Questions tagged [transformer]

A transformer couples two or more AC signals through a magnetic field. Often used as galvanic isolation and to transform one AC voltage to another.

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3answers
67 views

What if everyone uses voltage stabilizers?

A hypothetical question to improve my understanding of stabilizers and power supply. Consider a rural village where frequent low voltage issue happens. Now, if everyone there uses stabilizers to ...
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1answer
64 views

Is it common practice to use transformers rated 50% over the load you want to use?

I designed a flyback power converter circuit with a transformer rated for 25 Watts, I expect to use all 25 Watts, could I use a transformer rated for 35 watts in this application? Is this typically ...
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198 views

Power Supply Transformer with 3rd Wire on Primary

I'm sitting here with a $600 espresso machine with its power transformer not working (no voltage coming out of secondary, with 110V feeding the primary). I've been scouring the internet for a ...
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1answer
32 views

Calculation of switching transformer at 100kHz

I am not able to desgin transformer for switching frequency 100kHz. It´s easy to desgin usual transformer for 50 Hz. But I´m totaly out when comes to switching transformers. What material should I use?...
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1answer
29 views

Characterising an Audio Isolation Transformer

Rummaging around the junkbox in an effort to find a 600:600 ohm audio isolation transformer, I found a possible candidate rescued from a store closure some time back. It's basically a cheap, low ...
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1answer
23 views

If two identical transformers are connected in parallel, referring to LV(secondary) side, any change?

Assume transformers are 10/0.4 kV 500kVA transformers. Primary is high voltage side and secondary is the low voltage side. ...
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0answers
11 views

Modelling internal fault in a transformer

I am doing an analysis of faults in transformers and i need to model internal faults in a transformer. Please do advise on how to model internal fault in Simulink. Thanks in advance
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1answer
197 views

Why are tapped transformers needed in RF amplifier circuits?

I'm not really sure why, but I have seen many different RF circuits in which the input to a transistor is taken from a center tap instead of across the entire secondary, such as this example: Why is ...
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2answers
237 views

NE555 Controlled Transformer Voltage Spikes

I am attempting to build a NE555 timer controlled step up transformer (3:250). R2 and R3 will be variable resistors when it is completed. Input is 12V and I'm stepping that up to about 1000V. The ...
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1answer
41 views

Altium->Coupled Inductors

Im glad to be with you. I have question about coupled inductors in altium. I want to make a flyback converter and tried first as in Image 1 . I converted 310V DC to 12V DC as you can see. I wrote ...
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1answer
201 views

Connecting the secondary side of ignition coil to earth

I have an ignition system used for some application. During the testing I found that spark plug is producing EMI due to spark occurrence and high voltage is traveling through the wire. So to ...
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0answers
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How to step down 50kv to 300v (dc/dc) [closed]

I am thinking about stepping down 50kV DC to 300V DC - is it possible? 50kV dc 0.001 A Is there step down transformer with this voltage? I am ok with expensive solutions, but does zener diode help? ...
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3answers
103 views

Why can't I get transformer output as written on the label?

TLDR: I've made a short video about this, if you like looking at a video more than reading this. It's here: https://youtu.be/51235iFywI4 The problem is pretty straighforward. I have a (toroidal) ...
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3answers
1k views

How critical is winding a solenoid/electromagnet neatly?

We've all seen the expensive toroidal winding machines on YouTube, and manufactured solenoids are always so neat in construction - as in: Each winding is neatly packed to its previous, without ...
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0answers
42 views

How to convert 220V AC to 12V 500mA DC safely? [closed]

I want to make a converter that converts 220V AC to 12V DC. I have a water pump that pumps water out from a small fish tank. Which is rated 12V 8W. Can you help me with a circuit diagram? It will be ...
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2answers
163 views

How does this old fan regulator circuit work?

