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Forum Index : Other Stuff : Diesel engine muffler?
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| Ironmaiden Regular Member  Joined: 09/07/2019 Location: United StatesPosts: 53 |
Tony, I had forgotten about the Scott T transformer. The idea sounds good in theory. I bet finding a set of transformers to wire in Scott T would be a real bugger these days though. Really big E-I Xformers are getting scarce in the 240/120v rating. When I do find them they are crazy $$$ priced. Robert Edited 2019-08-19 09:41 by Ironmaiden |
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| Davo99 Guru  Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Both transformers are almost always wound on a single E/I core, but in a rather special way. A normal E/I transformer has all the windings on the centre limb. A Scott transfomer uses the two thinner outer limbs as quite independent transformers, with nothing on the fatter centre limb. Scott transformers are a bit of an oddity, and pretty useless for any other purpose, and would be difficult to sell. You might get lucky and find one that you can buy for scrap value if you hunt around and are patient. Cheers, Tony. |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Davo, I think with these motors as generators it's mostly trial and error. There is a lot of variance in induction motor manufacturing and no two machines perform the same. Edison's split phase gives good voltage balancing, but can be a hindrance too when it comes to single phase from a three phase generator. We can get either 2/3 capacity across two phases or 1/3 capacity across any of the phases to neutral. Have you seen the IGC/ELC design here? http://microhydropower.net/mhp_group/portegijs/humbird/humb_main.html Looks like it's going to be a pita to get the PCB made since the author didn't include Gerber files. Looks like a lot of time in KiCad is needed. Some of the first Imag installations used both a IGC and ELC. They didn't switch resistors. Instead they switched a binary capacitor bank to control voltage and frequency. I am interested in trying out under/over voltage relays to switch in and out the capacitors for regulation. This fellow was on a similar track, but his diesel tractor wasn't up to the task of powering an Imag. https://www.youtube.com/watch?v=N3luyI2RIOc He needed a belt drive governor like a Pierce or Hoof governor for the tractor engine to work effectively as a generator engine. Robert Edited 2019-08-19 11:28 by Ironmaiden |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Re things we can get in the states, We have an abundance of just about anything for the right price available all day long. However, There are some things we can't get thanks to our stupid EPA. We can't get the Lister clones or the Changfa type diesel engines over here. The AK-47 or Swiss Army knife of diesel engines for generators are simply unobtainable here sadly. They do come up used for crazy $$$ once in a blue moon. But you can't get parts for them either. I guess Canada is a little bit better off on that front. I wish someone would rain in the pollution of the political fruitcakes that run our country. They make more smog than all the little diesel engines combined. Stuff it already you babbling morons! Robert |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
The big problem here is that unless the drive rpm is held constant, and the load is held constant, the voltage is going to swing around pretty wildly. I have my doubts that any mechanical drive source can be given speed regulation good enough. Thinking about all this, I would take a quite different approach, and I have absolutely no idea if this idea would work or be practical. But we have two disturbing influences on out machine, drive rpm, and load current which will probably both be changing simultaneously fairly quickly and in unpredictable ways. There is only one parameter we can control, the tuning capacitance. So what if we very carefully bench test our machine over a suitably wide range of rpm and varying loads from 0% to 100% and create a map of the required tuning capacitance required to produce a constant (or almost constant) output voltage. This could be a simple lookup table in read only memory. For every possible rpm and load combination, there will be an optimum tuning capacitance value stored in the lookup table. This feed forward correction has the advantage of very fast response to changes without having to actually measure the output voltage. I am sure that a microcontroller could actually be given a self learning algorithm to very slowly over time make fine adjustments. But it would probably need to be programmed manually to get it working initially. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
