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Forum Index : Electronics : Where to find large Toroid in USA?
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| tinyt Guru  Joined: 12/11/2017 Location: United StatesPosts: 438 |
Out of curiosity, I enquired tcmetal if they sell to private person and they do. But not the toroid core but the slit coil of any width (from 0.5" thru 36") which we can wind to the toroid OD and ID that we want. My enquiry is for 0.27mm thick M4 (C5). Coating generated by chemical and thermal processing plus inorganic filler. I have no idea what it means. But they have a minimum order per strip width size of 500 lbs at $1.50/lb. FOB. I don't know how much the shipping will be. I don't know how many toroids it will make, probably quite a few. A lot of money for me, just to make one or two medium power toroid. |
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LadyN Guru Joined: 26/01/2019 Location: United StatesPosts: 408 |
Thank you. Here are my thoughts: 1. I (we) would like to make these inverters 2. These inverters need transformers to work - those on this board who can guide us are comfortable using toroids 3. Those of us in the U.S. are having a real hard time locating scrapped toroids and we have tried 4. We have found an affordable source for the building materials for toroids but the min. qty order is a bit too much for one person Do we agree with these? Anything I missed? Questions: i. How good would power line transformers be for our inverter projects? My brother works in construction and he knows linemen; they told him that they have to replace these power line transformers regularly. so there is an ongoing supply of these. These are HUGE EI transformers. VERY VERY heavy too but they can be obtained at scrap prices and there’s a continuous supply ii. If these are not an option, we are back to toroids: in that case, I can have my brothers and dad make the cores and ship them to you. If all of us are interested, we can probably meet the needed min. qty order or even exceed it iii. However, I need to learn the detailed manufacturing process to turn those strips to cores. I watched a video earlier in this thread and it looks doable except the annealing process which could get very expensive if large amount of heat is needed as we have an electric oven and we pay 50c/kWh I could look into getting a propane oven if it helps move us forward but I would rather not do this unless propane expense would be vastly lower than electric. This way, I can order the min. order, make them and distribute to you all at cost. I would like to take this forward but I want to make sure I understand the whole scope and details of it so I can keep my word and deliver what I am promising. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
There would be enough there for three or possibly four sets of transformers. Its 500Lbs minimum order, but that order could very likely be made up of several equal parts shipped out to different people. Its probably mainly about setting up their slitting machine to the correct width and then running off 500 Lbs of material. Winding that into three or four coils instead of one should not be such a problem for them. Its probably worth asking. Natasha, Some years ago, I built up some identical inductors using ordinary low cost transformer E/I iron laminations, and grain oriented silicon E/I laminations of identical sizes to compare the inductance. I did not measure loss, just the inductance of the assembled and ungapped steel cores. The difference was around roughly thirty percent. That tells us only about permeability, or the inductive loading on the power source. Eddy current loss is the resistive part of the loading on the source which mainly involves the resistivity of the steel and lamination thickness. Your larger transformers may also use slightly thicker laminations which will be far more lossy. I have never worked with really large power distribution transformers, but they are never normally run unloaded, so idling power is never a design issue for them, but its critical for us. The main problem with using very low grade material will be the increase in idling power which might realistically be 50% or more higher. That can be a significant penalty, as the increased battery size to accommodate all that wastage, will not come cheap. Its a really tough call. If you can get hold (borrow?) of one of those monsters and do some tests its probably the only way to find out. Cheers, Tony. |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
LadyN I think these big transformers have flat wire in them but some of them may have regular wire Wire is very expensive so it would definitely be worth looking into be warned i am good parrot but Dumber than a box of rocks |
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| LadyN Guru Joined: 26/01/2019 Location: United StatesPosts: 408 |
Tony, thank you. Borrowing it won't work in this case since the city is involved. Ben, you are right! From memory I DO remember a weird type of wiring from when one of these caught fire and they took it out. Can we reuse that flat wire? Don't they look like food wrap al. sheets? It was many years ago I think the total weight of those power line transformers are ~200lb. I don't know how they are distributed between the core and windings. The city will not sell to me directly but the linesmen say they send it to a scrap company approx 90 miles north of us, so a 200 miles roundtrip. Last time I inquired, in December for scrap metal for heatsink, they said $1.25/lb. So, 200lb will cost $250. I don't know what the cost for these transformers will be but it might be higher because the windings are involved, or maybe they strip it It might be cheaper to pool together on this order, specially if they can ship to us individually. My brother was willing to fly to Ben to take them out for dinner, pickup some transformers so it might be possible he can fly to this place and manage the transportation to ensure we are getting what we need if that will help us. He's off duty unless we go to war with Iran in which case he might have to go to camp as early as next week to start redeployment. I am really praying that does not happen. We will plan this. I'll have dad call and ask. Will report back in a week, unless that’s too slow? He is at the hospital on base at the Camp for his scheduled shots this week. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Its looking like purchasing the metal strip and winding the two largest toroids ourselves may be surest and most most economical way forwards. Very off topic, but US military have been mobilizing for quite a few weeks now, but I very strongly suspect this may have more to do with the introduction of martial law, and not deployment overseas. Enough said. Cheers, Tony. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Really--if you have any actual information concerning this, it's certainly not "Enough said"--it's far too little. Otherwise it's slanderous conspiracy mongering. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Thank you very much indeed. Cheers, Tony. |
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| tinyt Guru Joined: 12/11/2017 Location: United StatesPosts: 438 |
Had more answers for my follow up inquiry at TC Metal: Freight charge to deliver to my place which is about 16 miles (25.7 km) is about $129. But I will need a forklift to lift it from the truck. They said alternatively, I can pick it up from their facility and they will load it with their forklift on my truck (I don't have one). I asked if they can make the 500 lbs into five 100 lbs so they can be manually lifted. They said they can make it into smaller coils 100 lbs each. |
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