All Questions
Tagged with transformer power-engineering
61 questions
2
votes
1
answer
228
views
Transformer power mismatch in Falstad Circuit Simulator, bug or true to life?
To understand how transformers function better, I created a circuit in Falstad Circuit Simulator. As you can see since the transformer has equal amount of coil windings in both sides, the current and ...
-1
votes
1
answer
87
views
Transformer Cores Datasheets - Core Loss Information
Transformer core datasheets generally have Core loss - Pv (kW/m3) versus Flux Density - B (mT) graph but some doesn't, instead it is given in a table as shown in the picture below for one of the EE ...
- 730
0
votes
0
answers
71
views
Why mutual inductance be less than or equal to geometric mean of self inductances of coils?
I understand when coils are coupled together the leakage of flux into surroundings causes mutual inductance to be less than self ones but why it has to be less than or equal to geometric mean of the ...
-1
votes
1
answer
82
views
Does the center tap of a single phase distribution transformer get bonded to the grid neutral? [duplicate]
Here are the two wiring diagram.
- 15
0
votes
2
answers
129
views
Is this how a single phase transformer is connected to multiple houses? [closed]
Single phase transformer serving 3 houses:
I am not sure if this correct. Can someone confirm?
- 15
1
vote
2
answers
229
views
What information can be discerned about street-side power transformers just by looking at them?
I am new, and delighted, to be part of this stack.
I was just wondering from the two images of power transformers shown below what specifications can be gleaned from their outward appearance alone?
...
- 121
12
votes
3
answers
1k
views
What are these circular basket-like structures on a high voltage transformer's insulators?
Wikimedia commons contains this public-domain image of a high-voltage transformer of the Tarza power plant in Iraq, taken by Marvin Daniels in the U.S. Army:
There is much I do not immediately ...
- 655
0
votes
0
answers
171
views
For Delta-Wye transformers, with neither side grounded, can one get electrocuted by standing on earth and touching one of the Delta side wires?
It seems to me that there is no path to ground in this case. So, the voltage on the Delta-side of the transformer cannot drive a current through the ground (ie, through the one touching the wire), ...
2
votes
4
answers
184
views
The voltage created in the transformer
The voltage generated in the transformer must be due to the change in the flux in the coils, but if the voltage is DC, why is no voltage induced?
Of course, we know that voltage is created by the ...
- 145
4
votes
4
answers
1k
views
How many winding turns in a HV power transformer?
I'm creating a simplified 2D model of 3 three-winding 132/22 kV, 40 MVA transformers that I'll use to calculate the magnetic field surrounding them.
Now, the turn ratio is of course 132/22, but is ...
- 1,619
1
vote
2
answers
596
views
Duty cycle in flyback transformers
I have a small doubt. If the flyback transformer is designed to vary duty cycle from 5-50% and obtains an output voltage of 5 to 100 V. Here, can we increase the duty cycle beyond 50% (70-80%) as to ...
- 37
1
vote
2
answers
399
views
How do I connect a three phase transformer with three center taps?
I have a three phase step down transformer with three center taps like shown below:
How can I connect it to get the 90 V three phase lines or the 45 V three phase lines at a time for circuits that ...
- 366
0
votes
2
answers
3k
views
What is the difference between applied voltage and induced voltage at primary side of transformer specifically?
I am not able to understand difference between applied voltage and induced voltage. Whenever voltage is applied at primary side of transformer there will be primary current producing flux using ...
- 1
0
votes
1
answer
908
views
How power system handle unbalanced load?
how a delta connected primary winding of three phase distribution transformer tackle unbalanced load of three phase 4 wire unbalanced load(unbalanced load is quite common due to supply of single ...
- 31
0
votes
0
answers
70
views
Transformer load
I have 50 kVA delta-wye transformer with 3 single phases secondary (line-neutral) delivered to 3 houses, So if one of the 3 houses drown more power would that affect another 2 houses, or each phase ...
0
votes
1
answer
419
views
2 simultaneous voltages from a transformer
I need a step down transformer that can give me 2 voltages simultaneously.
Primary will be 380vac and secondaries will need to be 24 vac and 12 vac. Instead of using 2 transformers, I would like to ...
- 13
3
votes
2
answers
605
views
Delta-Wye transformer differential protection during external line to line faults [closed]
During these kind of line to line faults current flows in the faulted phases of the secondary and all phases of the primary as it is shown in the image. So now the currents in phase A are not equal to ...
