I have a few general questions about transformers from a couple of basic experiments I have conducted. I can find very specific and detailed information online, but not a general rough explanation of what going on. Ill try to keep things as clear as possible.
I have recently been mucking about with transformers and Im just wondering;
Why do larger Microwave oven transformers, when powered from a 12V 100W supply, have a higher output drop off than smaller transformers when loaded?
For example, MOT 1 produced 227V from 12V, but when I tried to power a small 18W 120VAC MO fan It barley rotated output down to just 38V, and with MOT 2 107V output down to 21V and the fan didn't move.
But when I use a midsized centre taped step down (wired in reverse) A 190V output drops only to 90V and the fan rotates with vigour, drawing 3A from the 12V supply.
I use this transformer and fan when soldering to blow away the fumes, the transformer gets quite warm after extended use.
The diagram also includes the coil resistances.
What factors are at play? And what information is needed to estimate this effect?
But from these very basic experiments Im also wondering why doesnt wiring transformers secondary into the primary of another and so on produce stable very high voltage?
CTSD transformer, stepping up into MOT1, doesnt work, MOT1 has a similar/same output as if its connected directly to 12V, upon investigation the first transformer has it output dropped right down to the 12V on the input. Only when I use the two MOTs one stepping up into the next to I get around 2kV put it drops sharply with any type of loading.
Finally, and this is the one that has me most baffled, when using a small wall plug adapter 12VA AC wired in reverse as a step up 12V input to 207V unloaded. Loading with the fan gives 70V output, this is enough to power the fan but there is almost 3 times the rated current trough the transformer, it gets hot and begins to fail.
Its the nature of the failure I dont understand. The fans speed after a small amount of time beings to fluctuate eventually slowing right down, But voltage remains constant!
The 12V in and the 70V output slowly drops to 64V, but not necessarily at the same time as the fluctuations.
Im assuming it has something to do with the increase in temperature but I have no idea how this is happening and would not know how to begin to ask it.
Both the fan and the power supply seem robust.
If this type of effect has been discussed before point me it that direction, if there are external links that are relevant include them.
My first question is the main one. If you have any opinion any way related feel free to chime in!
Thank you for your time and wisdom.
I have recently been mucking about with transformers and Im just wondering;
Why do larger Microwave oven transformers, when powered from a 12V 100W supply, have a higher output drop off than smaller transformers when loaded?
For example, MOT 1 produced 227V from 12V, but when I tried to power a small 18W 120VAC MO fan It barley rotated output down to just 38V, and with MOT 2 107V output down to 21V and the fan didn't move.
But when I use a midsized centre taped step down (wired in reverse) A 190V output drops only to 90V and the fan rotates with vigour, drawing 3A from the 12V supply.
I use this transformer and fan when soldering to blow away the fumes, the transformer gets quite warm after extended use.
The diagram also includes the coil resistances.
What factors are at play? And what information is needed to estimate this effect?
But from these very basic experiments Im also wondering why doesnt wiring transformers secondary into the primary of another and so on produce stable very high voltage?
CTSD transformer, stepping up into MOT1, doesnt work, MOT1 has a similar/same output as if its connected directly to 12V, upon investigation the first transformer has it output dropped right down to the 12V on the input. Only when I use the two MOTs one stepping up into the next to I get around 2kV put it drops sharply with any type of loading.
Finally, and this is the one that has me most baffled, when using a small wall plug adapter 12VA AC wired in reverse as a step up 12V input to 207V unloaded. Loading with the fan gives 70V output, this is enough to power the fan but there is almost 3 times the rated current trough the transformer, it gets hot and begins to fail.
Its the nature of the failure I dont understand. The fans speed after a small amount of time beings to fluctuate eventually slowing right down, But voltage remains constant!
The 12V in and the 70V output slowly drops to 64V, but not necessarily at the same time as the fluctuations.
Im assuming it has something to do with the increase in temperature but I have no idea how this is happening and would not know how to begin to ask it.
Both the fan and the power supply seem robust.
If this type of effect has been discussed before point me it that direction, if there are external links that are relevant include them.
My first question is the main one. If you have any opinion any way related feel free to chime in!
Thank you for your time and wisdom.
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