"Wow that's not gonna work"... seems like a pretty useless transformer??.funny thing is I've seen people wrap speaker wire on them😲huh,wonder how long until it melted🤔.
Ok.i was perhaps a bit confused over those 4? Coppers.i didn't remember what I had before I cut the sides flush.i didn't perceive them as actual remains of windings.im gonna have to find another one to see what wires come off it.lol.thanku!😃
These are run into saturation to squeeze more power from them in the oven, the output of the magnetron is 600W and they are around 65 percent efficient so they are pulling 1kW plus from this tiny transformer, those are magnetic shunts and are there to allow leakage flux and therefore limit the output current you need to add turns to the primary or run a lower input voltage , the current is going into reactive power and heating the core, you could also run a series inductor (ballast), also a parallel PFC cap with help with idle current
MOTs are usually rated by their output current, I believe, but I think only half of mine actually have a rating on the transformer itself. The microwave's rating is the magnetron's output power. As someone else said, remove the magnetic shunts. I believe they reduce the flux in order to prevent core saturation which you won't need to worry about. But MOTs are ultimately just very inefficient transformers. They use silicon steel laminates where should be insulatated from each other, but the magnetic fields in them are so strong that they weld the laminates together in 2 places so they don't push the whole thing apart. This results in edfy currents that draw extra power and heat up the core. If you want less power draw at idle while using that core, you'll need to increase the reactance of the primary by adding more turns. Alternatively, you could run it at a higher frequency, but that's probably impractical in your situation.
Your calculations about volts per turn might be off a bit. Make sure you test the input voltage right on the primary. I wouldn't be surprised if you're quite a bit below 120Vac on the primary, *especially* under a load.
The microwave(plate) it's self "should be rated by its input power"if It wasn't a person would never know," is my/this receptacle sized for the load".im gonna look into this though.🙂
Ok thanku so much🙂.i have knocked them out now.i also added turns on primary as well.tomarrow I'm gonna retest.thanku for your comment and for watching🙂.
I was just about to say that as they where there and add another strand to the secondary winding for the 18v also i would have some insulation between the layered wraps use like tracing paper, I have made many of these for same reason but i was going for 14.8DC, when you finished your wraps dip into a lacquer or some sort of light resin, do not add to the primary as its not needed and if you added turns to the primary you will get less voltage on your secondary anyway. "to fill you gaps well you could add more strands to your secondary in parallel try to get them as even as possible like they are a multi-stranded cable". That 4 rows of copper you pulled out is another winding i forget its exact use but feed back. The other thing before you do any resin or lacquer make sure you blown out the transformer as much as you can as there might be some filings in the primary and if there is any enamel off of that copper on the primary it could short it, but yes microwave transformers have high eddy currents due to the fact they are welded laminated core the only solution with that to get the best results is more work where you grind out the welds and take the E and I lamination apart and lacquer them and re-assemble and clamp together and dip the whole thing in resin / lacquer. If your after 24volts DC your best bet is Audio Amplifier as they often contain 32volt+ transformers with decent current and using an LM317 and some current pass transistors to make a linear PSU. The LM317 will regulate your voltage the transistors will pass your extra current as its only 1.5A MAX via the LM317 and since you junked a Amplifier to do it you will find the power transistors your need to pass the current, there are a lot of circuit designs you can use. OH yes you can use the heatsink from the amplifier. electronicsarea.com/20-amp-variable-power-supply-using-lm317/
Behind every successful project hides a 100 failures along the way 😅 Where I live, we have an annual hard waste day, where people put out all their accumulated waste such as old appliances etc. Lots of opportunity for people like me to salvage many goodies. Lots of things with transformers.
Thanku for the motivation,there are a few more bridges I haven't jumped off yet.as always please make monty bacon,"bacon helps" l could stand some too.😃
@generalingwer4341 ha ha yes, it's amazing what folks throw out. Year before last I picked up a mains voltage regulator, which is a good quality variac with motor driven brush assembly and feedback circuitry to maintain regulation.
