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1 vote
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Transformer ratio of a transformer that connects a generator to a MV grid?

I try to answer your questions below. how should I modify the transformer ratio when the rated power changes? You should not change the voltage ratio due to the rated power of the generator. ...
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3 votes
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Replacing a virtual ground circuit with center tapped transformer

Would it be fine if I use -12v&+12v instead? No . 12 Vrms values with no load goes 40% to 50% higher Vdc peak. 1.414 times for the rms to peak conversion and 10% typ for transfo losses at rated ...
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4 votes

Why don't simulators work with a self-oscillating voltage booster circuit using a transformer and a transistor?

These sorts of simple self oscillating schemes rely on transformer saturation to define the on time by volt seconds applied to the winding .This is a close relative to the blocking oscillator .You ...
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6 votes
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Why don't simulators work with a self-oscillating voltage booster circuit using a transformer and a transistor?

It's not the simulator that's isn't working. The challenge is to accurately model your circuit: not just its connections, but also the circuit elements. Even then, simulations can bomb out when they ...
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7 votes

Why don't simulators work with a self-oscillating voltage booster circuit using a transformer and a transistor?

The transformer winding in the collector is the wrong way round. You need to swap the two connections such that when the collector goes towards ground, the base goes positive. The dots on the windings ...
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0 votes

Galvanic Isolation in Automotive Environment

Assuming this is what you got... The problem here is the ground loop. The voltage reference for your signal is the "0V" point at the source (in this case the computer playing the music). ...
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1 vote

Help designing a safety indicator for a high current transformer

Knowing if there's any current flow in the secondary (or the primary) doesn't really help much from a safety standpoint. Suppose there's nothing attached to the output, there would be no current flow ...
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  • 3,386
1 vote

Help designing a safety indicator for a high current transformer

There are several companies that make current sensing indicators using a mini CT and LED. These provide electrical isolation up to some point. Wiring it in the return wire on a grounded HV system ...
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2 votes

Help designing a safety indicator for a high current transformer

The most common indicator for a safety no-voltage/current is a low voltage Neon Indicator with 220k current limiting resistor or as desired. https://www.intl-lighttech.com/instrumentation-sensor-light-...
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0 votes

Help designing a safety indicator for a high current transformer

The transformer primary current will be quite small if there is no load on the secondary (high voltage) end. Therefore it is sufficient (and much safer) to monitor the primary (120 V) current. So now, ...
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1 vote

Help designing a safety indicator for a high current transformer

On secondary side it is difficult because the insulation. Much easier it is on the primary side. No voltage on primary side => no voltage secondary.
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0 votes

Can I use common mode power line choke as 1:1 transformer in isolated buck-boost switched mode power supply at 20 - 100 kHz?

Hmm, it would probably work. The downsides to look out for on CMCs are: Core loss: they're intended for low CM voltages, just filtering. Leakage inductance: they're intended for some DM filtering as ...
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0 votes

A couple of questions about transformers

1: I accidentally supplied 9v to a 4.5v - 0 - 4.5v transformer like this Most likely you have burnt it, because you supplied twice the voltage the transformer was designed for. Depending on the ...
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0 votes

AC/DC transformer and isolation

For the record, those people are dangerously wrong First, that graphic was done by nitwits, and is wrong. The nitwits are relying on the concept of "first ground fault is free" when dealing ...
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1 vote

A couple of questions about transformers

You can't supply a signal with a DC component to a transformer. So you can't (shouldn't) apply a 'square wave DC signal' (there's no such thing). If you apply an AC-coupled square wave, you'll get a ...
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1 vote

AC/DC transformer and isolation

I am not sure what is inside your device as it could be either a classic low-frequency transformer followed by a diode bridge or a switching converter - a SMPS - featuring a high-frequency transformer ...
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0 votes

AC/DC transformer and isolation

First, your electronic device does not need ground as it might be double insulated (Class II) appliances. There are at least two types of layers of insulation. Second, as the name of the transformer ...
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2 votes

How can the induced voltage be proportional to the frequency?

