4
If you mean live and neutral AC mains signals then live must be insulated. Neutral is supposed to be at ground potential and thus not a hazard, BUT there are numerous wiring errors and fault conditions that could make a neutral conductor dangerous.
I cannot imagine a design of a product that would not insulate both.
Relying on neutral being at ground ...
4
Yes it can be done, however it may be more economic to use a single autotransformer with multiple taps.
3
Take every precaution possible as 1700 VDC will have no mercy on you. Capacitive leakage in the transformer means isolation is not that safe. Touch the high voltage and it will zap you, possibly burn you. Get used to wearing those gloves.
Do not earth ground as it makes it an unisolated supply.
If you always wear safetygloves the boots are not needed. When I ...
2
The OPA548 is supplying a sine wave at 50 Hz and 16 Vpp.
This won't work. You have not factored in the magnetization requirements when driving the secondary.
Ignoring the primary (high voltage output winding), the secondary acts like an inductor and the inductance will be too low to adequately magnetize the core of the transformer without high reactive ...
2
No, there are no ferrite materials that thermally degrade at 100°C. Even if heated above their curie temperature (this is the temperature a magnetic material looses its magnetic properties entirely and behaves similar to an air gap. Or for permanent magnetics, this completely demagnetizes them), virtually all ferrite materials will regain all their ...
2
In general it's not a problem, but 127VAC * 2 = 254V plus tolerance (and the increase on the 127V will be doubled). So you should go higher than 230VAC rating most likely.
You might also consider using two MOVs the same in series, saving on a BOM item and giving you a 280V rating rather than 230.
2
Magnetizing inductance is not equal to mutual inductance.
It is for a 1:1 transformer. The mutual inductance (the turns that are 100% coupled between primary and secondary) represents the magnetization inductance. Those turns that don't couple are not mutual inductance but leakage inductance. Mutual inductance is \$\sqrt{L_P\cdot L_S}\$ hence, for a 1:1 ...
2
grounding the common doesn't put current into the ground because current only flows in circuits. and as the transformer secondary is isolated there is no circuit through ground
simulate this circuit – Schematic created using CircuitLab
by grounding the trasformer secondary they can use a transformer with only functional insulation. With it isolated ...
2
The intent of grounding the chassis isn't to help with troubleshooting.
People are assumed to be at ground potential and/or connected to ground somehow by virtue of the inability to hover. The chassis is grounded so that if a hot wire gets loose inside and makes contact with the chassis, the current will take the easier path to ground through the low ...
2
We are referring the secondary inductance to the primary to simplify calculations.
For an impedance $$Z = \frac{V}{I}$$.
If any impedance \$Z_s\$ on the secondary is referred to the primary the equation is:
$$Z_p = \frac{V_p/V_s}{I_p/I_s}Z_s = \frac{N_p/N_s}{N_s/N_p}Z_s = \left(\frac{N_p}{N_s}\right)^2Z_s.$$
This can also be checked by calculating a short-...
2
Transformers are difficult to source in general. My recommendation based on past experience designing low volume one-off flyback transformers is to build your design around the transformer, not vice-versa. Coilcraft is an example of a company that sources stock transformers suitable for flyback applications.
I'm providing this as general advice for people ...
2
use fewer turns for the primary, like 3 perhaps.
1
It is presumed that 220V~ 50Hz 2.8A 500W is the rating on the nameplate of a piece of equipment. The rating on the nameplate of an identical piece of equipment, intended for 110V~ 60Hz operation, would be 110V~ 60Hz 5.6A 500W.
1
120 Hz as a test frequency is close enough to 60 Hz to get reasonable results.
The problem when measuring transformer leakage inductance is that you cannot avoid measuring the combined primary and secondary leakages of the transformer i.e. you measure a composite number either referred to the primary (when the secondary is shorted) or referred to the ...
1
Use a relay.
simulate this circuit – Schematic created using CircuitLab
Figure 1. A possible circuit.
The relay separates your 3-phase from your 3.3 V Raspberry Pi circuit making it a safe system.
1
The circuit appears to be based on the MPS MP17x family of offline non isolated power supplies with versions rated at from 60 mA to 600 mA output.
While these ICs are useful, it must be noted that
THE CIRCUIT IS LETHALLY DANGEROUS at all times.
The output is not isolated from AC mains and ALL parts of the circuit should be regarded as being at mains ...
1
The main effects of running a brushed DC motor on unfiltered DC are increased loss and heating due to the higher ratio of rms to average current, and increased noise and vibration caused by the motor changing speed in time with the rectified waveform.
This will reduce efficiency and may reduce longevity, but probably not enough to worry about in most ...
1
There will be some capacitive coupling thru the transformer, from primary to secondary.
This current needs a return path.
The current will be:
I = C * dV/dT
I = 100pF (SWAG) * (377 radian/second * 160 volt)
I = 1e-10 * 60,000 = 1e-10 * 6e+4 == 6e-6
I == 6 microAmps
==============================================
To compute that capacitance, assume the primary/...
1
This is just my thought experiment.
Since Arc Impedance is a low negative resistance (NR), the maximum power (MPT) will be transferred when the arc impedance matches the power supply impedance, but that also means 50% loss so that may not be ideal. It may be a conjugate capacitive conductance of current with a reactor inductive source to make it less lossy.
...
answered Jul 28 at 17:49
Tony Stewart Sunnyskyguy EE75
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1
The square of the ratio of the turns ratio works irrespective of how you drive the transformer. So, if primary is 236 µH and secondary winding has half the turns of the primary then the secondary inductance is 59 µH.
The primary and secondary current slopes will only be equal when using a 1:1 transformer and input and output DC voltages are identical. The ...
1
As Jasen mentioned in his answer use fewer turns, 3 to 6. Bring the voltage up to as high as 24. Plan on mounting Q1 to a large heatsink. You should be able to get arcs of 1/2" (12.7mm). You could get 1 inch arcs but Q1 will get hot - and you risk the transformer arcing internally.
1
The live/phase/active wire. Except that in countries where you can connect the mains plug in any orientation to wall socket, either one of the wires could be the live or neutral, so both.
1
I measured the Vgs on M1 and its a pulse at 5V peak for 250ns.
Just look at the graph in the MOSFET data sheet. This one: -
With 10 volts on gate w.r.t. source it's barely breaking the sound barrier in terms of performance and it's not even listed for a \$V_{GS}\$ of 5 volts.
the datasheet states that maximum threshold voltage is 4V, so one
would assume ...
1
If the core saturates, the CS pin will exceed 1V and cause the controller to latch off after 15ms or something like that, until the power is cycled.
You can monitor the voltage on that pin and see if that is occurring. Also, measure the primary inductance and see if it is as designed (and double-check your design), preferably under bias if your LCR bridge ...
1
It will work fine -- this is basically the way all systems in your house are connected -- the primaries of the individual transformers are in parallel (i.e. plugged into the mains), and the secondaries are all separate.
1
It might help considering all possible cases and then go down to the particular case you are interested in.
Much in the same way as current is the time derivative of electric charge, you should see voltage in a circuit with magnetic elements as the time derivative of magnetic flux.
The voltage you see at the terminals of an inductor is due to the time ...
1
Zero sequence is not DC. The zero sequence component in each phase has the same magnitude and phase angle. They are a set of phasors that rotate counter-clockwise just like all positive frequency phasors. Below is slide with overview of the symmetrical components. Note that i didn't attempt to use the exact real component phasors for the phase quantities ...
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