Thanks to all of you for your answers. In the meantime I managed to talk about this problem with my ex-faculty-professor. He is "an expert" regarding the transformers and he told me that if I want to have a zero residual flux I should use decreasing AC excitation. He said that by using...
Thanks prc for the reply.
I am doing some measurements on a laboratory set-up, i.e. I am switching on the network that comprise the transformer. It would be very important that I would be sure that the residual flux is the same at the beginning of each measurement, i.e. before each switching...
Thanks for all advices and I understood the method with decaying AC excitation. However, I would like to know one more detail about method with applied DC-current.
Namely, if I apply some current of a moderate percentage of the transformer's nominal current I would direct the domains in one...
Thanks itsmoked for the clear answer :-)
However, Skogsgurra said that if I would decrease applied current to zero the residual would not decrease to zero and however I feel that this is in a some kind of contradiction with your answer.
Namely, could please anybody explain how is it possible...
Thanks for the answer! But how about setting some fixed value of flux by applying DC current to the winding, i.e. it is not clear to me does the flux (after applying DC-current) depends on residual flux which existed before the applying of DC-current?
Hi, I am carrying out some switching measurements on a one-phase transformer and it would be very important that I could set the same residual flux before each measurement.
For instance, could I use DC-source so that through the winding flows DC-current that would set residual flux to some...
Hi, I am carrying out some switching measurements on a one-phase transformer and it would be very important that I could set the same residual flux before each measurement.
For instance, could I use DC-source so that through the winding flows DC-current that would set residual flux to some...
Im using chopper with 50Hz frequency. But my DC-motor has time constant L/R=1ms and thats much smaller then 20ms (chopper period). Because of that, armature motor current isnt constant, and with every "chopp" armature current falls to zero and goes up again (exponential-like)... and so...
i need axis (i hope thats the name...my english isnt very flexible ; ) for a DC motor. on this axis will be human organ and this organ will be "scaned" with ultrasound. so i need material for axis that will be unvisible on ultrasound pictures. this organ and whole imaging is happening...
i need axis (i hope thats the name...my english isnt very flexible ; ) for a DC motor. on this axis will be human organ and this organ will be "scaned" with ultrasound. so i need material for axis that will be unvisible on ultrasound pictures. this organ and whole imaging is happening...
you may noticed: i made "stupid" mistake but then i corrected it: speed is proportional to armature voltage, torque to armature current...
ok, all that stuff about constants..but that isnt so important to me, i know: that are DIFFERENT CONSTANTS... so thank you... that was another my...
i use chopper to control speed of DC motor. i assume: with chopper i decrease armature current (its constant), but armature voltage is "jumping and falling". Well, torque is proportional to armature current and speed is proportional to armature current. It isnt clear to me: difference...