I agree totally and why I said in a previous response that your goal of setting up for 240V was flawed thinking as was trying to calculate capacitance. I have never calculated it but the numbers your calculations were coming up with were so far away I knew they were wrong even if I didn't know what was right. I still think you are too high at 50 Uf in any config but if it works for your particular circumstances then it is right beyond doubt. Same as what I get re phase to neutral. we also get 1/3rd capacity phase to phase. I don't remember ever trying tying 2 phases together although if I did I forgot what happened. In theory should give 380V which is used here in some applications. Hmm, I don't know how that would work out. I think it would be erratic at best and the outputs would be useless for most practical purposes except really dumb resistive loads like heating. The swings are fast and even if capacitance was switched in early when the voltage only sagged 10V, it tends to be a crashing effect and as the field is collapsing, I don't think capacitance addition will stabilise it very well. My gut feeling is the field will fall, the extra capacitance will kick in, the field / voltage will continue to drop very low then it may recover and the voltage will sweep up rapidly, may over shoot some what as the load influences the engine driving the IMAG and the voltage and frequency swings would be a Disaster. Trying to power things like a fridge, TV or Micro off a supply like that would be a total joke. Add in the complication of something like a fridge. Kicks in and pulls 5x it's running draw for a second or 2. Relays kick in and then out and in and..... I can see things taking 20 seconds to smooth out no matter how fast the switching just through the reactive inertia of the spinning masses and having all these loads kicking in and out. Of course the Governors on most engines are not that great and I can see them just making the whole thing a disaster. What you really want is a 100HP motor running at a fixed speed. The load would cause minimal fluctuations and in the end I think would be a whole lot better than the stability a small motor with a governor would produce. With Tonys suggestion, I think the mapping would look like an engine management computer with 10,000 mapping points to get it to work right. I understand this is an experiment/ learning curve but at some point I think one needs to say Yeah, it can work, but the trouble and expense in MAKING it work is not worth it and I'd be be better to just be happy with a generator as boring and basic as it is. Again I think you are expecting too much out of this. Yeah, to drive your water heater or run some Floodlights as I once did for a party for a bit of fun, no problem. Wanting to run the house with a fridge switching in and out and a Kettle, Microwave, whatever, yeah, COULD work but well before you get to the end of the day you are better off going the boring normal generator route because it works and that's why it's used. I also think that starting off with just a 4 KW motor increases the difficulty straight off. IF you are dead serious about this and have that bee in your Bonnet that won't go away, then I'd say before you go setting up control systems and mucking round for this little 2 Kw Viable machine, Go find yourself something more worthwhile to put your time in. There have to be loads of these motors around, I have seen plenty of them here in scrap yards every time I go to one and I doubt there are 50% of them that are bad. A cheap Multimeter will soon tell you anyway and if you pay a few bucks above scrap value, you'll own the thing. The 12Kw Motor I got was a scrap rescue and Nothing wrong with it other than it had done it's prescribed service life and was changed out as part of routine Maintenance. Service life in industrial applications as this one was ( Driving a huge blower fan on a Chiller) the idea is to change them out BEFORE they fail, IE, are still working perfectly rather than cause non prescribed down time. Bearings are still quiet in the thing and I'll guarantee I'll be scrapped and gone before it is. There is probably less trouble setting up relays/ controllers for larger motors than there is small ones and you will get a far better and more useful product in return for your efforts. If the motor you have is not ideal, look for one that is and save the frustration there. Yes, he replied to a comment I made on that vid over 3 years ago explaining that. The reply he gave as to the capacitance switching I had forgotten about but he also found exactly what I thought would happen. That is a 10 KW motor as well so maybe the larger motors are not going to provide the greater stability I thought. Then again, I know from experience the Juggling act a little 5 KW motor can be. I had a 1.8 for a while but soon gave up on that. Also look at that prime mover. that has massive reactive power and would be far superior to a small engine. I was going to say rather than just looking at capacitance, looking for the Biggest Muther of an engine with the heaviest flywheels you could find or add onto would also most likely be a big help. I have driven Imags with a little China Horizontal engine which had a good size flywheel for it's size and I have Driven it with a CS Lister which has over 100Kg flywheel weight. The problems were similar but for reactive power, like anything else you cannot beat great big heavy flywheels. Looking at the complication this tact would need to work, I would go back and Look at what Tony said early on, Battery charging. Even a couple of small deep Cycles are going to give you the one critical thing you are Chasing, Stability. Use the imag to charge batterys or provide a feed to them and run an inverter. The inverter will give you good, stable power and the ability to have the fridge Kicking in and out and use any combination of appliance up to it's limit. There is the big problem solved. Now all you have to do is work out a rectification/charging system for the batteries which is going to be a relative Piece of cake. Best part with batteries and inverters is you don't need the engine running all the time. As this is a backup system you can also throw some panels at it and power it that way. Again I understand you want to make this work and learn but when I realise something is just not practical and too much hard work for the result, I kinda loose interest there. :0) |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1206 |
I've got a 16/1 Listeroid and I just buried some 3" hyd pipe and let the exhaust out about 10 metres away from my shed, the noise is close to silent and the music of the tappets is the only noise. The big laugh comes when I turn on my 3hp aircon and listen to the 5Kw genhead squeal like a stuck pig while the Listeriod doesn't even feel the current inrush. Cheers Bryan |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Listers are easy to keep quiet. When I first got mine I hacked some 4" Pipe onto a piece that fitted the screw thread on the lister (1.5"?) and stuffed in some stainless pot scrubbers ( the coarse kind) and drilled a tek screw in one side to catch them when they tried to blow out. the 4" pipe was about 3 ft long. Maybe 10" was full of the scrubbers. As bogan as all get out but I was amazed how quiet that made that thing even under load. An interesting experiment is to spin the thing up on the decompressor with an electric motor. When you stop most of the noise of the thing breathing in and out the inlet you can hear how quiet the mechanicals are... and you'll have reduced a lot of the intake noise as well. I got a car muffler off a Subaru and used that as the exhaust and it was basically silent. Intake made far more noise followed by the clack of the injector firing and the sound of the piston changing direction. Car mufflers are good because the gas flow from a 1.5L Lister doing 600 rpm is so much less than a 2L car doing 4000 plus the pulsing gives a bleed down effect as the muffler is likley to be more than the capacity of the expanded gas so it fills then bleeds down rather than being under constant pressure. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Yes, and it could work like an engine management computer. You may not require as many mapping points as you expect. Its possible to interpolate between mapping points, and that can simplify things a whole lot. If things behave fairly linearly it may only require two mapping points, one at each end of the whole range. Set those manually, than at any point in between the software works out a precise required proportion. Its only where you have gross non linearities that multiple fairly close mapping points are required, and you can still interpolate between those. We first bench test the machine, and decide how much output voltage variation is tolerable, and how many mapping points are required on both the speed axis, and on the load axis to stay within that tolerable range. Although all this may be possible in theory, its a lot of trouble to go to and hardly seems worthwhile when you can just buy a commercial alternator and fit a voltage regulator to it, and get excellent performance. Cheers, Tony. |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Tony, I am afraid designing a computer control setup would be over my head. I have seen some documents on Imag's that suggest the idea is sound though as far as varying the capacitors. I have something like 4 folders full of research PDF files I have found on the web. I am still 4 years on trying to decipher the data into something that makes sense. The equations I had put up on here are very incorrect because I misread the damn book. The delta connection one is the farthest out. The correct answer I got is 36uf. I would like to go back and delete some of it. The backshed won't let me though. The star connection for the caps always requires x3 as much capacitance as that of a delta connection. My first encounter with the induction generator concept was with Grieg's website. https://www.qsl.net/ns8o/Induction_Generator.html I was only a teenager when I found that site. I knew nothing about any of these subjects and was just starting out in learning about DIY generators and wind turbines, etc. I first figured out how to connect my machine thanks to Fozzer'S Forum which is sadly gone with the passing of the owner. It was an engine website like the smokstak to which I belong. I have drawn alot of my inspiration from these two sources on youtube. The one is such a poor quality video though. But the video confirmed the connection talked about on Fozzer's forum. https://www.youtube.com/watch?v=_ZnncSbzuqg https://www.youtube.com/watch?v=RKi9Trqcg3Y 50uf seems to work quite well on both my 2hp and 5hp motor conversions. The rule of thumb I was taught went something like, 500 watts per motor hp for output wattage. 10uf per motor hp for capacitors. Maybe it has to do with the way American motors are wound? I really don't know. I don't know how big the motor is you have Davo99? Maybe try a set of 50uf caps and see what happens? I have a set of batteries and a 5HP engine driving a 94 amp alternator. The problem is though inverters are not the most reliable things. I have had a couple of them self destruct during emergency situations. I don't have any faith in inverters. I have also noticed that for every 1 hour of run time on batteries, it takes the same amount of burning fuel to recharge those batteries. Efficiency is crap when you think about it. Robert Edited 2019-08-20 12:04 by Ironmaiden |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Well, that third video illustrates the problem quite well. At around 0:34 we get to see that is an 11Kw machine, its no featherweight. At 1:44 he runs it