and what happens if a transformer designed for 120-V ac is connected to a 120-V dc line?
2007-05-09 22:27:29 · 6 answers · asked by wtfitsnguyen 2 in Science & Mathematics ➔ Physics
It will not work.
And the primary coil would get extremely hot due to the constant current you are putting through it with no 'load' attached.
Transformers require a changing magnetic field in order to induce current in the 2nd coil - remember the coils are not directly connected, it is the changing magnetic field which does the work.
By alternating the Voltage & Current, we change the magnetic field aswell, hence the tranformer works; this is a good example of electromagnetic induction - which Michael Faraday did loads of work on.
2007-05-09 22:34:09 · answer #1 · answered by Doctor Q 6 · 0⤊ 0⤋
No. It will not work as the flux is not changing. It will only give a pulse during the time the current is rising and then there will not be any secondary voltage.
Transformers have high reactance and very low resistance. If you connect dc to the transformer, the current will go sky high and will damage the transformer.
In fact a transformer carrying 1500 A of AC current can be damaged if you superimpose about 15 A of dc current in the ac current.
2007-05-10 06:51:42 · answer #2 · answered by dipakrashmi 4 · 0⤊ 0⤋
To answer your basic question !! what you must do is first chop the DC into small segments , then this voltage ( pulsating DC ) can be applied to the primary of a transformer , various voltages can then be taken off the transformers secondary windings ! .
Second part of your question as to what happens if you connect 120v DC to a transformer winding , well you would get a smell and burning and failure of the transformer just like the other respondents have already said .
Cheers Pete
2007-05-10 06:10:49 · answer #3 · answered by Realist 2006 6 · 0⤊ 0⤋
first q:
no, applying 'dc' to a transformer sets up an electromagnetic field in the core.after the core saturates,current will flow,relative to the resistance of the winding.
second q:
assuming a 120 vac transformer,after the above, high current
in the primary winding will cause overheating..
(don't try this)
2007-05-10 05:48:06 · answer #4 · answered by daniel g 7 · 0⤊ 0⤋
It can't couple energy to the secondary so usually it burns up.
2007-05-10 05:36:11 · answer #5 · answered by Gene 7 · 0⤊ 0⤋
(1) No. (2) It will certainly melt and may even catch fire.
2007-05-10 05:46:19 · answer #6 · answered by rrabbit 4 · 0⤊ 0⤋