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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52 views

SiC MOSFETS power dissipation; for heat sink sizing

I want to calculate the max. power dissipated for SiC Mosfet in a 6.6KW CLLLC resonant converter with full bridges on primary and secondary sides. Let's consider the case when the input voltage is ...
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80 views

Proper usage of a center-tap transformer

I'm attempting to design a high-precision voltage source for use in an optics lab. My starting point has been the application notes provided by Analog Devices; specifically, Fig 16: The transformer ...
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39 views

How to characterize a wideband RF ferrite transformer

Transformer models incorporating intrinsic and parasitic elements are well known: The mutual and leakage inductances are calculated from measurements of the primary and secondary winding inductances ...
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157 views

Update very old, very low voltage (10V) Nutone doorbell system to new 16V chime

I have a Ring video doorbell that is connected and functioning to the old doorbell wires, which I measured at 16V. I also have a old Nutone Scoville 10 V, 5 VA transformer tucked in a very hard to ...
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1answer
107 views

Can I use this transformer for a DIY spot welder?

I have the following transformer out of a UPS: Is a good idea to use it in order to convert it as a Spot welder? I am worried about the flimsy cables on the High Voltage side.
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51 views

Creating a low power, high AC current using a current transformer?

I want to create 0-32A AC to test 1:2000 current transformers with. Create the current in a rough way, use a scope probe to measure RMS and verify calibration of current transformer circuit under test....
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98 views

How to mitigate/stop voltage spikes when turning AC transformer on and off

I wish to use a certain transformer in a project of mine but when I power the transformer on or off I see a series of large voltage spikes on the oscilloscope. The project is a DC power supply. The ...
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34 views

Weird MOT current measuerements

I have MOT transformer, which I want to use for DIY spot welder. I measured 0.85V on one turn of primary open circuit, it means cca 2.55V on three turns etc. This seems ok. What I do not however ...
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47 views

Identifying and finding a replacement audio signal transformer 50 ohm / 0.5 ohm

I am trying to identify and find a replacement for the attached transformer. The green/white leads with the red center tap have a 50 ohm resistance. The side without the center tap has a 0.5 ohm ...
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69 views

How do we check core?

I found few ferrite cores recently from my tools box they are T60006-L2063W517 -- Ferrite Toroids / Ferrite Rings Core 63x50x25 58.6uH@10kHz well my question is, how do I check they are in good ...
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60 views

Can anyone help me identify this transformer?

I'm trying to make a project using used part from a radio with my basic electronics knowledge. I want to convert this AC 9.7V to a steady DC 3V using a diode bridge so I need to know what I'm working ...
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2answers
126 views

Is there a safety issue with adding a grounded transformer to an ungrounded network?

Scenario: Installing a grounded center-tapped transformer in an ungrounded system on a ship. We have eight 11 kV to 460 V ungrounded three-phase delta-to-delta transformers feeding as many ...
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50 views

How to find a transformer for a dry cleaning machine?

My dad asked me to help him find a price estimate and figure out the ordering process for a new transformer for his dry cleaning machine. He's not that fluent in English and isn't too comfy using the ...
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24 views

Is a high open circuit voltage still beneficial when you have a high voltage/frequency pulse arc starter?

In welding, I know a high open circuit voltage is a major factor in the strength/quality of your arc when you scratch start, but how much of a factor is it when you have a pulse starting mechanism? Is ...
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32 views

I want to show that full wave rectification equation is correct by Proteus

I want to verify the full wave rectification equation using Proteus, but I get wrong voltage values. Please if any body knows how to do it, tell me.
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87 views

Is the transformer working and possible identification

Unfortunately 2 nights ago, my 120V stereo was plugged into a 220V socket directly. (I'm just about talking to the offender again). The stereo now ceases to function more or less Radio, tape player, ...
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51 views

Can I build a 3-phase transformer bank out of single transformers of different KVAs?

