I inspect the build quality and sine wave output of a Samlex inverter. I also check the output of a lower cost Motomaster inverter. Thanks for your help! Early access to VJOs / ave
Dude did you take down your video on ethanol in fuel? It's one of your best videos in my opinion! I've opened many peoples eyes with it. I had some more enlightening to do today but when I went look for your master piece I cant find er. WTF man.
As a power electronics engineer: Look at the cheapness of the board, its a single sided and looks like FR1 or FR2. To minimise current loop area it should be double sided. No one uses these modified sine wave inverters for professional applications, just get a pure sine wave one and lose a bit of your power density and efficiency (you will save it in power losses in your motor!). There are some large motor drives that use a modified sine wave but they are designed for specific motors and applications. It's OK to parallel up MOSFETs as they have a negative temperature coefficient resistance so are unlikely to cascade fail. Using different types in parallel is never a good idea though as the worse ones will not conduct and just add to the switching time. Diodes have a positive temperature coefficient and shouldn't be parallelled unless they are on the same heatsink, and cut from the same die preferably. I can send you a DIY high quality sine wave inverter to test if you want to see what a good one looks like. PS. To get useful readings from your fft you have to exactly one cycle displayed on the screen (that's 20mS total for 50hz, good luck with 60hz). Then look only at the amplitude at each harmonic and ignore the rest.
@@pleaseelaborate3163I'm guessing you mean converter topology. I've tried using both high frequency (20khz) and low frequency (50hz) transformers to step up the voltage and low frequency is the way to go unless you need to make it lightweight. Output filter topology is whatever passives happened to be lying on the floor during testing
So what are the basics of a DIY pure sine inverter? H-bridge and back to front transformer? Do you need to regulate input wrt output or is that automagically adjusted by the load's power demand?
I have a mechanical engineering degree with a 3.7 average. When I watch your videos I feel so dumb, but yet so eager to learn more about material science! I'm so happy that I found your channel, it is awesome! Thank You! :) Much love from Norway!
Your videos got this C-Student through undergraduate Electrical Engineering without losing my mind. Learned the hard way "a bunch of angry pixies" is not an acceptable answer on EE exams. Congrats on 1M!
Sadly we've reached the point where many "name brand" items aren't really better than the cheaper alternatives. They're more expensive without putting that cost into quality.
I believe that is the end goal of capitalism and publicly traded companies. Constant profit numbers until you run out of demand and plateau. Then the only solution is to increase margins.
@@jawms Capitalism has no end goal like what you wrote. It is the free market of production and purchasing. The market currently promotes cheaply produced crap at various extremes of mark up. Unfortunately, it would take a lot of us consumers demanding higher quality at the same price by not buying the junk at any price point to get the companies to up their game. Execs and shareholders will take less profits over no profits.
Buddy, I feal I should be paying you for the refresher. I went to tech school over forty years ago for electronics and you are a brilliant son of a gun. The basics in school helped me all my life as an electrician. I love your video's . You are also very funny. Thank you !
5 лет назад
I have a new conspiracy theory. Just let it eat your mind. AvE has a long term marketing contract with the green mat manufacturer.
Every video I watch of AvE reminds me of the stuff I've done in the past. I once used a 150W amp with a signal generator to create a power supply for a 4" 400Hz muffin fan that ran at 20k rippums. It had a very pure sine wave output.
Uncle Bumblefuck, please consider a vid or short series on home solar power from a technical perspective; the basics of the equipment and procedures that make it work, not burn the house down, and not bleed juice back into the power company's lines when they think they're de-energized.
To reduce cornea searing from sparks on my 3KW pure sine inverter wired up a 5w 110v bulb and used it to limit the current before initial connection. Bonus is you can also use it to discharge the unit if-un you want to open her up and dilly with the innards
Facepalm ... the Intellectual na'palm err um, Smoke ... as a result of the skid marks left by high density pixies after dey been triggered, thus requiring safe space, and soft-ware ... way too excit'd & offended wit the hard--ware.
maybe, but not every one is measured in "Giga Ohms" like you so they do not dare! ;P but i really thought the same, that little extra board is probably the only reason... or they cherry picked all the +/-% at there best tolerances!