I was looking for an old fan regulator for a long timebecause a lot of people said that the power consumption of it was the same at high speed and low speed. This is a 50 year old fan regulator (...
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0answers
25 views

How do transformer winding strategies affect stray capacitance

I have a project that involves handwinding some rather compact transformers (toroidal cores about 0.5cm outer diameter; max number of turns on one coil of about 150), for which I am interested in ...
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4answers
6k views

Car subwoofer powered by mains voltage

I have a car active subwoofer, 550w RMS, 1600w peak, which I would like to use in my home, and power it from 220v mains. ~133A is a fairly large ask from a transformer, I think, and even 46A seems ...
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1answer
47 views

Power In= Power Out in transformers

In transformers, we prove that the induced voltage per turn is the same in both primary and the secondary coils of the transformers, i:e (Ep/Np)=(Es/Ns). But when it comes to currents, we show that (...
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1answer
259 views

Interleaving in litz wire transformer - to be or not to be?

i am designing a transformer for 2-switch forward converter. For now, primary is wound as 5 wires of 0,5mm diameter (34 turns, 3 layers), the secondary is wound as 3 wires of 1,32mm diameter (17 turns,...
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1answer
97 views

Transformer vs. switched-mode power supply

I'm working on making my own bench power supply, I want up to 7-8 amps. The switched mode power supplies are much cheaper than the transformers. Why would one choose a transformer instead of switched ...
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2answers
36 views

Power recirculation rig using rectifiers and BLDC motors

I am currently trying to set up a rig to test my 3d printed gears under different torques and motor speeds. The power input side is going to be the BLDC motor, driven by a hobby ESC (BLHeli_32), ...
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1answer
21 views

Can you argue the current decrease along the two inductor pieces of a transformer using impedance?

I'm looking for a way to explain it other than using energy conservation/ power equal logic. in this we derive the relation between current in each coil by equating powers and then using the ratio ...
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1answer
33 views

Buck-Boost Transformer with Three Phase Wiring

I live in a residence with 120v / 208v electrical service. (Measured as leg1: 124v, leg2: 125v, 215v across legs) I am nearly certain that the service is the result of two legs of three phase power. ...
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3answers
68 views

How can current be in different phases in the same wire at the same time?

We know that either in ideal or practical transformer in no-load condition, the exciting current has two components Ic(core loss component) and Im(magnetizing component). Now since the same current ...
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1answer
50 views

Fuse on Primary Side of Transformer keeps blowing

I have a HVAC which is having a 24V 40VAC transformer. I might have shorted the output of the transformer while working on the wires. I noticed that the fuses on the input side of transformer blew ...
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1answer
62 views

It is possible to use a 100W 12V solar panel directly to charge a laptop, using a buck converter for example?

I am planning to go off the grid due to the pandemia, to an isolated village. I am working remotely I am looking for a solar approach to power my laptop ACER A5 515. The charger is rated 40W. I was ...
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2answers
6k views

Is there any Phase difference between the current in primary and secondary coils of a transformer?

Is there any Phase difference between the current in primary and secondary coils of a transformer? If I draw the diagram of a transformer, and try to find-out the direction of current using Lenz's ...
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1answer
170 views

Flyback converter primary and secondary sides power calculation

The problem is as below. Input DC voltage is at 12V, transformer inductances are: Lp = 60uH, Ls = 240uH, switching behaviour is controlled by a single NMOS with switching frequency at 60kHz. For ...
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4answers
199 views

Question about ideal transformers and inductors

Recently I was studying about alternating currents and transformers and I got confused about some of the concepts. I tried a lot of sources but none of them seemed to address the problem. I ...
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2answers
57 views

how to transform 120V AC to 5V DC 5A load using flyback transformer circuit? Setting frequency - low cost, low footprint - change load capacity

i am using a flyback transformer circuit to keep the footprint small and cost efficient. Its been suggested to me to keep the frequency high so the transformer can remain small. how is the frequency ...
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5answers
15k views

Confusion about dot convention in an ideal transformer

I am confused about voltage polarity and current direction in transformers , for example the equivalent circuit of the ideal transformer in figure(a) the instantaneous voltage polarity of the ...
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3answers
2k views

Is it safe to plug a transformer into a surge protector?

All my searches have come up with "DO NOT PLUG A SURGE PROTECTOR INTO A TRANSFORMER," but what I need to know is the opposite (if I can plug a transformer into a surge protector without issue). What ...
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1answer
56 views

Why will we get the wrong answer if we use \$I_1=\frac{V_1}{Z_1}\$ to calculate \$I_1\$ directly?

