Why is the mutual inductance term negative in the loop equations?

AI Thread Summary
The discussion revolves around the confusion regarding the sign of the mutual inductance term in loop equations for a circuit. The user initially set up the equations but was informed that the mutual inductance term should be negative. They clarified that their model for current I2 is entering the dot and I3 is exiting, which led to questioning the application of the mutual inductance sign convention. The user speculated that the issue might stem from the polarity of a voltage source in their analysis. Ultimately, they concluded that adjusting the loop equation for I1's direction resolved the confusion about the mutual inductance term.
xxXen0xx
Messages
2
Reaction score
0
http://img638.imageshack.us/img638/989/newbitmapimagety.png
I am running my loop current equations for this circuit and have.
-1+-j6*(I1-I2)=0
-j6*(I2-I1)+j20*I2 +j12*I3=0
(j30-j2+j5+4)*I3+j12*I2=0

But i am being told that the mutual inductance term j12 should be negative in both.
My model current I2 is going into the dot and I3 is coming out of the dot, so
jwL+M=0 should apply
not
jwL-M=0

what am i missing?
o wait... is it the sign of the 1V i have backwards?
 
Last edited by a moderator:
Engineering news on Phys.org
what is the question?
 
I am reviewing questions from old studies.
I believe it was to find Zeq at the terminals of the left hand inductor, by using a 1V test.
But i think I answered my own question.
For I1 running from - to + potential the loop equation needs to read
1+-j6*(I1-I2)=0
so that second loop equation is
-j6*(I2-I1)+j20*I2 +j12*I3=0
 

Thread 'Underwater piezoelectric sensor array receive sensitivity'

Hi all I have some confusion about piezoelectrical sensors combination. If i have three acoustic piezoelectrical sensors (with same receive sensitivity in dB ref V/1uPa) placed at specific distance, these sensors receive acoustic signal from a sound source placed at far field distance (Plane Wave) and from broadside. I receive output of these sensors through individual preamplifiers, add them through hardware like summer circuit adder or in software after digitization and in this way got an...
View full post »

Thread 'Following up on the recent thread about Earth Resistance measurements'

I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
View full post »
Thread 'Beauty of old electrical and measuring things, etc.'

Thread 'Beauty of old electrical and measuring things, etc.'

Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Two views of the gadgets shelves and my small work space: Here's a close up look at the meters, gauges and other measuring things: This is what I think of as surface-mount electrical components and wiring. The components are very old and shows how...
View full post »

Similar threads

Mutual Inductance dot convention?
Replies
8
Views
15K
Why Are My Kirchhoff Voltage Rule Equations Incorrect?
Replies
1
Views
1K
Trying to model mutual inductance with losses
Replies
1
Views
2K
Solving Current & Power in 4 & 3 Wire Circuits
Replies
9
Views
2K
Power dissipated in this circuit with 2 batteries and 3 resistors
Replies
22
Views
4K
Understanding Loop Currents: Why is I3 Negative?
Replies
1
Views
1K
Engineering AC Circuit Phasors: Find I1, I2, I3
Replies
26
Views
3K
Can Mesh Analysis with Three Loops Solve a Four-Loop Circuit?
Replies
9
Views
2K
Writing Kirchhoff Rules for a Multi-Loop Circuit
Replies
5
Views
3K
Parallel transformers - checking my models
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top