20
votes
Accepted
Are induction stoves considered inductive loads?
An induction stove isn't just an inductor connected across mains. A typical stove rectifies the mains power into DC, and drives the coils at a high frequency (tens or hundreds of kHz) through a ...
- 316
15
votes
According to my understanding, this induction heater should be melted, but it's not. Why not?
Where do you find that a 12 AWG wire is rated for just 30A?
That may be true for standard, PVC-insulated wire used for home electrical systems.
The ampacity of a wire doesn't depend solely on wire ...
14
votes
Accepted
"Where" does back EMF appear in motor?
The back EMF is generated in the wire that makes up the coils of the motor. When a wire is swept sideways thru a magnetic field, a voltage is generated along the length of the wire. Spin the motor ...
- 314k
14
votes
Are induction stoves considered inductive loads?
Found this from the 2014 report "Induction Cooking Technology Design and Assessment"
https://www.aceee.org/files/proceedings/2014/data/papers/9-702.pdf
It was presented at the 2014 ACEEE ...
- 5,027
13
votes
Accepted
Why does a timing light connect to 12 V?
It's for power. The power from the magnetic pickup is very small. It's basically a signal, not something you can run a light from directly. The 12 V and ground connections provide the power. This ...
- 314k
13
votes
According to my understanding, this induction heater should be melted, but it's not. Why not?
The coil winding is cooled with forced air (fan). You can likely hear the fan working when the heater is on. How do I know? I have opened several of the small induction units to repair.
Your photo ...
- 5,269
12
votes
Can two voltmeters connected to the same terminals show different values? Circuit with induced EMF
YES, two voltmeters connected to the very same couple of terminals can simultaneously show two different values.
The reason is that, since the circuit path is enclosing a variable magnetic flux region,...
- 4,118
12
votes
Accepted
Intuitive way of "visualizing" how the energy is stored in an inductor?
I'm going to start by discussing capacitors then move to inductors. I'll avoid complex equations (to save myself as well as this discussion.) I may even discuss duals between capacitance and ...
- 78.5k
11
votes
Accepted
If you have two identical but oppositely wound inductors does the inductance effectively cancel?
It depends of the extent of their mutual inductance. Roughly speaking, if they are wound on the same ferrite core, they have a large proportion of their inductance that is mutual (as in a transformer ...
- 343
11
votes
Why can domestic induction stoves heat aluminium tape, but not aluminium pans?
Induction stoves induce eddy currents in objects placed on top of their varying magnetic field. The heating effect size is determined by the conductivity of the object. Too low (say a ceramic pan) ...
- 7,906
8
votes
Why does a timing light connect to 12 V?
Back in the olden days, ignition timing lights were neon lamps powered off the ignition pulse. They were so dim as to be almost useless (unless you were into performing engine maintenance at night, ...
- 19.6k
8
votes
Heating a tube of aluminium electrically
Because your tube temperature is expected to be less than 100 C, resistive heating should be quite simple. Use a single wrap of something like Sil-pad silicone sheet around the tube, then wind your ...
- 60.8k
8
votes
According to my understanding, this induction heater should be melted, but it's not. Why not?
As there are presently other answers answering the direct question, I will just address the remaining confusion:
The work might indeed be carrying hundreds of amperes; how much depends on the coupling ...
- 43.7k
8
votes
3 phase induction hob, single phase wiring
Your assumption is very far off. Please don't try to wire it yourself. You can't connect a stove requiring three phases with an outlet that provides one phase.
The stove requires three phases. The ...
- 165k
8
votes
Why does a 1:1 transformer preserve voltage?
If two coils have the same magnetic flux in common, and they have the same number of turns, then the emf generated in each is the same. If you neglect parasitic effects, such as the resistance of the ...
- 26.2k
7
votes
Accepted
How does the diode work out the reverse voltage spike of DC motor?
When does the motor do that, in this circuit? Is it when the switch is powered off (by having GND to the base)? If so, if I do a PWM with the transistor switch, would it occur a hundred times a second?...
- 46.9k
7
votes
Is magnetic flux in a transformer proportional to voltage or current?
You should make a clear distinction between magnetization flux (a nearly constant AC quantity made by the primary) and, the naturally cancelling fluxes from the primary and secondary windings (that ...
- 467k
6
votes
Heating a tube of aluminium electrically
I'd suggest hot air as safest. I do not see why it could not be made uniform, unless your tube is longer than a meter or so. Aluminum has extremely good thermal conductivity, you'd be pressed hard to ...
- 13k
6
votes
Accepted
Heating a tube of aluminium electrically
If you need temperature uniformity along the tube surface, your most reasonable choice is #2 - wirewound resistive heater. Peltier cooler is absolutely out of question, mostly due to their standard ...
- 41.9k
6
votes
Can I use rectified AC current to heat an object inside a induction coil?
What you are really trying to do is add DC bias current so that the coil current never has a zero crossing. This is misguided. The losses in the coil are basically entirely resistive, and will be a ...
- 29.4k
6
votes
How do induction cookers measure temperature?
At least some of them appear to have a silicon thermistor set in the center of the induction coil and (probably mostly radiatively **no, see below) thermally coupled to the pot.
Here is a photo of a ...
6
votes
Accepted
A question about Faraday’s law of induction for a closed path
The integral form of Faraday's law is \$\oint\vec{E}\cdot dl = -d/dt\oint\vec{B}\cdot d\vec{s}\$
Knowing the magnetic flux through your loop, you can calculate the voltage around the loop.
The ...
- 1,379
6
votes
Accepted
Why this motor shows delta 220 / star 380 which is usually the other way round from what I know?
You're mistaken.
The motor phase voltage is 220 V.
When connected in star, the line voltage is 220 * √3 = 380V.
When connected in delta, the line voltage is the same as the phase voltage i.e. 220 V.
- 19k
6
votes
Accepted
Why we use constant value of magnetic flux in transformers
Secondary load current \$\times\$ secondary turns is exactly cancelled by the load current flowing in the primary \$\times\$ primary turns hence, fluxes associated with the secondary load are ...
- 467k
6
votes
Why we use constant value of magnetic flux in transformers
Think of the transformer theoretical model (without parasitic elements):
simulate this circuit – Schematic created using CircuitLab
The ideal transformer (IDEAL TX above) has infinite ...
- 38.1k
6
votes
Why does a 1:1 transformer preserve voltage?
It comes from Faraday's law of indcution.
If a certain AC voltage with a certain number of turns causes a certain magnetic flux in the core, then in reverse, this same magnetic flux causes an equal AC ...
- 165k
Only top scored, non community-wiki answers of a minimum length are eligible