There is a transformer with \$600V/120V\$, and the impedance in the high voltage side is \$52-30j Ω\$, and there is a loading, which impedance is \$0.8∠10°Ω\$, connected with the low voltage side. ...
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2answers
494 views

What does an Impedance of a transformer mean?

If Impedance is given as following, Center Frequency : 455KHz Pri = 60KOhm Sec = 600Ohm Inductance = 680uH Tuning Capacitane = 180pF + 5pF(ext.) What do they mean? Do they mean impedance at ...
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2answers
54 views

Transformer vs SMPS for bench supply

One of the basic circuit to step down input voltage is to use a buck converter topology. Some power supplies reduce input voltage using non isolated type while others use isolated type (example use ...
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0answers
28 views

Clearance requirements from EGND to SGND on ethernet transformer

I have previously been instructed to have a ~70mil clearance between DGND and EGND and to bridge using a 1.5kV 0.47u cap. Application notes also show a 2kV 1000pF cap to EGND off of the center tap ...
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1answer
68 views

High open-circuit voltage in isolated push-pull SMPS?

I'm developing an isolated push-pull SMPS. I am attempting to transfer power through a custom center-tapped (on both primary and secondary side) transformer, stepping down from 20 V to 4 V. I am ...
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4answers
53k views

Why does a delta/wye transformer make 30 degrees phase shift ?

I'v heard that a delta/delta or Wye/Wye transformers do not make any phase shift. In delta/wye or wye/delta transformers, There is a 30 degrees phase shift between the primary and secondary coils. So, ...
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2answers
74 views

Is there any disadvantage with transmitting the same excitation signal to several resolvers (basically rotating transformers)?

I am considering sending the same excitation signal to multiple resolvers (i.e. transformers of which the secondary rotates with respect to the primary) used as angle sensors in the joints of a ...
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2answers
142 views

Transformer windings order

I have several transformers for audio amps, with single thiner primary and dual larger area secondary windings, for lower voltage higher current. They are toroidal, all by different manufacturers, but ...
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0answers
26 views

Reduce 50 Hz noise from robot-mower charger

I just bought a robot-lawnmower (Husqvarna Automower 105), which is working perfectly. But the charging station is making a loud 50 Hz noise all the time, even without the robot charging. I have ...
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1answer
24 views

Skin/Proxmity effects near transformer core

The above picture shows a rectangular wire carrying alternating current wound across a core with permeability much much greater than of free space(and also assumed is the fact that the width of the ...
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2answers
56 views

Full wave center tapped transformer output voltage

I have a full wave center tapped transformer circuit with input voltage of 220V How do I get an output voltage of 15V. What equations should I use ? Here is the circuit:
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22 views

Troubleshooting adding a bluetooth receiver to my intercom system

I have a Nutone IMA 4406 intercom system with several intercoms throughout the house. I am interested in wiring a Bluetooth receiver to its Auxillary line in connection so that I can stream music ...
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0answers
33 views

How to calculate the current through load resistance in the given diagram?

I am here with yet another problem, where I have to find load current, ripple voltage, approx turns ratio? Also, any idea about how can we reduce ripple voltage further? Attempt: This is a step-down ...
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1answer
138 views

High Voltage Planar Transformers

I am designing a high voltage DC/DC converter that is for an aerospace application and therefore I am focusing on reducing the size and weight, so switching at a high frequency possibly integrating ...
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1answer
45 views

Voltage Divider or Step-down transformer for voltage sensing 240V AC [duplicate]

Hello I am trying to measure 240v mains AC as safely as possible. There seems to be 2 ways to do it, which of the two is better and preferred? 1. Voltage divider directly from the mains I have found ...
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2answers
62 views

Transformer Secondary Discontinuity

I am using a step up transformer and I am getting a weird discontinuity in the secondary output. Has anyone seen anything like this before? I cant figure out what might cause this. In a one test setup ...
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3answers
649 views

Questions about voltage drop at the transformer secondary and primary due to loading

Below there is an impedance matching aimed step-down transformer circuit where the primary to secondary turn ratio N1/N2=10. To actualize such turn ratio and voltage ratio, I set the inductor ratio L1/...

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