# Questions tagged [winding]

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### implementing dot convention

in the following topology, a boost inductor with secondary winding is operated in which the windings are in opposite directions. Implementing this structure, in reality, made me confused. Based on my ...
• 577
1 vote
62 views

### 3-phase motor winding heater using DC current

The motor in use is a 3-phase 440V/37kW induction motor. I have received data regarding winding heaters from a motor manufacturer. If the rated voltage is 440V, a single-phase voltage of 24Vac must be ...
43 views

### Why isn't wave winding a DC generator like shorting two voltage sources of different potentials?

Say each conductor moving in a magnetic field produces EMF $e$. In the below setup, the first parallel branch has 5 coils (5,9,4,8,3) and second branch has 4 coils (1,6,2,7.) This means, at a ...
• 1,070
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### Does this motor ever run?

I've been studying lap winding in dc motor and the geometry is quite interesting. I stumbled on below arrangement of coils for a 4 pole 4 slot double layer simplex lap winding. My thoughts: This ...
• 1,070
59 views

### DC motor, disadvantage of having independent coils

My knowledge in electrical motors is not that good. In first pic, when the coil is vertical, torque is $0$, but inertia keeps it spinning counterclockwise. I get this. With only one coil, the ...
• 1,070
1 vote
51 views

### Is there any effect on efficiency of electromagnet if winding wire cross each other during winding?

While winding a core of the transformer some turns cross other turns. Will this affect the magnetization produced by the core?
1 vote
103 views

### Rogue winding on flyback transformer?

I was reverse engineering a battery charger (Lidl brand Parkside 20V battery charger PLGS 2012 A1, with smart functions, among them charge current and termination voltage settings) and came across ...
• 775
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### How is current distributed in the cross-section of a wire? Skin effect for motor windings?

The startup h3x is claiming to have designed 3d printed coils and other innovations increasing the power density of electric motors by a factor of 3. https://www.h3x.tech/#amcoils They mention fill ...
• 1,599
1 vote
96 views

### Measuring turn ratio of a transformer

I've taken out a beafy transformer with 8 leads from PCB of a multimedia device of some sort. (Possibly a TV). 2 leads are obviously the primary coil (thicker leads and wires) the rest are almost same ...
243 views

### Why so much space around these toroid windings?

I have recently noticed some toroids wound with what I consider to be huge space left over, and I am asking if there is any good reason to do this. (or even an acceptable reason would do). My thoughts ...
• 1,956
1 vote
171 views

### Determining an industrial electromagnet coil's number of turns and wire diameter, etc

I'm a new graduate and fresh hired Electrical Engineer who works in a company building magnetic separators for general industry (including mining, recycling etc.) Normally, we build magnetic ...
189 views

### How frequency-dependent is an air inductance?

For a winding on a magnetic material, the value of the inductance is greatly impacted and is also frequency-dependent given the behavior of the magnetic material according to frequency. My question is,...
• 309
71 views

### Is there any good way to limit primary current on a low inductance transformer?

For a while, I used hand wind transformers to make high voltage (250v, then several stages of cockroft walton to 750-1000v) from ~12-24v at around 10khz and max 100ma on the primary side. But of ...
71 views

### Transformer Winding Resistance

I have a SMPS transformer and a LCR meter. I can measure 3 different resistance on a winding: R on a certain frequency(10kHz): 0.065R Rs: 0.086(I don't know what is this) DCR: 0.06 Which one is the ...
• 129
423 views

### How to limit current for a transformer?

So I've been winding and unwinding, all to get the current right but it's not going well, so I'd like to know how I can limit the current going into the primary side of my transformer, since the ...
• 128
91 views

### Number of windings keeping constant the poles

What happens if I increase the number of windings around the poles keeping constant the number of poles in a motor? for sure the rotational speed should be the same, I think that we will obtain a more ...
1 vote
39 views

### In a transformer, how do you determine where the induced EMFs (E) and voltages (V) are placed in a vector diagram?

I will be citing pictures from Electrical Technology by Theraja. So there are different cases with regards to the transformer depending on what losses and loads are considered. Each of them have ...
• 429
1 vote
78 views

### Why does an additional primary current exist in a loaded transformer?

I think this has something to do with Faraday's Law but like, I don't get why having a secondary current produces a antiphase secondary current at the same instant. Not all currents produce a direct ...
• 429
55 views

### Building a pseudo-solenoid electromagnet - Heat disipation

I am planning to build an electromagnet as shown in the picture below. The copper windings are coiled around a thin plastic cylinder. The goal of the setup is to attract small metal chips floating in ...
• 105
155 views

### Current transformer energy harvesting from a mid-voltage line

I'm planning on harvesting energy from a 33kV line which has an average 10rms A current. The main conductor (N1) has a overall diameter of about 13mm.In the beginning I tried to harvest around 3-4 W ...
201 views

### Behaviour of flux in DC motor

In given figure if we assume both sides (up and down) with equal number of coil turns (N each). And we wound(which generally we do in DC motor) coils such that they create flux and form a North-South ...
• 1,124
282 views

### Reducing equivalent self inductance of an inductor

Let's say I have a coil of N turns and it is wound on a rectangular core and when we connect a voltage source through both terminal of coil flux is generated in core , now I wanted to reduce that flux ...
• 1,124
119 views

### Inductor design

I really need your help on this. I am designing an inductor which is rated for 50 A and 350 Vrms for 85 kHz. I want to get 3 inductance value from one inductor so I decided to tap between the points ...
117 views

### Electric grid power transformer winding: If it is milliohms, why does 9V DMM show infinite ohms?

When testing large MVA power transformers, like 66kV to 16kV, the winding resistance in DC ohms is milliohms. It takes a high current supply to do this, then the V is measured across the winding to ...
1 vote
62 views

### Winding arrangement in small toroidal mains isolation transformer

I got a 0.3A 220/220 toroidal transformer with the primary (red wires) on the outside and the secondary (black wires) on the inside. What is the reasoning behind this arrangement in this particular ...
• 817
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### Why duplex lap winding has twice as many current paths as simplex lap winding?

I found the statement of question on page 346 in the book "Electric Machinery Fundamentals, fifth edition" written by Stephen J. Chapman. When I searched for how duplex lap winding looks ...
• 175
827 views

### Grinder hums but won't run. Capacitor seems good, and so do windings

My Grandpa gave me a bench grinder recently to fix. He said he was using it a lot, grinding and grinding, then he heard a pop, and it stopped working. Now it just hums, and starting it by hand doesn't ...
• 105
1 vote
77 views

### Ferrite Choke wiring, understanding the datasheet and how it affects the signal

I've been tasked with digitising an old analogue product for my company. I'm attempting to reverse engineer the analogue circuitry with no documentation (it was designed by an outside consultancy 30 ...
• 571
886 views

### What are the properties/advantages of concentric winding?

I have seen several 4 pole induction motors that have coils wound like this: Both the main winding and the auxiliary winding have 2 pairs of these coils. This is concentric winding and I've only ...
• 623
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### Is there any way to wind this 4 pole motor to behave as 2 or 8 poles properly?

I got an induction motor in a junkyard, a WEG motor made for an Electrolux washing machine. It is a single-phase 1/2 hp 4 pole motor. It runs in 127 V and has a 40 uf capacitor feeding the auxiliary ...
• 623
79 views

### Linear variable differential transformer operation as load position feedback

I was doing some research on servo position systems and saw that Linear Variable Differential Transformers are used as feedbck systems that feeds the current load position to an error detector. So I ...
1 vote
164 views

### What is this symbol on a schematic for an old milling machine?

On the schematic below, I'm having trouble identifying what the symbol drawn on top of motors 2 and 3 means. I've never seen anything like it. They're only present on the high-power spindle and feed ...
• 1,126
289 views