- 63
1
vote
1
answer
788
views
What cause sudden spike in the output voltage of transformer?
What issues can cause the output voltage of a transformer to suddenly increase from 230 volts to 400 volts (in the case of any transformer and in the case of the delta to Y configuration of the ...
- 33
0
votes
2
answers
583
views
Need help to understand inductor based non-isolated offline buck converter [closed]
Here ADGJ IC is used in offline buck topology.
Can anyone share the schematic of it.
Picture taken from sonoff mini and shelly1 board is attached below
- 331
-1
votes
1
answer
167
views
Transformer cooling difference between water cooling and air cooling [closed]
I just know air cooling method is cheaper than water cooling method. Please tell me what is the difference between air cooling and water cooling? And if you could please use some pictures to explain ...
- 1
0
votes
1
answer
124
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. ...
- 558
2
votes
2
answers
2k
views
What is the air gap area?
I found in a book the air gap area is \$Ag= (W+l_g)*(d+l_g)\$ However, I know therectangular prism is \$A=2*(w*d+d*lg+w*lg)\$. Could any one please help me what they have air gap equals \$Ag= (W+l_g)...
- 21
1
vote
1
answer
852
views
How can I compute the power flow for a network with transformers (as in the WECC 9 network)?
I'm trying to solve the power flow for the WECC-9 bus reported below:
all generators (1,2 and 3) are behind a transformer, which has a Voltage converter ratio (e.g. 18/230) and a reactance(?), which ...
- 59
1
vote
0
answers
57
views
How is voltage induced in Yd transformer without neutral connection sinusoidal?
Thia is regarding bank of 3 single-phase transformers having star connected primary with isolated neutral and delta connected secondary.
I know that for bank of 3 single phase transformer core flux ...
- 602
0
votes
2
answers
1k
views
Stacking M.O.T. to create an E-E core
I just came across this site looking for answers on some questions I have concerning microwave oven transformers (M.O.T.). I am currently going into my third year as an E.E. student and I am trying to ...
0
votes
0
answers
463
views
How to have Wye-connected Potential Transformers(PTs) and Neutral Ground Resistor short circuit detection at my ground fault protection relay?
Detecting if the Neutral Ground Resistor (NGR) is shorted is something that must be checked at the Ground Fault Protecting Relay. The typical way to do this is to inject a DC component and to measure ...
- 399
2
votes
0
answers
274
views
Startup and auxiliary/station transformer power parallel to bus
This question is in regard to switchyard/electrical distribution operations in a utility power plant.
During a startup, the electric distribution system is lined up so that the startup transformers ...
0
votes
1
answer
46
views
What is the effect of very small AC frequency deviations from the grid on invertors and transformers for normal comsumer objects?
What additional wear or inefficiencies are there from inverting a AC signal to DC from say, 59.99 hertz instead of 60.00 hertz? And is there additional wear on transformers? How do small deviations ...
- 101
0
votes
1
answer
985
views
How to plot input reflection coefficient in dB scale using Matlab
So I have a problem that asks to plot the input reflection coefficient of a transformer in dB scale between 0.5 GHz and 4 GHz using Matlab. Here is the code I have thus far, it is plotting in ...
user165397
2
votes
1
answer
302
views
How is power out one side of 220 only - Problem is with incoming 3-phase. But how?
[EDIT] Can someone who understands what I wrote explain this?
[EDIT 2] Sorry I didn't say I'm in the USA, the power is 110/220vac 60Hz. The input to the main power transformer is 3-phase, underground,...
- 121
1
vote
0
answers
449
views
Use of 3 phase transformers which are ∆-Y connected and Y-∆ connected
Different literatures say different things regarding ∆-Y and Y-∆ 3 phase transformer connection...
Some say that ∆-Y is used for step down and Y-∆ is used for step up while others say just the ...
- 155
2
votes
2
answers
2k
views
Why is a short circuit in the secondary winding of a transformer reflected on the primary side?
I was reading this answer and I would like to understand why if the secondary is short circuited the primary winding will also reflect the short circuit despite the fact that they are isolated. Would ...
- 399
2
votes
2
answers
130
views
Regarding Power Market demand and supply
As I have read, that power supply should be equal to demand. As it can't be stored .So basically this means power is generated in real time.
Consider an area where power comes from a Substation A, ...
- 123
0
votes
3
answers
3k
views
Process for Making a Flyback Transformer
I am looking to make my own flyback transformer that can put out a DC voltage from 0 to -40 kV DC and a power of 400 watts, as most commercial flybacks do not go up to the specified power and ...
