Questions tagged [current-transformer]
The current-transformer tag has no usage guidance.
172
questions
-1
votes
2
answers
49
views
Monitoring sub panel energy use with CTs [closed]
I am trying to monitor the energy use in a shack with a sub panel that is rented behind our house. The cheapest and easiest way seems to be an AC 100 A digital meter with split core CT. My question ...
0
votes
3
answers
154
views
What formulas and calculations are needed to ensure a 500/5A current transformer does not saturate?
I'm working with a 500/5A current transformer (CT) and need to make sure it doesn't go into saturation during operation. The core of the CT is made of mu-metal with the following specifications:
...
1
vote
1
answer
79
views
Modelling power transfer under saturation for 1:N current transformer in LTspice
A toroidal current transformer consisting of two half-toroids with air gaps, is clamped around an overhead 50 Hz AC power line carrying 50-300 A (i.e. a 1:N CT). It is used for energy harvesting.
Is ...
0
votes
2
answers
119
views
Maximizing power transfer from 50Hz AC line via toroidal current transformer
This paper looked at ways of achieving high power-to-weight ratio for harvesting power from a 50Hz overhead line.
https://findresearcher.sdu.dk/ws/portalfiles/portal/250674676/...
1
vote
2
answers
87
views
How to sample current in high-kHz to low-MHz [closed]
I am working on a project that, at its simplest, is a switching circuit (either a half-bridge or single switch) connected to a resonant filter. I need a way to measure/sample the current going from ...
- 31
3
votes
0
answers
74
views
Current Transformer: Bifilar Fractional Turn fixed compensation explained
I'm a new design engineer at a company that manufactures current transformers. When we get requests for very high accuracy, high burden CTs with a lower turns ratio (usually 600:5 or less) we're ...
- 51
2
votes
0
answers
40
views
Connecting an energy meter with 6 CTs? [closed]
I want to install an energy meter to monitor the energy consumption of a transformer. The secondary side of this transformer is a parallel circuit, making it impossible to connect three current ...
- 21
0
votes
3
answers
65
views
current transducer Burden Resistor configurations
How will the current flow? Will it go from x1 to gnd and x2 to gnd---(Rb=30ohms)
or
x1 to x2 and x2 to x1 (Rb=60ohms) and when no current is flowing r1 and r2 will act as an pull-down resistor so ...
0
votes
0
answers
18
views
Power indicator circuit with overcurrent signaling
I'm seeking advice on a circuit I've developed through experimentation, patience, and determination.
While I have a technical education in electronics and electric systems from middle school, I'm not ...
0
votes
1
answer
59
views
Ground Fault Interrupter
I was trying to simulate a circuit where it can detect grounded neutral conditions in the household. I need to have a current transformer which can detect the current differential ans sends a signal ...
- 1
2
votes
2
answers
735
views
Measure very small current with Arduino? [closed]
I have to make a circuit/device in which i have to measure very small current in a wire carrying ac current.
In a given scenario, there will be a live wire carrying as low as 0.2A and as high as 100A. ...
- 222
0
votes
0
answers
52
views
Connecting +/-4V signal to ADC in microcontroller
I want to connect current transformer do the ADC input in microcontroller. The device have analog signal output (-4 to +4V) and ADC range is 0 to 3.3V
I have PCB according to the below scheme. Is the ...
- 41
0
votes
1
answer
172
views
Explanation of the circuit diagram of a PIR sensor activated light
Can someone please explain the operation of this circuit diagram of a PIR sensor led light.
The high voltage "ground" connections in the original diagram have been replaced with connections ...
0
votes
2
answers
89
views
163 A - 400 Hz CT Testing For Aviation Generator Application
What power supply equipment could I use to provide a 400 Hz, 163 A rms supply to support the testing of a wound Current Transformer installed to an aircraft power generator?
The test requirements are ...
- 1
0
votes
1
answer
53
views
How do I model domestic power demand and identify consumers by their resistive and reactive draw?
I put a commercially available 80 A current transformer on the live tail to my domestic fuse box. I obtain readings of current draw, supply voltage and power draw.
When an appliance is turned on I am ...
- 13
2
votes
1
answer
219
views
Components Used in an Opamp Circuit Measuring AC Voltage
Why do we use this capacitor in the opamp and why do we superimpose it on the DC voltage and then destroy it again with the capacitor?
I got some answers here, but as @SamGibson pointed out, I opened ...
- 69
1
vote
4
answers
464
views
Why do we use this capacitor in the opamp and why do we superimpose it on the DC voltage and then destroy it again with the capacitor?