Can I build a 3-phase transformer bank out of single transformers of different kVAs? Can I build a 3 phase transformer bank with 2 transformers of additive polarity and 1 of substractive polarity? The ...
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1answer
31 views

Transformer Open-Circuit & Short-Circuit Tests

I need to find the losses of a transformer through simulation. I am measuring voltage, current & power. I know the method to find the losses but I am unsure if I should use the rms or peak values ...
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46 views

RF ferrite core inductor airgap magnetic field calculation

I was interested which formula I could apply to calculate the maximum field strength in an airgap located within an ferrite core, in my particular case I am looking at a "binocular" type ...
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1answer
38 views

Reading current with YDHC SCT013 split core transformer and RPi or Arduino

I've got a few split core current probes YDHC SCT013 that I used to use with an Open Energy Monitor module that has failed some time ago. Now I'm looking at building a replacement power monitor ...
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2answers
58 views

Terminal vs induced voltage for a transformer with respect to the voltage rating

Suppose we have a 2200/220 V non-ideal transformer. Based on the image below of a non-ideal transformer, would 2200V be the primary terminal voltage (V1) or the primary induced voltage (E1)? Similarly,...
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33 views

Safe Variable VAC Power Supply using Switch

I want to make a variable VAC power supply, maybe using 3-5A transformer. I provide the simple circuit diagram below. What should I add to ensure its safety? Thank you.
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1answer
69 views

Switching between ac-to-ac transformer taps in regulated linear voltage power supply

I am new to electronics and working on building regulated linear bench power supply 0v to 30v, 3A as my first project. For better performance, wanted to switch between multiple tapas of ac-to-ac ...
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69 views

Floating voltages and current path between isolated circuits

I have a bit of trouble understanding floating voltages. I thought about quite a few circuits and scenarios involving isolation transformers and floating voltages but something is still off. Here are ...
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37 views

Connect multiple bipolar PSUs to one torroidal transformer with center tapped secondary winding

I'm currently starting my ventures into building a modular synthesizer in eurorack format and am currently using a single power supply like this with a 12V AC wall wart: Source: http://...
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87 views

Can I use a laminated silicon steel transformer core as a low frequency boost converter core?

Since laminated silicon steel is used in low frequency transformers, can't I also use it as an inductor in a low frequency boost converter, at maybe 100Hz, theoretically shouldn't this work as well as ...
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44 views

AC Power Isolation

I need to supply isolated AC power to some test equipment. As far as I know, isolation transformers are used to do this. However, to supply 40 Amps from 220VAC 50Hz as isolated power, the needed ...
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60 views

Parallel Primary Coils of Two Different Transformers

Attached below please find a figure1 which is what I want to achieve (i.e. split a balanced audio line into two isolated outputs in a passive manner). The transformers that I currently have are 10 kΩ:...
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91 views

Why does LTSpice take so long to solve this circuit?

Using a technique to model transformers for a wide frequency range, I got at a circuit like this one: https://1drv.ms/u/s!AhR86nrv-ZA7ivoz9BZIoXfs4GwXIQ?e=L6mcKd LTSpice takes a long time to solve ...
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141 views

Simple RC circuit connected to Transformer

I am trying to understand about RC circuits and am having confusion understanding power out of the secondary on an ignition coil with a simple RC circuit as load. The output of the secondary coil is ...
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65 views

Balanced and unbalanced short circuit voltage of transformer

This might be trivial, but I'd like some hint on where to start. I'm calculating power flow for three-phase-four-wire distribution networks. Positive sequence and zero sequence short circuit voltages ...
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40 views

Transformer coil (reactor) inductance value in AC (El type)

I want to use one of these inductors (EI type transformer coils with air gap) in series to a speaker (woofer) to filter out high frequencies. https://www.hammfg.com/electronics/transformers/choke/195-...
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1answer
56 views

How to troubleshoot low-voltage home lighting system from 50s

My home, built in the 50s, has a Sierra low-voltage lighting system, where low-voltage 24DC switches control relays that power the normal 120AC lights. In the last week, the switches have failed ...
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37 views

Need some suggestion on 220 - 3.3 volt 500 mA power supply (Or 12 volts maximum)

I was planning to make some 220-3.3 volts,5 volts & 12 volts power supplies. I tried the configuration above in proteus (0.47uF, 275 volts RMS, Polypropylene film capacitor in series with a small ...
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41 views