The internals of the $600 one remind me a lot of an amplifier, usually with car amps roughly half the PCB is an inverter to bring it up to 50 or something volts before going into the amplifier section. Switching class D amps are super efficient, 90%+, and output that pure sine wave after going through filter coils. Makes you think why these don't use similar technology. Realistically all this'd need to become a pure sine wave inverter is a coil and faster switching. When JBL first showed off their 6000w monster at CES they used it to power a reciprocating saw, and I'd guarantee it'd be better at running an air compressor than any non-industrial inverter. There are a few 35kW amps out which output into 1 ohm, which means 170 volts at 170 amps. 60Hz sine wave and you're powering a house no problem.
Long hard day, but in the end nothing like drawing a nice hot bath, pouring me and my cats a bottle of wine, and settling in with my favorite RU-vidr, but I'll watch this video before I switch to that channel.
If I was a VCR company I would definitely hire you to man the phones in the time setting technical assistance department. Your eloquent dialogue would be a huge asset for confused customers.
Power supplies are commodity items unfortunately. Difference between brands will mainly be QC. Reason is that there is minimal 'new' design work involved vs existing products. The bulk of engineering hours spent is for cost down or assembly efficiencies.
@@legendario13 It is a proven phenomenon that the public routinely assumes a greater price equates to a greater value. Something manufacturers and marketing departments exploit on a daily basis.
This is a switch mode inverter. It steps up battery voltage switched with some of the mosfets through the 4 small transformers at high frequency several thousand hertz rectified stored in the two capacitors located in the center. Chopped up by using the mosfets. Thus providing the modified signwave. The output stage is likely a h-bridge topology with complementary components. Really for the price I would much rather have the lower cost unit.
13:25 I just wanted to point out that you had set the meter in the AC-Range while testing for remaining DC-Voltage in a capacitor. Such a mistake can be very dangerous. IGBTs also do not always fail open. If you overload them or overvoltage them they will fail short like every other power semiconductor. You can get an open failure because of bondwire liftoff. This can be caused by high temperature cycles/ripples, that weaken the bond.
Sad truth is that the vast majority of inverters on the market are really shitty. I have had good luck with Xantrex ProWatt inverters, and I have heard that Magnum Energy inverters are top notch. But they are expensive.
“Dandysocks”! Brilliant. A decade ago, I met some Canucks, and they complained about Dubya getting his dad’s old job. Shoe’s on the other foot now, eh?
You had me checking my headphones to make sure the audio wasn't coming out of my desktop at work, thanks for clearing up that the audio on the video was different
Modified sine wave: becasue modified square wave just doesn't have that same ring to it. (And be cause it won't sell that well to the unwitting consumer)
Modified sine/square wave would be a lot more useful if it indicated how it was modified. A 5 or 7 level stepped square wave would be much nicer than the 3-level one here. It depends on what you are powering. For a nightlight, it doesn't matter. For sensitive electronics I'd much prefer a better system.
6alecapristrudel I can not work out whether the ‘ring’ in your comment was serendipitous or whether it was a perfectly crafted joke. So just in case, I doff my cap to you!
The Caps usually also fail when the MOSFETS blow. Voltage sag on a single battery is more significant because as the voltage sags , the amps increase to provide enough watts to invert. Thick wires and many parallel batteries greatly improves the operation of cheap and expensive inverters. If your battery terminals or the battery cable get warm/hot, then you need more parallel batteries and heavier cable. 48 volt batteries, 8 X 6 volt or 4 x 12 volt and a 48 volt low frequency inverter will deliver more power at lower amps and lose less of your angry pixies to heat.
"guys wanted to see a worse load on there so this guys been eating asparagus all week... nastiest load I could find" AvE you have me in tears my dude....
I was watching the battery voltage...it kept dipping below 11.5v when it overloaded...I think you need to give the battery a real good charge before making comparisons. All the inverter was doing was shutting down on low batt volts.