I am interested in the ZMPT101B circuit and there are a few things I cannot understand.
This circuit is designed to measure AC Main voltages between 50Hz and 80-250V and to be read from an MCU like ...
- 69
0
votes
1
answer
131
views
Self-powered measurement unit for current transformer
A few days ago my friend told me his end-year project about a current transformer that capable of measure current with its own instrumentation. And some concept that we discussed confused me. Let's ...
- 73
2
votes
2
answers
61
views
Designing a self-power current range detector
I need to design a current range detector i.e. a module with an AC current as input and a digital output. When the current is within range (i.e. between 0.1A AC to 2.5A AC), the output should be a ...
- 241
1
vote
1
answer
119
views
Is this a viable amplifier circuit?
I am looking to measure my mains voltage input for a power monitoring circuit. This is the first time I have messed with an opamp to read out a transformer, as well as my first time simulating in ...
- 201
0
votes
0
answers
290
views
Can a single CT Clamp go to 2 energy meters?
I have a Split Core CT CTSA016 - 100A/50mA Yuanxing CT Clamp (Datasheet) around my mains - and it is feeding into my Solar Inverter.
I have just purchased a Shelly EM 2 Channel WiFi energy meter to be ...
- 454
0
votes
1
answer
384
views
Current transformer using LTspice
I am trying to simulate the secondary current of a current transformer with the following parameters:
CT ratio 1:200
primary current 15A
Lprimary 2.225nH
Lsec 89mH
With the proportionality of ...
- 3
2
votes
1
answer
426
views
Current Transformer Current Sensing via operational-amplifier
This is a current sensing circuit, L1(CT2320) is a current transformer, U1 is generated by IGBT inverter ，U is one of a three phase of the motor driver voltage. I have several questions about this ...
- 21
0
votes
1
answer
102
views
Current transformer to DAQ
I'm using a MCC 128 HAT DAQ on top of a Raspberry Pi. I'm reading the output from an AT-50-B10 current transformer that's around the mains cable (UK) that's powering the Pi & monitor.
I'm ...
- 135
1
vote
1
answer
73
views
Inaccurate voltage reading from MCP6234 op-amp buffer circuit with Seeed XIAO nRF52840
I'm facing an issue when trying to read the voltage output from an analog sensor (current transformer) that has a DC voltage output of 0-5 V, using a Seeed XIAO nRF52840 to read the output using its ...
- 195
4
votes
2
answers
1k
views
Help understanding difference between current and voltage transformers
I did see a previous question on this but I’m still a bit lost.
Here is my simple summary: A CT and VT are the exact same thing. However in the case of a CT you design your number of turns to target ...
- 63
3
votes
1
answer
192
views
Current detector transformer on optocoupler
I need a current detector that outputs a logic signal (1 or 0). I DON'T need to measure current.
Detected current: AC.
Voltage: 220V.
Load power: ~1kW.
FOR EXAMPLE: I need a current detector that ...
- 33
3
votes
1
answer
173
views
Questions about current transformer
I am currently trying to understand the influence of the number of windings and load resistor on the current output of a current transformer (CT). My schematic consists of a CT, a load, a divider ...
0
votes
0
answers
225
views
Current Transformer HWCT004 and ESP32
I am trying to measure the AC current up to 20A flowing through a current transformer using ESP32 Development board. I have a bunch of these cheap current transformers from Aliexpress. But I am ...
0
votes
1
answer
493
views
Does this split-core clamp current transformer have a built in burden resistor?
I purchased a split core current transformer (SCT013 30A / 1V) and I want to make sure I don't need to install a burden resistor. The attached picture shows the guts of the transformer. Isn't the ...
0
votes
1
answer
296
views
How do I calculate a CT output curve when measuring through an op amp and diode?
I am designing a circuit that uses a CT sensor to measure the current in a 240 VAC line.
simulate this circuit – Schematic created using CircuitLab
I have observed the following relationship ...
- 2,123
1
vote
1
answer
158
views
How to properly measure a 200 A/5 A CT using an Arduino?
I've seen multiple projects for energy monitoring explaining how to calculate values using a Current Transformer (CT), however, all the CTs that were mentioned have high turn ratios.
The CT available ...
Kristofer
3
votes
1
answer
744
views
Proper burden resistor CT clamp
I'm trying to figure out what the proper burden resistor I should use, but the information I'm reading from OpenEnergyMonitor answer for the proper resistor values doesn't match what I was expecting.