The current through the magnetizing inductance is reduced proportional to frequency so it cancels out. Faraday’s law works both ways. Since the magnetic field density in the core cross section is ...
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2 votes

How to hook up a transformer to 120V AC?

You can use either of the black wires for neutral and hot. You should connect the earth wire. The transformer is Class 2 but is not an impedance protected type, so it contains a thermal fuse or ...
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5 votes

How to hook up a transformer to 120V AC?

Connect hot (usually black) of your cable to one primary (black) lead of the transformer. Connect neutral (usually white) of your cable to the other primary (black) lead of the transformer. Connect ...
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0 votes
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Homework: impedance equivalence with transformer

It looks correct, but let me solve and see if I get the same.... $${V_{1}=6V_{2}}$$ $${6I_{1}=I_{2}}$$ Assuming that voltage rises are positive and voltage falls are negative... $${10\angle0-V_{1}-6({...
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2 votes

Determining the characteristics of an unidentifiable low-frequency transformer

It sounds like you already have the windings identified. For other readers I'll give a tip. When measuring an unidentified transformer, always apply your excitation to the highest resistance winding. ...
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  • 140k
0 votes

What type of power supply is best for short circuit experiments?

You could use a constant-current power supply. These give constant current at a variable voltage. But the most useful aspect of them is they are inherently current limited - they cannot give more ...
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2 votes

What type of power supply is best for short circuit experiments?

There are a wide range of "bench" power supplies, used for developing electrical and electronic products. A basic one might have an adjustable output voltage, perhaps 0 to 30V, and an ...
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0 votes

Does skin effect increase the eddy current losses inside magnetic core?

The confusion arises from a category error, I think -- skin effect is core loss! If there were no skin effect, we would know that the conductivity of the core is zero, and thus core loss is zero. For ...
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3 votes
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Linear Power Supply - Overload Protection Circuit

I would like to understand in detail how the "OVER-LOAD PROTECTION" really works ... Simulated that "thing", EE&O in the schematic ... Some names BJT transistors changed, don'...
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  • 3,603
2 votes

cw and ccw transformer secondary

If you passed a current through a secondary which consisted of two half windings in either anti-series or anti-parallel, then the magnetic fields due to the currents would cancel out to zero. You have ...
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1 vote

Why is there a copper winding isolated from the iron core of my transformer?

Seems to be a choke (acts as flywheel to smooth rotation). I think the (giant) rectifier diodes have been cut out? Is that for AC or DC welding operation? Looks like AC without the rectifier but not ...
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-6 votes

How does a transformer transmit power from the primary to the secondary?

Let us first repeat the question 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 ...
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1 vote

How to properly wind a high frequency / high voltage transformer?

I've tried for a pretty long time to do PWM on transformers, and the best you can do is shoot to avoid transformer saturation. The first thing I noticed about your circuit is that there are no ...
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3 votes

How does this PNP transistor improve the switching performance of MOSFET?

The transformer load will never be sufficient to reset the primary coil even with R1 set to a 100 ohm value. R1 is redundant when the gate diode and PNP conduct the forward and negative voltage pulse. ...
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3 votes

How does this PNP transistor improve the switching performance of MOSFET?

The other answers have covered the meat of the questions, however there is one more aspect to call attention to: the right circuit needs a resistor between transformer and base. As shown, the C-B ...
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0 votes

How does this PNP transistor improve the switching performance of MOSFET?

To switch the FET on, its gate capacitance must be charged and to switch it off, that capacitance must be discharged. Fig. 2.6 This uses series resistor R2 to limit the current drawn from the ...
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0 votes

Typical impedance values for a large 150 MVA power transformer

Short circuit impedance of real transformers (220 kV, 66 kV and 30.8 kV) I can look in my company are between 3% and 8%, 4% is the most common value.
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0 votes

How to protect home from the main connection line short circuit?

Things one can try to fix an often breaking utility power: Apply political and/or judicial pressure over the utility provider to fix their grid - slow and maybe hard, but efficient in terms of effort ...
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