I have a few questions regarding transformers. Firstly, I really like the site's description as to how transformers work. I'm a checmial engineer that taught myself electronics and have only encountered texts(Horowitz Hill, Halliday Resnick Physics, and a Technicians Electric Circuits book) that mention basic transformer calculations but have never got a good description how they really work IE: magnetomotive force. It seems one can go far in an EE education knowing only the inductor(emv=di/dt) and primary secondary transformer relations (V, I, R) as a function of turns ration w/o knowing anything detailed about the magnetic phenomena
Most of the text that I've seen basically makes it look that when there is no current in the secondary - there's no current in the primary. This can't be true - an unloaded secondary will mean that the primary still looks like an inductor w/ reactive current. I would like to go beyond this simplification.
1. Can you recommend additional web text that describes tranformer action? Or can you recommend a good book that gives a good introduction to transformer action that goes beyond simple turns scaling? I basically would like to model ideal transformer action to fully understand counter mmf setup by a loaded secondary and it's impact on primary voltage/current/mmf and magnetic circuit.
2. I'm trying to visualize what happens when a resistor is placed across the secondary. Starting with the MMF created in the primary & unloaded secondary - when the secondary is resistively loaded, a load MMF is created in the second which means an additional anti-load MMF is created in the primary - altering the V-I in the primary? In other words, there are two mmfs in the primary and one in the secondary such that for the magnetic circuit: (1/2 coil location of mmf)
mmf1(due to voltage source) + mmf2(due to load) - mmf1(due to load) = mmf1(due to voltage source)
3. Suppose you had a piece of metal that's not magnetized. How to do an energy balance taking into account work required to permanently magnetize the metal.
Any text/web suggestions as to where I can get additional info - I would appreciate.
Thanks,
Monty
Most of the text that I've seen basically makes it look that when there is no current in the secondary - there's no current in the primary. This can't be true - an unloaded secondary will mean that the primary still looks like an inductor w/ reactive current. I would like to go beyond this simplification.
1. Can you recommend additional web text that describes tranformer action? Or can you recommend a good book that gives a good introduction to transformer action that goes beyond simple turns scaling? I basically would like to model ideal transformer action to fully understand counter mmf setup by a loaded secondary and it's impact on primary voltage/current/mmf and magnetic circuit.
2. I'm trying to visualize what happens when a resistor is placed across the secondary. Starting with the MMF created in the primary & unloaded secondary - when the secondary is resistively loaded, a load MMF is created in the second which means an additional anti-load MMF is created in the primary - altering the V-I in the primary? In other words, there are two mmfs in the primary and one in the secondary such that for the magnetic circuit: (1/2 coil location of mmf)
mmf1(due to voltage source) + mmf2(due to load) - mmf1(due to load) = mmf1(due to voltage source)
3. Suppose you had a piece of metal that's not magnetized. How to do an energy balance taking into account work required to permanently magnetize the metal.
Any text/web suggestions as to where I can get additional info - I would appreciate.
Thanks,
Monty