up under no load to about 230v At 2:17 he connects a lamp load, maybe 100 watts? And the voltage falls to 170v. Cheers, Tony. |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Tony, I translated what they were saying in the video as it's hard to follow. The problem is a lack of driving power. The little green motor is not up to the task of driving an 11kw generator. I have done the same thing using my 3 phase motors as generators driven from my 1/2hp repulsion start induction motor built 100 years ago. No load I can get close to 115v. With a simple 100 watt light bulb my voltage goes to 80 volts. I just don't have enough driving power either using an electric motor as engine. I would also call into question the VFD and the transformer he is running the whole thing from. The VFD is probably undersized for the motor acting as an engine. I think they would have been better off with a large engine for power. A 10HP diesel would have been far better than that little green motor acting as an engine. The electric motor doesn't have a governor to respond to load. I am of the opinion that such a MG setup needs to have an electric motor close in size to the generator, or be of a wound rotor brushed machine. A DC brushed motor might be even better. Brushed motors develop more torque. Robert Edited 2019-08-20 14:38 by Ironmaiden |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
But its not driving an 11Kw load. All its driving is a single piddling little lamp, and at only 170v to only probably about 54% of its rated wattage. Sorry, but I cannot get very excited about what I see happening there. As with the earlier video, about the guy with the tractor proudly trying to power up an unloaded electric drill. I cannot get too ecstatic about that particular demonstration either. Edited 2019-08-20 16:43 by Warpspeed Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Hmmm, I don't think so. The size of the motor is relatively inconsequential. Once it was spinning the difference in drag between a 5Kw and an 11 KW motor would be Negligible. Pretty much down to the drag of the bearings and the fan. I'ts the load that really determines the driving power required and 100W load should make no difference to a motor of any decent size. It's the effect on the magnetic field inside the motor that counts. The " top" bit of power is very Finicky. If you put on a 500W load and then another 100W load the voltage drop of the 100W load would be minimal. If you put that 100W load on it's own, it would be far greater. This is part of the inherent problem of an Imag. My little motor I have played with is 5KW. I tried 40Uf and 50 UF found it was too much. The motor was producing far to much power for the frequency and bring the speed up to get frequency caused massive Voltage overshoot. It also made it way Touchy on the speed control. Powered up quick and easy but was touchy to load and speed. 20Uf is a far happier place for the motor I have. I use that as the base for a C2C setup though so 20 and 40. I did try the other way, same amount and size of caps but didn't suit my purposes as well. With 40 as the base cap, was not at all hard to get 600V even with 400V rated caps. Like I said, I knew your Numbers of 100-160UF or whatever were miles out just from experience. I still think 36 Uf may be on the high side but you have to test Your motor under your conditions. I know this much for a certainty, there is no absolute across the board capacitance for a motor of a given specification. It's a matter of trial and error to get as close as you can to the right Voltage/ frequency balance if that is what you are aiming for. And im my experience, what is right today won't be so great tomorrow on the same Imag, motor and load. These things are REALLY Finicky. Another thing I found was the imbalanced loading thing seemed to be a Misnomer. I loaded my Motor up as hard as I could and ran it for some time. Not only did it not over heat, it barely got warm. Makes sense when you tink about it. The motor both on the set of windings and in total are well below what the motor was rated for as a motor when it would be dissipating far more power. I would have no concerns about an imbalanced load at all across the windings. The thermal mass, the cooling fins and the fan were all designed to remove the heat from a far higher power input. What sort of loading and testing have you done with your setup so far and what have you found? |
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| Ironmaiden Regular Member Joined: 09/07/2019 Location: United StatesPosts: 53 |
Mate, I haven't done any serious load testing thus far. I have been experimenting with the different connection schemes and have found that with my 50uf X3 cap bank, that I cannot get the generator to excite when the caps are connected star with the windings in star. I think I need even more uf. The equation suggest 112uf for star connected capacitors. I don't have anymore caps at the moment to get up to that value. We have more connection options thanks to having the Edison 3 wire system. Whether that is a good thing or not I haven't decided? Marathon Electric makes Imag sets for grid tie operation. The wiring schemes in their document are what I am experimenting with at this time. https://www.marathongenerators.com/generators/docs/manuals/SB317.pdf I haven't played with delta as I would need to modify the windings. I hate to hack a motor that is worth even used $250 to $300 US. The most stable operation I have found seems to be the windings connected low star (9 lead motor) and the capacitors connected delta. I can get 125 volts phase to neutral and phase to phase 240 volts very easily. I have found that as you state, different loads have different affects on the output voltage in ways that I didn't expect. I am thinking about using 25uf caps though as the motor starts generating too early, which means I have way too much capacitance connected in delta. I think my 4KW generator would be happy with a constant 1500 watt load on it. At that wattage the generator would be producing optimal output performance. A load test of a similar 5hp (4kw) Imag by Possum Living, https://www.youtube.com/watch?v=Q1GOr-S3BIs Robert Edited 2019-08-21 00:54 by Ironmaiden |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
