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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Toroidal transformer

I have a toroidal transformer ac 230v with x2 25v. I am trying to power an old ham amplifier witch takes 28v 8amp (transistor) (blw77). I have now linked the transformer to an 8 amp bridge ...
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29 views

Question about transformer current

I got Step down transformer which reduces voltage from 230 VAC to 40 VAC ~ 100 amp. I can weld with it while having no problems. Also I got another one step down transformer which is three phase, but ...
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25 views

Replacing speakers' transformer [duplicate]

I have recently purchases new speakers and I have noticed a slight hum coming from the transformer, therefore I am considering replacing it. The transformer, used to power an internal amplifier, ...
2
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2answers
77 views

Transformer Inductance not taken into account?

When modeling an ideal transformer, why do we not consider the inductance of the primary and secondary winding of the transformer. Wouldn't this inductance affect the current pulled from the source? ...
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4answers
107 views

earth as a voltage reference

Why is the neutral point of the alternator hooked up to the earth which makes all the voltages of the lines with reference to the earth. Doesn't this makes us more risky to the shocks? I think we use ...
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41 views

Step up transformation for popcorn-maker [on hold]

My brother bought me a Presto Hot Air Popper machine from Amazon and got it shipped over to me in Malaysia. Lovely gift, he meant for roasting coffee beans actually, for which it apparently works ...
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19 views

The reflected impedance from secondary muti-windings

If a transformer with only one secondary winding, the reflected impedance from the secondary winding is $$ Z_{p,eff}=(\frac{N_{p}}{N_{s}})^{2} \times Z_{s} $$ This is a well known equation. But what ...
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2answers
67 views

Does transformer humming cause notable waste of energy?

AFAIK transformers hum because alternating magnetic field causes pieces of laminated core to slightly deform and vibrate and that is simply a byprocess of how transformers work. However for the same ...
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25 views

Capacitor and resistor in parallel to transformer secondary and bridge rectifier

I have more or less of a reference design at hand (only hardware, no schematic) where a 6k8 resistor in a 2512 package (imperial) and a MLCC are placed in parallel to the transformer secondary before ...
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55 views

Reason and mathematical explanation for 180 phase difference between input voltage and voltage across inductive coil

In an ideal transformer,why is the input voltage (say Vp) is 180 degree out of phase with the voltage across the primary coil (say Ep)?Vp leads Ip by 90 (according to many diagrams found on the ...
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14 views

How to calculate the mutual inductance

I would to know how to calculate the mutual inductance between the primary and the secondar coils of a stacked transformer which are separated with 'd' distance..
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26 views

Why is E_1 negative in an exact transformer equivalent circuit?

My electrical engineering professor has written the primary EMF with a negative sign in the transformer equivalent circuit: He has also written this equation relating to the circuit: ...
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1answer
52 views

How will I get the per-unit parameters when the data from the short-circuit test are shady?

Data from short-circuit and open-circuit tests of a 60-Hz, 100-kVA, 4600–230-V transformer are: VOC = 230 V IOC = 14 A POC = 60 W VSC = 172.3 V ISC = 20.2 A PSC = 1046 W Get ...
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1answer
48 views

Why do Flyback Transformers have C-I cores?

Usual transformer cores are either E-I or E-E. What's the reason for Flyback's being only C-I? Does it simply cut the cost?? I want to know if it would perform less if it were an E-I.
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28 views

Mutually Coupled Inductors

Hello there im working on a project in which i'm making a wireless mobile charger. Im using two mutually inductors for transferring power wirelessly i want to transfer 14V (AC) from my primary coil to ...
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1answer
44 views

Using a multi tap transformer

I'm new to electronics I have need some help with a power supply design I am designing. I currently have a 0-30 volt, 2 amp multi tap transformer that I am using for the above mentioned power supply ...
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0answers
20 views

Multiple Oscilloscope measurement in Multisim with small Variance

I have a design that consists of several stages, it's Dual DC Regulated DC power supply, using transformer, bridge rectifier, capacitor filter and regulator. We add the components one by one and each ...
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0answers
26 views

How ybus will change in Newton-Raphson load flow when we place three phase transformer in three phase load flow [closed]

I am doing a project on calculation of three phase load flow by using the Newton-Raphson method. I wrote a program for that and now I want to place a three phase transformer in a line. Finally, I ...
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3answers
105 views

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

I'm trying to get my head wrapped around transformer operation and in the process regretting the times I snoozed in my Electromagnetics class as a EE student back when I was a lad :) I'm looking for ...
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1answer
35 views

Connection of two identical transformers

I have a substation with two identical transformers 110kv/25kv single phase 50 hz usually one acts as spare. Now for some reason i want to charge my substation from secondary side i.e., 25 kv side ...
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2answers
272 views

Help me understand this load detecting circuit

I'm looking at this circuit: Which has come from here The claim is made that "it detects a voltage drop across a large bridge rectifier that acts as a high power shunt", which is referring to the ...
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0answers
15 views

Need Suggestions in winding 2x80vac 12amp Transformer

I want build 2x80vac 12amp Transformer for power amplifier ,i am confuse in calculating the wire gauge AWG for primary and secondary winding ..... need suggestions
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1answer
54 views

Boost converter for PV

So my two PV panels giving me an output of 40v, 1.5A. I am sensing both current and voltage of the PV output to give an MPPT duty cycle pulse. I want to boost the 40VDC to at least 400VDC and ...
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37 views

What parameters are key in selecting a transformer to pass digital data?

Looking to fiddle around with some digital signaling through transformers. Never done, so this is just to experiment and see what it looks like. For the purpose of digital isolation, what types of ...
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1answer
41 views

Spiral Core Transformer

Presently, I am reading about different types of transformer. I am stuck on 'spiral core or wound core transformer'. I didn't find any good explanation about it in the textbook I am reading. Searched ...
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2answers
40 views

Why is HV kept open in OC test of transformer?