- 133
0
votes
2
answers
112
views
What are the methods to measure distribution transformer vibration in 0.5g range?
It may seem obvious to use widely available analog devices MEME accelerometer for measurement in range of 0.5g. I did thorough study on this and found out that MEMS sensors either doesn't work or ...
- 286
0
votes
1
answer
240
views
Pass power to components on a high speed spinning motor
I have a small Emax RS2205 2600kv 16v DC Motor that is turning a PCB with IC chips that needs to be powered.
I want to send 2 power cable (VCC and GND) from to stationary battery to the rotating PCB.
...
- 15
7
votes
1
answer
460
views
How practical would it be to field rewind a large power transformer that's suffered damage from a geomagnetic storm?
It is commonly accepted in power distribution circles that large (large substation-sized or larger -- smaller substation-class transformers are much more readily replaceable) distribution transformers ...
- 9,018
-1
votes
2
answers
95
views
In this current therapy circuit design how to reduce output current [closed]
Here, I plan to switching two N-type MOSFET by using 12 V step up center tap transformer (1:10). My output is around 120 Vac. Its great but the current is nearly 17.5 A. How can I reduce the current ...
- 1
-1
votes
2
answers
730
views
Generation of power using multiple step up transformers
Why do we need huge generators to produce electricity? Is it not possible to use a small generator to produce a small voltage and then use multiple transformers to step it up?
- 1
2
votes
3
answers
816
views
Isolation provided by transformers
I have a few questions about transformers and isolation. I will describe my understanding (maybe wrong) and questions about them.
Transformers provide safe isolation by disconnecting two circuits ...
- 4,440
1
vote
0
answers
202
views
Determining VA rating of the small transformers
I have a 1000VA toroid transformer which weighs 8 Kg. Based on this power-to-weight ratio, can I conclude that another transformer which is EI cored and weighs 7 Kg must be 875VA? Or such ratiometrics ...
- 1,705
0
votes
1
answer
106
views
Low weight split core transformer on 11kVA transmission line
I've seen transmission line energy harvester's that utilise a split core transformer. Here is an example.
However, I fail to see how this is possible when a transformer cores which are small enough ...
- 115
2
votes
2
answers
441
views
Can an audio receiver with a 130v-rated switching power supply be modified to be used without a power transformer?
I have a Harman Kardon AVR, imported from the US, which uses an SMPS (130v) that I will use in Asia. Is there a way to modify the component inside the Power supply so that I can use it without a bulky,...
- 21
3
votes
8
answers
19k
views
Why do we need to install a power transformer for each high building?
I live in area where many high buildings are being built. Each building is more than 10 floors. A special room is made next to the main entrance or the garage. The room is designed for installing a ...
- 3,854
0
votes
1
answer
109
views
Appox. the Impedance of Single Phase Pole Transformers using only Nameplate Ratings?
I know the following of one pole transformer (don't have access to the nameplate):
333KVA, Z = 5.75 % 25kV/12kV
Given another transformer, I don't know Z, but know it's rating and voltage
...
- 143
1
vote
1
answer
62
views
Why am I getting different Voltage Losses?
The step-down transformer has a ratio of 10:1
$$P_{globe}=V_{globe}\cdot I_{globe}$$
$$P_{globe}=V_{globe}\cdot I_{globe}=\left( 2 \right)\cdot I_{globe}=4\ \mbox{W}$$
$$I_{globe}=2\; \mbox{A}\; ∴\; ...
- 113
0
votes
1
answer
1k
views
On load tap changer controller switching
A 20/25 MVA transformer has an On load tap changer (oltc). Here a HMK7 Controller is used to control the motor drive of oltc. Which seems like
There are two buttons 1-N & N-1. Red seven segments ...
- 126
3
votes
1
answer
13k
views
What is the zero-sequence equivalent of a YNy0 transformer?
The zero sequence equivalent network of a YNy0 transformer with grounded primary is shown below (source).
It looks like there is no connection between the primary and secondary side of the ...
- 1,619
0
votes
3
answers
92
views
Given thermal capability of a transformer, how to best estimate the voltage regulation?
I'm working with a system that has 3 2MVA transformers for which there is an existing estimate of the peak load and the power factor. The xfmrs appear to have a greater thermal capability than the ...
- 21
17
votes
4
answers
87k
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, ...
- 3,854