### Can we use Litz multi-strand wire as Tesla coil secondary?

I am making a mini Tesla coil as a proof of concept. I was thinking, can we use multiple enameled copper wires as the secondary? (Edit: Every wire is individually enameled and the ends sanded to ...
41 views

### Need help grasping the routing of coils for stator and rotor

I can see it with just a 3 coil motor, whether it be in different configurations, but loads of different motors have some 72 or umpteen different stator slots and winding for the rotor. It was my ...
1 vote
114 views

### swapping the ground reference on a transformer's secondary winding

I'm looking to build a [simple] high voltage power supply in order to make electrets via corona discharge. I'd like to be able to fabricate both positively and negatively charged electrets using this ...
• 11
106 views

### How to find the 120 degree phase angle in a single layered lap winding of a synchronous machine?

Ok, so I have a 4 pole synchronous machine with 24 slots meaning each slot has a phase difference of 30 degree with respect to each other. 1)That means pole pitch is 180 degree for a full pitched ...
111 views

### Obtaining constant mechanical energy from a DC Machine [closed]

Out of the five types of dc machines: Separately excited shunt dc motor permanent-magnet dc motor series dc motor compounded dc motor which one will be the best for obtaining constant mechanical ...
1 vote
532 views

### Which winding is the auxillary winding in a permanent split capacitor motor?

I have an induction motor, I'm very sure its a permanent split capacitor motor. One winding is 16 ohms, the other is 4 ohms. I have seen that the higher resistance winding, the 16 ohm one, is the ...
• 105
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### A coil I built has divergent measurements respective to wire resistance and AWG size

I'm not exactly into building precision coils, but I decided to make one for a subwoofer voice coil. I used what was supposed to be AWG 28 wire, it completely fit the diameter. I wound it tightly ...
• 623
1 vote
98 views

### Shielding mains transformer to decrease interwinding capacitance

Has someone tried to shield mains transformers in order to decrease the interwinding capacitance? I have a transformer (toroid, power is about 5 VA,) and interwinding capacitance is a problem. As ...
55 views

### Is the formual for winding distribution factor and winding pitch factor for n-phase (intergal-slot winding) machine as 3-phase machine?

[] 1 In Image, alpha is the slot angle and eta'v' is harmonic-ordinal, q= solts per pole per phase [2]All book provide formula for 3-phase winding, and so far no material for n-phase winding. ...
2k views

### Center-tap transformer current calculation

I have a transformer with two secondaries, one is 24 V / 500 mA and the other is 12 V / 200 mA. I want to wire them in series to make a center-tap transformer: simulate this circuit – Schematic ...
• 2,036
163 views

### Impact of Transformer Ratio to Performance of Transformer

Based on my initial calculation, the primary inductance of my transformer will be around Lp = 351uH. This 351uH is designed with switching frequency of 55kHz for AC-DC flyback converter (DCM). By ...
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### Transformer auxiliary winding

I'm designing an AC-DC based on the UCC28780 active clamp flyback controller . I have a question about the primary auxiliary winding that is supposed to power the UCC28780 and the gate driver. My ...
• 11
116 views

### DC motor accuracy with encoder

I am building a coil winding machine and I've already set up something that works. I used two nema17 stepper motors and tb6600 stepper driver cards. The problem is that motors are seems to overheating ...
11k views

### Why don't the currents clash in a 3 phase delta connection?

Consider 3 windings, a, b and c. L1 is connected to A, L2 to B and L3 to C. The 3 windings are then connected in delta. If we could freeze frame the voltage waveform where L1 and L2 are positive ...
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### Why is there a resistor between the primary and the secondary winding?

I recently opened up a linear power supply and found out it has a resistor of 8.2M ohm between the primary winding (specifically in the neutral) and the secondary winding of the step-down transformer. ...
• 135
384 views

### Transformers: Short-circuit test

In a short-circuit test where the secondary winding is short circuited, how come the primary voltage isn't zero (in real life) when it should ideally be zero?
• 23
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