Why is HV kept open in OC test of transformer? Also, why is LV shorted in SC test of the transformer? (Generally this is preferred - why?)
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1answer
24 views

Open circuit test on rated voltage

In transformer, the open circuit test is performed at rated voltage and frequency. why so? How both of these factors i.e voltage and frequency affects the transformer working?
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1answer
89 views

Microwave Oven: Switching Magnetron (Transformer) with SSR [closed]

I've got a used microwave oven and want to improve it with a digital user interface. Is it ok to switch the magnetron (more precisely: the transformer from 230V 50Hz to some kV followed by a diode ...
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0answers
54 views

Best Way to Extend 30A 120v circuit over 300 feet? [migrated]

I have an old barn to which i'd like to provide electricity. The problem is that the barn is about 300 feet away. I understand that voltage drop over 300 feet is fairly significant. Buying thicker ...
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0answers
20 views

how to design reactance in the transformer?

how to design reactance in the windings of transformer? I have calculated it from the impedance and resistance but i am not unable to get the desired output from that value. so please can you specify ...
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2answers
62 views

Soft start… for a transformer

so I have a transformer (3kva 120vac -> 240vac) that runs great but blows the breaker occasionally on startup. So I'd like to add a soft start. This is an industrial control environment so I could ...
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3answers
63 views

Can I use a transformer to drop a DC voltage?

Can I use a transformer to drop down the voltage from a generator? Or should I just use a regulator? The generator outputs about 9.3 V and I need about 5 V, and I want to conserve power.
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2answers
58 views

Replace transformer with PWM control

This is my first question on stackexchange so if I do anything wrong, please let me know :-) So my situation is the following: I am working on a power supply module where I need 7 separated +28V DC ...
2
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1answer
68 views

Standard transformer for higher-voltage dual output flyback converter

Is it possible to modify this flyback converter to get the output voltage somewhere up in the range of +/- 26-60v (preferably 30v or more) without having to make my own transformer? I would also like ...
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2answers
55 views

Grounding a 30KVA isloation transformer

My company does audio visual services. When we use a single 120/208 VAC Three-phase "Y" power source for lighting, audio and video we get noise caused by the lighting dimmers injected into the audio ...
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1answer
70 views

what is the waveform difference between primary and secondary of transformer

I am talking about the autotransfomer. I am wondering how would the waveform be different is if I measure the Voltage at primary side, versus measuring voltage at secondary side. Is the general ...
0
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2answers
86 views

Convert 6 volts dc to 300 volts dc

I am trying to build a portable Geiger-Mueller tube that is run on 4 AA batteries. However, the tube runs on 300 volts. What is the most efficient way to do this. I have looked for transformer that ...
1
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1answer
69 views

Step up converters DC or AC?

The wikipedia article on Step up converters says A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. However if I look at ...
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2answers
63 views

Short-circuit primary side of a transformer to collect all the spikes at the secondary

Abruptly detaching a power source from a coil produces a back-emf: this is a well known fact. What I would like to achieve, in my experimentation, is to convey ALL the collapsing magnetic field to ...
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0answers
31 views

Passive harmonic filter: Why Immensely Hot and Humming

I encountered a passive harmonic filter, PHF with highly non linear loads, i.e. variable frequency drive, VFD (most of the time running 50Hz) serving an induction motor. I believe that it is a ...
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0answers
53 views

different voltage input on a transformer used as output

I have a transformer which I Take from my bridgeport milling machine panel box,I am thinking to make a phase converter and need 380v from my 220v single phase supply. this is the diagram of the ...
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0answers
30 views

How to connect a microcontroller to a magnetic coil loop?

I generated a 10MHz square wave from one output pin of a microcontroller using on and off mechanism. I want to give this as an input to the coil.I can connect the output pin to the one end of coil, ...
0
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1answer
66 views

Short circuit current in transformer

When transformer secondary is short circuited, what would be the value of current flowing through short circuited side? Shouldn't it be infinity ideally? If yes, is it only due to large cross-section ...
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2answers
165 views

How would I convert a 4.1(ish) volt li ion battery to 240v ac?

I'm fairly interested in electronics but not very educated in it. I was wondering how I would go about safely converting your average li ion battery pack to a usuable voltage (240v ac) for things ...
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0answers
45 views

Connecting an tube output transformer “wrong” to get different primary impedance

I'd like to build a tube amplifier (not for guitar), but have a problem in that it seems I cannot get an output transformer that is proper for the tube (required primary impedance and power rating), ...
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1answer
21 views

Wattmeter Required for Transfomer Characterization?

I have to characterize and test a small 6VA 230VAC Transformer. Seems like I will do 1) Winding Resistance Test - DC Test 2) Open Circuit Test 3) Short Circuit Test I do not have a wattmeter, ...
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0answers
54 views

Power adapters 5v

Today, I wired my home door bell to the mains because I had to keep replacing battery every 2 months... It required a 9v supply and I had two identical door bells. As I only had a 17v power adapter ...
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0answers
44 views

Do I need to insulate the inner box?

I am currently putting a transfotmer inside a metallic case. The transformer has to be grounded so does the metallic case. Looking inside the box, my frnd suggested that I might need to put a ...
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2answers
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Wiring a 2.5km football field with 220v

I have a football field to wire up. It measures 900m x 450m. I need to connect multiple light weight devices that use a 100-220vAc adapter that convert the voltage to 24v for the daughter device. ...
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36 views

liquid insulator by example?

can someone give me some example about liquid insulator .from some text which has been read by me it is just oil can someone told me the other one . it would be good if there is any book reference ...