Questions tagged [magnetic-flux]

The sum normal component of a magnetic field passing through a surface.

164 questions
Filter by
Sorted by
Tagged with
39 views

Disconnected wire still lit Tester turns on

I have multiple wires going through an electrical PVC conduit. Two phase wire carrying 220v AC of 1.5mm gauge. Two neutral wire carrying of 1.5 mm gauge. One wire for earthing (grounding) of 1 mm ...
70 views

How does balancing currents within a cable or conduit cancel its magnetic fields?

I know the NEC requires all current carrying conductors of the same circuit to be included in the same cable or conduit [300.3(B)], but why? I think it is because the magnetic field generated by ...
113 views

Does coil winding impact current direction? (Lenz Law)

When a magnet is moving toward a wire loop north-side first, the current goes counterclockwise according to the magnet's perspective, as shown in the image below from Wikipedia. Now, consider a ...
• 33
26 views

Why can we say $F=\phi R=NI=HL$ according to $V=IR$?

Magnetomotive force is a quantity appearing in the equation for the magnetic flux in a magnetic circuit,this is the explanation of Magnetomotive force from WIKI : https://en.wikipedia.org/wiki/...
53 views

Why is a DC motor's back EMF constant for a given RPM

I was trying to prove this mathematically from the definition of EMF being the change in magnetic flux over time. Starting with $$\Phi=BAcos(\theta)$$ Then differentiate w.r.t time (assuming B field ...
56 views

What happens to the permanent magnet flux of this synchronous motor?

Considering a synchronous motor with permanent magnets (1 pair) If there is a synchronous motor with permanent magnets and I was given the initial permanent magnet flux Y_mp = e0(at 15 rps) / w (at 15 ...
• 29
101 views

Automatic metal detector using an Arduino

I did a project on automated metal detector, but I am not clear on the circuit. I built the circuit connecting a resistor to pin A4 on the Arduino, and a diode capacitor setup in series too. I don't ...
41 views

Confused about the core flux waveform (and by extension the magnetising current waveform) of a current-fed push-pull DC-DC converter

I was going through the above converter and cannot understand how the flux in the transformer core changes (and by extension the magnetizing current). According to the text I'm reading, there are ...
81 views

Electromagnet force and magnetic permeability

In a cylindrical core electromagnet, Magneto-motive force (MMF) = 613 At Magnetic strength (H) = 15345 At/m I am using an iron core with 10% silicon in it, so the saturation magnetic flux density of ...
124 views

Audio Engineer needed to read 14-track magnetic tape

I have a 20 mm magnetic tape, with 14 channels. The data tape does not have any sound and format in which data has been stored on tracks is as follows. The picture of tape head is as follows. The ...
• 11
57 views

Shielding AC magnetic field using cable shield connected to two grounds

I am currently reading a book about electromagnetic compatibility but I am confused about a section that talks about reducing the coupling between an external magnetic field $B_{ext}$ and a circuit ...
• 159
70 views

Does a certain cable arrangement that reduces the generated magnetic field improve shielding properties as well?

If I arrange a three phase cable via phase-split into an arrangement that reduces the generated magentic field, does this affect shielding properties as well? To reduce the generated magnetic field of ...
1 vote
48 views

Direction of magnetic flux of mutual inductance where coupling coefficient is almost 1

I've drawn the below diagram of the circuit. We will handle the system as the switch is closed . The coupling coefficient of the system is almost 1 I assumed $~ L_{1} ,L_{2},M ~$ are all positive ...
46 views

Ampere's Law with dielectric

I am asked to calculate the magnetic-field-strength and magnetic-flux-density for different regions inside a coaxial-cable. I found Ampere's Law for that, but it uses $\mu_0$ , and the coaxial-cable ...
52 views

Using a signal generator and power amp to supply >>240VAC to a coil

On Lenz's law, Wikipedia says: Faraday's law states that the EMF is also given by the rate of change of the magnetic flux where epsilon is the electromotive force (EMF) and $\phi_B$ is the magnetic ...
76 views

Transformer Zero Flux Approximation

I have a question about a standard approximation made about the magnetic flux in transformer analysis. Using the magnetic circuit model, the sum of the magnetomotive forces in a transformer are:  \...
• 1
34 views

How does mutual flux in a synchronous generator remain constant like in a transformer?

Given is the flux per pole of of a synchronous generator 1)Is it field/rotor flux per pole ? 2)The generated emf per phase is given by E=4.44Nfφ where φ is the flux per pole But from transformers, we ...
603 views

Why does inductor core saturation depend on the temperature?

For example at room temperature (20ºC) the saturation current is 450mA and with 100ºC the saturation current is 350mA. What causes this? (Edit) The higher inductance with higher temperatures and lower ...
55 views

Physics behind current direction in a transformer on HF

Let's consider the following schematics: According to the model, the current in the secondary winding always flows in the opposite direction than in the primary anywhere in 1-30 MHz range: Could you ...
1 vote
185 views

Why does the rotor magnetic field lag the rotor current by 90° in a 3 phase induction motor?

I was trying to understand load angle in electrical machines, generally denoted by delta, and I found out that while delta needs to be less than 90° in synchronous machine for steady state stability, ...
1 vote
54 views

What effect in the current will have the change of the diameter of coil but same length of coil and same magnetic flux?

First image is one coil with the large diameter and a magnet rotating to create current in the coil. Second image is the same set but the diameter of coil is smaller.
• 139
84 views

Magnetic flux density in a point

This is a single phase copper line in the next configuration So its asked to find the magnetic flux density internal and external due $I_{A}$ and $I_{B}$ affecting the A cable and measured in ...
• 431
784 views

What exactly carries energy in a transformer from primary to secondary? [duplicate]

Suppose we have applied a voltage to a transformer with an open secondary, we will get a certain flux in the core and a certain voltage at the secondary depending upon the turns ratio. Now, suppose we ...
57 views

Flyback power supply - 132 kHz radiated magnetic field issue

I request your expertise on a radiated magnetic field around 132 kHz (low frequency) on a Flyback power supply. I'm using the LNK3694 driver with a switching frequency around 66 kHz. Using a circular ...
1 vote
193 views

• 95
105 views

The results of my magnetic flux data from voltage recorded

For my electrical engineering senior design I created an experiment to test magnetic flux (more voltage) through a receiving coil. There is a large sending coil with A.C. voltage and a small receiving ...
• 95
579 views

How to calculate rotor flux of the three phase squirrel cage induction motor?

I have a three phase squirrel cage induction motor with given parameters (stator winding connected in delta) nominal power: $P_n = 22.4\,\mathrm{kW}$ nominal stator voltage: \\$V_{sn} = 230\,\mathrm{...
• 845
1 vote
59 views

Is mmf the same as the magnetic force?

In the following system, I created the following equation in terms of what I assumed to be the force acting on the movable object with a mass M. The reluctance of the core is neglected, so the total ...
41 views

Transverse Flux Machine

For research, I want to build a levitation system that can levitate an aluminum sheet. With traditional 3 phase Induction engines you off course get levitation, but it isn't as stable as I want to. I'...
1 vote