It often happens with power tools that the inverter shuts off. It's because the tool needs a lot of power just to get going. It also helps if you just give it a spin. That's essentially what you were doing by keeping the trigger squeezed. I've got an inverter in my campervan which powers my compressor fridge. It almost always starts beeping when the fridge compressor starts to chooch. But it beeps only once, because once it chooches, it needs less power just to keep it going. Things that don't require much startup power like a water boiler or something are way easier for the inverter
Do you think it would be possible to place something in between the battery and the inverter to keep the voltage steady during a current spike like that? Like a capacitor or something? Would be a fun experiment and improvement on the system. Though it might drain the battery.
Yes, as someone else suggested, get one of those BS power saving devices off ebay, it's just a large capacitor and it will be able to supply things such as motors that sudden inrush of current it needs to start, although as always the better solution is to buy a bigger inverter that can put out higher peaks of power.
New subscriber here. Not trying to be "that guy", but I genuinely look forward to watching every video you have made. I have always had an interest in how things work. You make these intresting, thank you!
AvE, if it helps, your chain analogy for parallel circuits sounds like a trampoline to me - all the springs holding the load/weight together. If a spring pops, each has more weight, etc.
Heck the stuff I worked on as an engineer, the mosfets typically failed as a open.. They do initially short out and then blow apart from the current. All that's left is the leads and heat sink tab, hence an open circuit.. :D It was real easy to find the one that failed.
I definitely appreciate how you tear these things down and examine them. In this particular case, I bought a 10K watt modified chinesieum inverter 5 or 6 years ago. It was only 350 USD. I wanted to take it apart before I put my solar system into action, but I didn't. I have to say, it's the best one I've ever purchased. I ran a solo clean line to my breaker box on a 30 amp circuit, and have used it many, many times to run my house. On a conservative level, of course. Lights, fridge, dish washer, fish tanks. I imagine that it'll monica lewinsky one of these days, but there are 4 replaceable fuses. Right across the front. Money shot.
I tried to help a guy get his conventional single stage high efficiency gas furnace to run off his modified sine wave inverter/solar system. The first time we tried a call for heat, the furnace control board started shrieking like a stuck pig. Never heard one do that before. I thought the board was finished but, once back on the grid, the furnace worked normally. The guy figured out to use a pure sine wave inverter, cost him $5K back several years ago, but the furnace worked OK off it.
I'm 43 when I was 17 I met this local car stereo shop Kevin "Hitman"(ran out of his garage, his empire of dirt) we would install and compare brand name components to the cheaper, all the time and effort we put into these systems, and there was not much difference, much like you just showed. Some difference but that little bit of difference wasnt worth the extra money. We took most of the local sound shows. With our 2 or 3 thousand dollar systems. Watching the losers drive away with there 5 or 6,000 even 10,000 dollar systems. We once put 36 six inch woofers in a VW golf. That car hit. They were pyramid pro series. Cheap.
I've always blew away high end systems with pyramid in the mid to late 90s and I still have those amps and subs and they still work lovely they've been in 9 different cars so far and I'm positive they'll outlast the next ones
lol BS i did it too back then and a pyramid or pyle etc wasnt killing anyone rockford and memphis or ppi list goes on mtx too you be lucky if that pyramid lasted a month
So is a pure sine wave inverter basically a 50/60hz function generator strapped to an audio amplifier? Something I have heard of being done in a pinch to convert between 60hz and 50hz or to step down 120V-240V to 110V-120V with a pro audio amplifier (1800W @ 8 ohms / 3600W @ 4 ohms is theoretically 120V AC)
Essentially that is one way to do it. as I recollect, and I am no expert, a hartley oscillator amongst others produce a nice sin wave which may be amplified through A, B, or AB type amplifiers to produce a nice high power output at the desired voltage.
@@Jimmeh_B that is not correct! There are two common inverter topologies ...high frequency and low frequency...the latter have heavy Fe core transformers, and both can be pure sine wave. The latter are much better at surge and short term overload conditions. Someone who is educated in this field can identify which topology is employed from the spec sheet.
Well, yes, but only if it is a class-D amplifier. Also they do other stuff like try to detect if there is a load, and going into a sleep state if not (this saves battery power). The problem with class A or B or AB is that it wastes too much power. We usually want our inverters to be efficient because we are usually powering them from batteries.
I'm actually so f*ckin glad your doing stuff with inverters. Needing funkshoning pixie utilitarians, when you're a rookie is a pain. Bumblefuck skool of sinusoidal crocks for the freakin win... Thanks buddy, love your work!!
I find that soldering connections like the one that had failed are a bit tricky in that your instinct is to poor the heat and pile the solder on and you get a good connection. Problem is the metal components are cast into plastic, so you have to minimize the amount of heat applied. I melted the crap out of a switch like that a couple months back, then realized that you're supposed to use crimp lugs on it. This outlet connection is obviously not a crimp lug connection, but it is one of the (relatively) few that are done by hand and the person failed to apply enough heat and solder. I suspect that when you repaired it if you applied too much heat you could easily damage the outlet. Suspect being the key word.
We install and replace a shit load of inverters at work, and it's always the MOSFETs that blow out of them always! One thing I will say about samlex is they seem to last the longest. the main reason for that is not build quality, it's because they have a lot of built in protection for instance if you're using too small of a conductor or if you have a loose connection on the back of the unit it will not work. We seem that a bit here with the low battery voltage issue you were having. I have pile of these things kicking around I may open one up myself and see if I can fix it. there definitely not a cheap but I guess your paying for the " intelligent safety features" kinda like that shitty saw you took apart sometime ago it was built like shit but had a thermal shutdown so they charged an arm and a leg for it.
You should see if you can get a peek of a Cotek inverter (bloody expensive). They have models that claim to be pure sine and others that are modified sine. I picked up a big 2000w one for spare/repairs - internals looked high end compared to what you have there (silastic on the caps, epoxy/conformal coating over everything). Alas, I was out of my depth in trying to repair it, even local eletronics repair shop couldn't get it to chooch - having to waterjet the epoxy/conformal coating off didn't help matters. EDIT: this is similar to mine: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sNWMXOtAzAA.html
i have a bunch of cheap ass inverters $80 2000 watt ones, and as long as not constantly overloading or anything terribly abusive they last forever. i have a couple that still working after a solid 10 + years. the thing is, you cant expect a good sinewave out of even the best portable inverters.. if you need a proper sinewave probably best off not using an portable inverter. i heard from some friends that deal with electrical engineering you can take the edge off of those modified sine waves by adding some of those cheap chinese "power saver" devices that are basically 1 or 2 huge super caps in a metal box ..plug that into the outlet on inverter then plug in device to it.. good for taking the edge off of huge spikes like start up of grinder maybe, and filtering some noise out. not going to filter out smaller noise under smaller loads but it can help..
is there a hack to get smaller amounts of harmonic distortion out of a cheap pure sine inverter though? i've got a cheap pure sine inverter going, have not had any issues yet, but it has some distortion in the high kHz region going on...
first imma say, this is mostly justa field of curiosity for me, i am by no means the go to person on this, im just relaying what i been told: that's the only issue i still have which hasn't posed any problems for me either, is low/no load situations still noisier and have their digital edge, probably a way using same logic just smaller caps and inductors on output to filter it will help. also depending on the frequency we talking about here, that be its own field of engineer. because high frequency energy seems to have their own physics.
Taking the edge means dealing with high frequency components. The capacitance of theae "power savers" is a few uF which at higher frequencies will act as a dead short in the worat case and as a heavy load in the best case. What you need is a choke in serie with the outlet or better a common mode choke
The square wave we see with this device is literally the definition of a modified sine wave. Some modified sine wave inverters will have an additional step in the middle, but it's not required.
like i have all ways say . running a MD inverter is like running a car on bad gas.. it well run but for how long . if the job calls for a SW inverter then pay the higher cost for the unit then for the cost of what it kills latter
I had a 5KW inverter modified sine wave, that came out of Sellafield back in the mid 90's. that had 60 mosfets a side and one day most of the blew with many of them exploding. I had to buy so many replacements that I still have half a tube of IRF 540's left.
I want my Patreon money back. RU-vid was down for 30 minutes. I'm going through AvE withdrawal and its someones fault. Do you know how many times I hit refresh???