@generalingwer4341 Yes, bacon for Monty and a littke for me. Gotta be crispy. Enjoying your content and, although I've been in the electrical game for a long time, I'm impressed by your knowledge and ability to communicate ideas. Were you a teacher by chance ?
@@lindsaybrown7357 no never was.actually spent many years in various construction jobs when electronics jobs went away in 90s ..had a friend I worked with,he later went on to teach at a electronics school. smartest man I've ever known in electronics.funny thing ,i dont think he ever went to college..life full of regrets that we couldn't spend much time together.when I heard he was teaching, I thought oh my,I'd give anything to be there.🙂😀
@@SkippiiKai yes it was alum.these are very cheaply made for microwaves.ive found much info to support that.it maybe possible though that a xfmr from a real expensive oven could be copper?thanku for your comments🙂.
I have few hundreds of pounds all sizes of power transformers that I'm planning to take the recycling center, if you live or know someone lives near Rochester NY come over and get as many as you wish for free.
Wow.thats a very kind comment.if I was within 60miles of you,I'd be there and pay fair price.thats a shame. I'm in South Central pa.list them on ebay.it would be a hard sell without the data on them or atleast voltages.shipping is inflated too,that makes it hard sell.thanku for comment😃👍.
@@generalingwer4341 I can check the voltages and estimate the power based on weight but as you have mentioned shipping became so ridiculous to the point that it doesn't worth it
@@FariSamSoli yeah, I know shipping is much of problem on ebay too.item cost is third of shipping.real shame this kinda stuff is disappearing. their use to be a local guy in early 90s who had a house full😃
"Wow that's not gonna work"... seems like a pretty useless transformer??.funny thing is I've seen people wrap speaker wire on them😲huh,wonder how long until it melted🤔.
Those copper parts you were confused about are the remains of the third winding: the magnetron heater coil, which is around a 3vac output.
Ok.i was perhaps a bit confused over those 4? Coppers.i didn't remember what I had before I cut the sides flush.i didn't perceive them as actual remains of windings.im gonna have to find another one to see what wires come off it.lol.thanku!😃
These are run into saturation to squeeze more power from them in the oven, the output of the magnetron is 600W and they are around 65 percent efficient so they are pulling 1kW plus from this tiny transformer, those are magnetic shunts and are there to allow leakage flux and therefore limit the output current you need to add turns to the primary or run a lower input voltage , the current is going into reactive power and heating the core, you could also run a series inductor (ballast), also a parallel PFC cap with help with idle current
@@T2D.SteveArcs thanku very much for the info😃
@@generalingwer4341 no problem 👍🏻👍🏻
MOTs are usually rated by their output current, I believe, but I think only half of mine actually have a rating on the transformer itself. The microwave's rating is the magnetron's output power.
As someone else said, remove the magnetic shunts. I believe they reduce the flux in order to prevent core saturation which you won't need to worry about. But MOTs are ultimately just very inefficient transformers. They use silicon steel laminates where should be insulatated from each other, but the magnetic fields in them are so strong that they weld the laminates together in 2 places so they don't push the whole thing apart. This results in edfy currents that draw extra power and heat up the core. If you want less power draw at idle while using that core, you'll need to increase the reactance of the primary by adding more turns. Alternatively, you could run it at a higher frequency, but that's probably impractical in your situation.
Your calculations about volts per turn might be off a bit. Make sure you test the input voltage right on the primary. I wouldn't be surprised if you're quite a bit below 120Vac on the primary, *especially* under a load.
@@SkippiiKai no volts per turn was on.🙂
The microwave(plate) it's self "should be rated by its input power"if It wasn't a person would never know," is my/this receptacle sized for the load".im gonna look into this though.🙂
I do not know why transformers are difficult for you to get but is not difficult.
Location🙂
Pick a neighborhood or an apartment complex and check every evening at a dumpster or side of a street, people leave them out all the time.
If you did not knock the shunts out it will draw way too much current. Knock those out and it will be golden.
Ok thanku so much🙂.i have knocked them out now.i also added turns on primary as well.tomarrow I'm gonna retest.thanku for your comment and for watching🙂.