Transformer with diode to provide a battery backup

I have a small solar setup running with a low capacity battery plus a 100w solar pannel and i have 3 raspberry pi's getting juice from it. The thing is that sometimes with a cloudy day i can have my ...
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72 views

Using three-phase transformer in reverse

I'm in the US and installing a 45 kVA 480 V/208 V transformer in reverse, to power an electric car charger that requires 480 V. The secondary of the transformer is in wye configuration and I will be ...
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66 views

Spark Gap Circuit Creating Unpredictable Current Spikes, What is Causing This?

I have recently been messing around with bug zapper / spark ignitor circuits as a way to learn more about high voltage electronics (This is my first foray into high voltage territory other than a few ...
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154 views

Servo motor and EMI noise on peripheral devices (microcontroller)

I have 6 servo motors (DELTA ASD-A2-0121). Peripheral devices are affected by EMI noise (When motors are in on state and have no movement). I have changed the ground system from series mode to ...
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45 views

Transformer hum coming in audio amplifier

I made an audio amplifier with a 6283 IC. When I power the amplifier with a 12V battery it works fine without any hum. When I power the amplifier amp with a 12V powered transformer, hum comes from ...
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1answer
81 views

How can I connect mains to a 230V heating band?

I am planning on using some 230V heating bands for a project of mine. I was wondering what kind of equipment I would need to connect this heating band, which has +,- pins to mains. What kind of ...
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36 views

Can I meet NEC class 2 or 3 requirements by fusing a 120v circuit at 0.5a?

I am installing a device that operates at 120 VAC, and I wish to use a class 2 wiring method. The device is rated at 0.1 A, and I want to know if I can simply fuse a 120 V circuit to meet class 2 ...
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1answer
84 views

SMPS transformer secondary voltage drift

Please see the simple SMPS buck circuit below (24V to 12V) Notice the load on the 'first' secondary coil is about 100mA (marked 'fb' This coil is used as the feedback to the MC43063 to regulate the ...
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1answer
119 views

Relationship between input power and output power of a boost converter and transformer circuit

simulate this circuit – Schematic created using CircuitLab I have a few questions regarding variable power supply units powering boost converter circuits with transformers and the relationship ...
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27 views

How much self induction would each coil of a transformer of one to one ratio be if the kVA rating for that transformer is 160?

Assuming a current load of 80 A, and a voltage load of 1600 V, the straightforward kVA rating would be 128. But adjustments are made for power factor correction and other considerations raising the ...
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33 views

Open-Delta 3-phase transformer kVA rating

I have a V-V three-phase transformer supplying a 50kVA balanced three-phase load. I know that the apparent power of a three-phase transformer \$S_{3\phi} = 3VI^*\$ and that of an open-delta system is \...
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2answers
205 views

What is the pinout of this transformer?

I have a large transformer and I just can't figure out its pinout. I simply want to make a high voltage circuit but can't find the proper coils. One side has 2 wires whose resistance is 0.8 ohms and ...
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66 views

How to calculate this capacitor value?

How to calculate this capacitor on pulse transformer primary? I've tried 470 nF but the PWM on capacitor's output lost its level, normally both PWM are 0 to 12V, but when I put this cap, the PWM on ...
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1answer
31 views

Impedance matching (RF transformer) - Impedance dependence

I'm using a TC2-1TG2 1 to 2 impedance trasnformer. I want to convert a 50 ohm load to 25 but I'm finding that the transformer only works for 50 to 100 as seen in the following simulation: Is there ...
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98 views

How can I calculate the voltage on the load with an UNUN (unbalanced-to-unbalanced) RF transformer?

I'm having hard time calculating how much RF voltage would be applied to the load in presence of an RF transformer (Unun with a specific ratio). Let me draw a simple circuit diagram. The AC power ...
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1k views

3 phase transformer efficiency calculation

This is an assignment. No matter how hard I try the answer is never what I expect. Here is the question: Three single phase transformers, each rated at 12 kVA, 120/240V, 60Hz, are connected to form a ...

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