Both of those are cheap inverters. The online UPS's tend to have fairly nice inverters designed for 5+ years 24/7 use. Things are real cheap too if you get an older one with dead batteries, like an Eaton 9120 2 or 3KVA, or an Eaton 9130.
Thats not strictly true the inverter side of a ups is always in standby not continuous use but yes you can get some nice ones because they tend to be used on sensitive equipment
Not with an online, or double conversion UPS. The inverter runs the load 24/7/365, input power or not. They are of course much nicer than the cheapie line interactive units that are only made for intermittent use, but they also tend to have loud fans, notable standby losses, and high initial cost.
Jon Doe is correct Liljasere, in proper Line interactive units, the inverter is always powered, as its kept in sync with the Mains input, and in APC Units is also run in reverse to charge the batteries, so as soon as input drops, the load is switched to the inverter and the unit loads up off the batteries. You are thinking of the very cheap "Standby" units which only start and run the inverter once power loss or out of spec is detected. Line interactive is much faster to take over. Then you have Online double conversion, where AC is rectified and regulated into DC to charge the battery bus and power the inverter which is always powering the load at all times, unless the unit is in bypass, either due to a fault, or in Eco Mode. As soon as the power drops (when not in bypass) all that happens is the AC to DC rectification and battery charging stops, and the batteries seamlessly supply the inverter, which maintains a seamless zero transfer power output. Not quite as efficient as Line interactive, but wont cause issues with highly sensitive equipment either like a Line interactive sometimes does to fussy loads (If you have an APC line interactive, set sensitivity to high, unit reacts much faster and load drops are less likely, seen this personally). APC makes some really really nice units with their Smart-UPS Series. knurlgnar24 did a whole series of videos on them. I personally use APC Smart UPS XL (Online Line Interactive) and Smart UPS RT (Online Double Conversion), and they both output exceptionally clean power often cleaner than wall power, even the 15+ year old 700XL is very clean and still working.
Looking at the transformers I think that they are both switch mode. They first step up the 12 V to the peak voltage, about 170 V, then have a bridge on the output to switch polarity. This would account for the mismatched MOSFETS as some are used in the step up DC/DC converter and the others on the output bridge. As you say thay are both rubbish. With the more expensive one being slightly better (ignoring the soldering fault) though the electrolytic capacitors look pretty dodgy.
If you want to avoid that sparks on switching stuff on you have to use a solid state relais which can switch on the zero crossing. It's also much better on stuff you run via the inverter, since you avoid steep voltage drops.
Another great video. Just to let you know but IGBT's can also fail shorted. I was a senior field engineer for Emerson Network Power for 30 years, servicing and commissioning Inverters as big as 1600 KVA and the majority of IGBT's failed shorted.You sometimes had open ones it depends on the failure mode(over voltage =open/over current=shorted).Those were much better than a shorted ones. Due to the fact that IGBT's have a non passive end of life characteristic(kaboom!) most open ones were because they blew themselves open. Better to have an open one than a shorted one when you try to bring the DC buss back up.
@@mrdumbfellow927 Nope. I do have a pair of real leather pants and boots though. I grew up on a working ranch and did own a pair of chaps when I was 8yrs old.
Thanks man. Makes me think about taking pens apart. Teaching is as good as learning. Everytime! I aspire to work with metal. Signed your average timber frame guy.
I’ll bet you didn’t unplug the grinder before you took the disk off I have seen first(very bloody) hand what that does to a man when the trigger gets knocked
Yep, take the batteries out of cordless ones as well. A zip-cut disk goes through leather gloves in about half a rotation, and most of a finger in the next rotation!
my buddy did not have any gloves on, it was a grinding disk but the hand got wedged between the disk and the guard. that ment i had to free his hand from it
AvE what do you think of that Fluke 87V. I am looking at adding that meter to my troubleshooting arsenal. Does it provide a good bang for the bucks it cost? It is sad yet I found a great inverter at harbor freight for my service van.
If you want the best video on YT that explains these inverters, Google "Inverters, How do they work ?" and get the one made by "learn Engineering" channel.
Reminds me of Barevids Amplifier repair. Great vids and would love to see a co-lab with BigClive..... p.s. I don't have a sodding iron either! I have a soldering station. (pedant)