I was just about to say that as they where there and add another strand to the secondary winding for the 18v also i would have some insulation between the layered wraps use like tracing paper, I have made many of these for same reason but i was going for 14.8DC, when you finished your wraps dip into a lacquer or some sort of light resin, do not add to the primary as its not needed and if you added turns to the primary you will get less voltage on your secondary anyway.
"to fill you gaps well you could add more strands to your secondary in parallel try to get them as even as possible like they are a multi-stranded cable".
That 4 rows of copper you pulled out is another winding i forget its exact use but feed back.
The other thing before you do any resin or lacquer make sure you blown out the transformer as much as you can as there might be some filings in the primary and if there is any enamel off of that copper on the primary it could short it, but yes microwave transformers have high eddy currents due to the fact they are welded laminated core the only solution with that to get the best results is more work where you grind out the welds and take the E and I lamination apart and lacquer them and re-assemble and clamp together and dip the whole thing in resin / lacquer.
If your after 24volts DC your best bet is Audio Amplifier as they often contain 32volt+ transformers with decent current and using an LM317 and some current pass transistors to make a linear PSU.
The LM317 will regulate your voltage the transistors will pass your extra current as its only 1.5A MAX via the LM317 and since you junked a Amplifier to do it you will find the power transistors your need to pass the current, there are a lot of circuit designs you can use. OH yes you can use the heatsink from the amplifier.
electronicsarea.com/20-amp-variable-power-supply-using-lm317/
@@blackIce504thanku for comment🙂keeps deleting my typing so I'm gonna be short👍🙂.
Behind every successful project hides a 100 failures along the way 😅
Where I live, we have an annual hard waste day, where people put out all their accumulated waste such as old appliances etc.
Lots of opportunity for people like me to salvage many goodies.
Lots of things with transformers.
Thanku for the motivation,there are a few more bridges I haven't jumped off yet.as always please make monty bacon,"bacon helps" l could stand some too.😃
I need to move🙂
@generalingwer4341 ha ha yes, it's amazing what folks throw out.
Year before last I picked up a mains voltage regulator, which is a good quality variac with motor driven brush assembly and feedback circuitry to maintain regulation.
@generalingwer4341
Yes, bacon for Monty and a littke for me. Gotta be crispy.
Enjoying your content and, although I've been in the electrical game for a long time, I'm impressed by your knowledge and ability to communicate ideas.
Were you a teacher by chance ?
@@lindsaybrown7357 no never was.actually spent many years in various construction jobs when electronics jobs went away in 90s ..had a friend I worked with,he later went on to teach at a electronics school. smartest man I've ever known in electronics.funny thing ,i dont think he ever went to college..life full of regrets that we couldn't spend much time together.when I heard he was teaching, I thought oh my,I'd give anything to be there.🙂😀
You took out the... Aluminum? What aluminum?
The aluminium from the secondary winding.
@@generalingwer4341 The secondary wire is aluminum and not copper? That doesn't seem right. I'm going to have to check some of mine later tonight.
@@SkippiiKai yes it was alum.these are very cheaply made for microwaves.ive found much info to support that.it maybe possible though that a xfmr from a real expensive oven could be copper?thanku for your comments🙂.
I have few hundreds of pounds all sizes of power transformers that I'm planning to take the recycling center, if you live or know someone lives near Rochester NY come over and get as many as you wish for free.
Wow.thats a very kind comment.if I was within 60miles of you,I'd be there and pay fair price.thats a shame. I'm in South Central pa.list them on ebay.it would be a hard sell without the data on them or atleast voltages.shipping is inflated too,that makes it hard sell.thanku for comment😃👍.
@@generalingwer4341 I can check the voltages and estimate the power based on weight but as you have mentioned shipping became so ridiculous to the point that it doesn't worth it
@@FariSamSoli yeah, I know shipping is much of problem on ebay too.item cost is third of shipping.real shame this kinda stuff is disappearing. their use to be a local guy in early 90s who had a house full😃