I think we've been conditioned to accept small engines make lots of noise. I was a volunteer with the local rural fire brigade, on the back of the fire trucks are one or two petrol or diesel water pumps. These things are loud, way to loud. You have to shout to be heard over them, and one time a small fire got out of hand because the guy's on the hose couldn't hear the land owner yelling at them to look in a different direction. I've raised the issue at a meeting or two, why are these pumps so loud? But nothing comes of it. The fire trucks engine is many times more powerful, its running, and its quiet compared to the little water pumps. These fire trucks should be fitted with electric pumps, or proper mufflers ( both inlet and exhaust ) should be fitted to the existing pumps. Its a pet hate. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Well that's the first thing I'd be doing. If you want 1500W out of it you need to be doing your testing with at least 1000W on the thing. You may find that you work on getting one setup right then find it's no good at the load you want. These things are very different loaded and unloaded. Have you tired increasing the Revs? On my motor I used to have to give the engine a big rev or 3 and then you could hear the field start to saturate and the thing come up to power by the high pitched whine. Was easy to tell as with a multimeter. Speeding up the IMAG helps to energise it and if that does not work try flashing it with a 12V battery. You do realise the application they are applying them to is not as stand alone generators or used with caps but rather to back feed and correct power factor in industrial applications where they get charged more for their electricity of the don't keep the power factor under control? These are wired straight to the mains with no caps or form of excitation other than the grid power. This is a main function of the big motor I'm working on and the connection is just as one would have the thing wired as a motor. I think my 4KW generator would be happy with a constant 1500 watt load on it. At that wattage the generator would be producing optimal output performance. I agree but again I would be trying to do your testing with a load as the unloaded behaviour will be miles different. No use coming up with a setup and spending a lot of time on it only to find it's not workable when you actually come to use it. Edited 2019-08-21 11:26 by Davo99 |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Electric I think would be prohibitively expensive. The alternators, the motors, wiring and a pump to drive would all be real big bucks and no question MANY times more expensive than a common petrol pump. The Big appliances I believe have a PTO for the main pump which would probably be far more practical. Given the way things are looked into with all these emergency service Vehicles, I'd say there is a good reason why they use the pumps they do. Mufflers on most small engines aren't bad at all because they have to comply to noise regs. Small car Mufflers could be used however with some flexible tubing. Intake on petrols usually isn't a source of great if any noise either. Where a lot of noise comes from is simply the mechanical Racket. Thats hard to suppress on an air cooled motor and there aren't a lot of petrols in the 5-8HP range that are water Cooled. Water cooling would also add another failure point in this application so I can see why they wouldn't go down that route. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Its interesting though, that modern motorcycles seem to be fairly quiet from the mechanical clatter point of view, and the factory fitted mufflers on most road bikes are pretty quiet now that there are quite restrictive noise laws. So it is possible. But the small stationary air cooled engines by comparison, seem to be pretty crude and cheaply built. I have recently been having fantasies about water cooling my air cooled Wisconsin. Its a single cylinder side valve engine, and very basic. I could surround the cast iron finned barrel with a water jacket easily enough, and fabricate my own cylinder head, as its only virtually a flat plate with a combustion chamber hollow, and a threaded spark pug hole in it. I could weld up something fairly easily to completely replace the existing aluminium head. If its a failure, I can always put back the original head. When water cooled, the whole engine can then be placed in a sound proof box with a small external radiator. That should then cool by convective water flow, and a standard electric radiator fan. Its a bit of stuffing around, but its an interesting idea, and I can put something together at almost zero cost Cheers, Tony. |
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