...
- 31
0
votes
0
answers
93
views
Why does the ALF in a current transformer increase with less load on the secondary side?
I am studying measuring transformers and I recently came across an expression that implies that the accuracy limit factor (ALF) of a protection class TI increases when the secondary load decreases (...
- 81
3
votes
1
answer
742
views
Why are smaller ratio current transformers physically larger than bigger ratio current transformers?
During a presentation on current transformers yesterday, something came up that I really didn't start considering until today. The presenter said one of the biggest issues with using smaller ratio ...
- 335
0
votes
3
answers
198
views
Supplying and measuring from current transformer
I need to provide supply voltage to take measurements and also get measured signal from same current transformer, which will be placed on AC line. Current transformer parameters, such as internal ...
1
vote
0
answers
125
views
Current transformer variable burden resistor for wider current range
I want to use a current transformer to measure a 100A AC supply (240V domestic incoming supply) with a minimum current of 1mA, with essentially an Arduino. That seems quite a tricky brief so my ...
- 123
5
votes
1
answer
55
views
How can power factor be reliably estimated given the phase error in current sense transformers?
The majority of mains power sensing devices I've seen (both commercial products and ICs) utilise a current sensing transformer. Many of them also calculate or estimate power factor. However, the phase ...
- 10.9k
0
votes
2
answers
5k
views
How does a current transformer system know the direction of the power?
I know that it is important to connect a current transformer the correct way so it does not appear that the power goes from source to load.
But how does this work exactly? Since it is AC system it ...
- 131
2
votes
0
answers
67
views
Replicating the current output of a split-core current clamp
I have 6 inverters that read non-invasive AC current clamp sensors.
Each inverter reads a different current clamp, all clamped around the same 230 V wire. While this works, it is quite messy.
It was ...
- 339
0
votes
1
answer
3k
views
Simulating a current transformer in LTspice
I am trying to simulate a circuit which I purchased. It is a 5 A/5 mA CT conditioning circuit which I have attached.
I am unable to simulate the circuit, because the CT is not ground-referenced. If ...
- 83
4
votes
1
answer
190
views
Using a current transformer
I have to measure a current of 500 A (50 Hz) using a 500 A/5 A CT with a uC. In my circuit, I have a 2.5 V reference/offset and the voltage will be measured about this offset value. There are low cost ...
- 83
0
votes
0
answers
171
views
Can I use a shielded multiple conductor cable to carry current (0-100mA) from multiple current transformer clamps (CT) that sense AC current?
I need to run cables for 12 CTs (Split Core Current Transformers) that will be sensing current on multiple branches inside my outdoor electrical panel. In case it matters, it is a 240V split-phase ...
2
votes
3
answers
5k
views
What will happen if we short the secondary side of a transformer (whether step up or step down?) Why is the secondary side of a CT shorted?
I can't understand why it is dangerous to leave the secondary side of a current transformer open.
-1
votes
2
answers
226
views
What should be the core size, SWG #, # of turns for 100VA isolation transformer to run 100 watts bulb at .5 amps & 230 volts?
I am a certified computer programmer, but not an electrician. After researching on google, youtube, reading few books and referring to some local technicians, I made a transformer on a toroidal core ...
- 129
2
votes
1
answer
188
views
Wemos D1 dies in current sensing project
I'm really hoping someone can help me with this project. I've been trying everything I can to get this to work.
I have a project that senses current flowing via a current transformer (2000:1 20A max) ...
- 23
0
votes
0
answers
97
views
Type of transformer needed to measure 4-20mA process current?
I occasionally work with 4-20mA process signals and need to read the current value flowing through the wire. I now use a standard Fluke 17B+ and must disconnect the loop and add the meter in series ...
- 2,716
0
votes
1
answer
190
views
Transformer copper loss
In this Example the efficiency for a full-load transformer was asked to solve. The book calculated the copper losses after referral to the secondary side as the following : Pcu = (Is)^2Req = (65.2 A)^...
- 51
0
votes
1
answer
757
views
Current transformer with no load?
The apartment complex I’m in is only a year old, so we’re still in the Defect period with the builders. I’m on the Committee of the Owners Corporation, so I get to see the utility areas. The builders ...
- 1,493
0
votes
1
answer
247
views
How to get current value from a current transformer voltage reading value
Given the simplified current transformer setup and a transformer with 100 A : 50 mA ratio, how would I calculate back the actual current given a voltage reading on the ADC?
simulate this circuit &...
- 929