03-27-2017 04:04 PM - edited 03-27-2017 04:10 PM
I've set up a simple test circuit (attached) to check on a problem that appeared in a 3phase circuit I was simulating.
This parallel test circuit has a resistive branch with a current reference probe, then two further branches using the Z=A+jB and Z=A-jB blocks.
I expected the Z=A+jB block to give a lagging current (inductive) with negative angle and vice-versa for Z=A-jB (capacitive).
But the probes in the attached example perform in the opposite way. Can someone please shed some light on this.
Attached as image and MS14 files.
Using version MultiSim Education v14.0.0 (14.0.593). I saw another post re current measurement errors in this version. Related?
03-27-2017 04:41 PM
I did a further test to check on the Z_load elements, using discrete RC elements in one branch and RL elements in another branch.
But this gave the same error with +/- phase angles for current.
The oscilloscope appears to show the same problem as the probes, with the current in RC branch lagging the supply voltage?
04-07-2017 04:09 PM
Hi brentp,
I think the circuit it is correct. "L" leads to a positive phase, and "C" leads to a negative phase. ( http://hyperphysics.phy-astr.gsu.edu/hbase/electric/impcom.html#c1)
04-09-2017 07:01 PM
Thanks for the reply and yes I agree with your definitions of +/- angle for the impedance.
But I'm expecting to see the opposite polarity for the current measurements, given a voltage reference at 0deg
and I=V/Z or I=V.Y
then I must be in phase with Y, which is the reciprocal of Z, hence with an opposite +/- angle.
Interested to see if others duplicate this issue or is there something else missing?
04-10-2017 09:20 AM
Hi brentp,
This is the result that I am getting: