one which is heated only by ambient air to serve as a ambient compensation if the unit it is in is quite warm.

[@Iowa599]

You know it's well made when BC has trouble breaking it!

[@sootikins]

Interesting. I've installed hundreds of those things but never opened one up. One thing: in your diagram at 1:20 there's no short circuit protection. Not sure how you guys do it in the UK but here we typically put fuses or a breaker (the "mag trip") ahead of the contactor. Maybe you just wanted to keep the diagram simple? Also, customarily we break the coil's neutral with the thermal OL and the hot side with the controls. Not sure why, it's just how it's always been done here.

[@bigclivedotcom]

It was for simplification. There would be suitable fuses or a breaker.

[@rickseiden1]

Hey, Clive, do you have any plans to celebrate 1,000,000 subscribers?

[@bigclivedotcom]

None at all - due to being a bit disorganised. I'll probably do an impromptu stream.

[@rickseiden1]

@@bigclivedotcom It's a huge accomplishment. Congratulations, if a bit early.

[@the_tux]

A well known saying: „Does it have to work or shall it be something made by Siemens?“.

[@Lokomowal]

SIEMENS = "Selten ist etwas mit Elektrik noch schlechter"

[@Erik_Swiger]

@ 7:50 "What's the next bit we should take apart?"If there's education, entertainment, and ordinary bitter, I don't care, I'm all yours for the afternoon.

[@carlwedekind3868]

I used to work at the distribution center of a major retailer. There was about 12 miles of conveyors in a 1.5 million square foot building. The whole system could be monitored on the computer. One night the monitor started calling out multiple motor overload trips throughout the building. The system ran on 480V three phase. Turns out that one of the phases from the utility had risen to 510V. Those overload relays probably prevented a lot of damage.

[@EMAngel2718]

I wonder if it would be beneficial to have a way to detect different amounts of current between the coils

[@BTW...]

It does. If this is used in a 3 phase application (and that could be used in a 1 phase situation) any of the phase 'coils' (heaters) will trip the aux. contacts. A fault condition could be both an imbalance due to a loss of one phase fault (causing excess current on the healthy 2 phases) or overcurrent condition on all 3 due to excess loading on the motor.

[@BlackWolf42-]

So, is that considered to be what I've heard here in the US called a "starter"?

[@UhOhUmm]

Contactor is still called a contactor in the US. Motor starters are most often electronic these days, using solid state hardware.

[@mxslick50]

A motor starter contains most or all of the following: A disconnect switch, line fuses/breaker, control transformer, contactor, and overload relay. A very basic minimalist starter has a contactor and overload relay.

[@RelakS__]

"Overlord Relay" 🤨What? Read it again! "Overload Relay" OK, it has much more sense now 😁