Questions tagged [fault]

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2 answers
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Sparking when using multimeter

I was trying to measure the voltage across two connectors that connect to a 3-pin, 13 A plug as part of troubleshooting, to verify I had circa 230 VAC present. However, when I connected my multimeter ...
0 votes
0 answers
90 views

Transformer output too high. I'm sure this should be 12V but it is outputting 25V

I have a faulty circuit board taken from a garage opening unit powered by a transformer. I have 25V from each of the transformer terminals (4 of them), 50V on the 24V relays and all terminals have ...
0 votes
0 answers
36 views

Short circuit delta

Assuming I have the following system: and a single-phase fault is on the 2.4 kV side. How do I calculate the voltage between the neutral resistor and ground? How do I calculate the zero sequence ...
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0 votes
0 answers
43 views

How is a fault location detected in a power system?

Electrical transmission lines can face various types of short-circuit faults, for example, line-to-ground, line-to-line, etc. How do power system engineers find the fault location by observing from ...
6 votes
5 answers
2k views

Is it possible to make an MCU hang by messing with its power?

We have a bunch of ARM microcontrollers on test at the moment. The test runs for 360 hours and mostly completes without a hitch, but very occasionally, one of the microcontrollers will hang. We have ...
  • 26.5k
4 votes
0 answers
119 views

Can chips be sensitive to mechanical stress after an electrical incident?

Is it possible to electrically damage a microcontroller (or any chip) in such a way that it becomes very sensitive to mechanical stress? Some background: We are developing a board with 7 identical ...
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1 vote
1 answer
34 views

Is the same overcurrent relay used for both phase-to-phase faults and 3-phase faults?

In MV grid with no distributed generators, 50-51 overcurrent relays are used to detect both phase to phase faults anf 3-phase faults. In Italy, time independent characteristics are used inside these ...
0 votes
0 answers
33 views

Fault analysis- per unit query

im trying to do fault analysis on image 1. I was little confused for the line as there wasnt a j component so unsure how to find the pu. In images 2 and 3 show a line with R+jX and the R id ...
1 vote
1 answer
88 views

CAN bus fault protection

Question: Is there a way to implement with discrete components the 70V CAN bus fault protection found in some transceivers, such as TCAN1051H-Q1 ? Background: We are using the CAN transceiver ...
0 votes
1 answer
107 views

All Mosfet terminals internally shorted in voltage controlled resistor

I was planning on making a voltage controlled resistor using a power MOSFET in order to load one 12V lead acid battery. I tried implementing the circuit below; everything was going well for a few ...
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1 vote
1 answer
59 views

Fault impedance type?

Usually fault impedances are resistive type. But is it possible to have a mix of resistive and reactive component in fault impedances? Looking at many simulation tools, they give the possibility to ...
0 votes
0 answers
17 views

model of 3 phase induction motor with asymmetric windings considering line neutral voltage

I'm doing research on modeling of inter-turn short circuit model. I looked up some papers and built the model. The current did display features of this fault, but when it comes to voltage, the issue ...
3 votes
1 answer
125 views

Actual Line-to-Line voltage from per unit value

In this question, I am able to find the per unit phase voltages using the symmetrical components. Taking the base MVA and base voltage to be the same as that of the alternator, \$ (I_a)_1 = \frac{E_a}{...
1 vote
1 answer
251 views

Insulation monitoring device for electric vehicle

Good day to all! I am planning on designing an electric vehicle architecture from scratch. My main DC bus voltage is 400 V. However, I have got different voltages in my system. I have got a 600/400 V ...
2 votes
1 answer
121 views

What can cause a surge in one 110 V line feeding a 240 V appliance, melting the connector?

One of the Hot wire (#10/3) going to my oven appear to have experienced a sudden very high in rise temperature inside the junction box, melted the connector, creating a contact with the face plate ...
0 votes
1 answer
226 views

Why is the line-neutral fault current 1.5x higher than the line-line fault current?

My commercial wiring textbook and several documents discussing fault current calculations stated "The L-N fault current is higher than the L-L fault current at the secondary terminals of a single-...
1 vote
0 answers
37 views

Get alpha-beta plot of Clarke Transform in Python

For a project I'm working on, I want to use the Clarke Transform to detect faults in a power system. To do this, I already wrote a script in Python which returns the sine wave behavior of the Alpha, ...
0 votes
1 answer
89 views

Difference between a relay and a fault passage indicator (FPI)?

What is the difference between a fault passage indicator (FPI) and a relay (for example relay 50, 51, 67N) ? Are they the same thing?
0 votes
1 answer
160 views

My light-dependent resistor gives a fluctuating serial output

I'm a high school student trying to make a light tracking single axis solar panel. I am using an Arduino Uno rev3 board. When I first finished building it, the system failed to operate. I spent a few ...
1 vote
0 answers
62 views

How to test if a domestic 3 phase power company meter is reading wrong?

BACKGROUND: Domestic 3 phase 220VAC supply in Thailand. Power company meter is 4 wire GE 3 phase 15A/45A. Massive power bills when mains breakers were turned off (back in home country for 9 months ...
0 votes
1 answer
81 views

How did they arrive at an expression for resistance given the power of the load?

In Anderson's 1995 Analysis of Faulted Power Systems, there is the below example I am required to calculate the sequence network for the fault occurring at C. To calculate the resistance of the load, ...
0 votes
1 answer
88 views

How to reproduce these audible clicking or popping sounds? [closed]

My fluorescent lamps (and other devices) are making clicking sounds. I want to reproduce these clicking or popping sounds or get an idea of how one might produce such sounds in electrical devices or ...
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0 votes
0 answers
75 views

Bench PSU leaking voltage to case and not working properly

Tl;dr at bottom Recently I found old bench power supply in my closet and tried to test it but display kept on displaying 0.00v and 0.00a - the power supply is voltage and current regulated and has two ...
0 votes
1 answer
31 views

Is the impedance bus matrix method the same as the Ohmic method in power system fault analysis?

There are a few methods to do power system fault analysis, like the per-unit method, MVA method, and impedance method (Ohmic method.) I am doing fault analysis using per unit symmetrical component ...
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1 vote
3 answers
666 views

Would ground fault cause breaker to trip if neutral not bonded to ground in main panel?

Suppose normal residential main breaker panel (not subpanel) is wired correctly except the neutral bar is not bonded to ground. Assume a 15A breaker in the panel powers an exterior light with a metal ...
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3 votes
1 answer
87 views

Fault Ride Through requirements for wind turbines

First a short introduction: (the question is below the first image). The capability of fault ride-through of wind turbines is the most important requirement related to national grid codes. Based on ...
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0 votes
1 answer
300 views

What is the fault level of paralleled transformers? [closed]

When paralleling transformers the fault level at the bus is it the sum of the individual transformer fault level?
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0 votes
0 answers
75 views

Reason behind coil melting

Today I managed to melt the ignition coil of my RC engine. First let me describe my circuit, I have also created a diagram, however I could not find all the parts in the designer so I think some ...
-1 votes
1 answer
98 views

Can a solid state relay be energized from the same 120V AC source that it switches?

Can a 120V AC input / AC output solid state relay be energized with the same 120V source connected to its contacts? This can't be done with an electromechanical relay because it generates feedback and ...
1 vote
2 answers
46 views

Opamp input fault current limit vs fault duration

A usual datasheet rating for maximum allowed input current into opamps is 10 mA. Initially I thought that this is some kind of DC limit of what the clamping diodes could handle before thermal ...
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0 votes
2 answers
643 views

Very hot live pin on kettle plug

I moved my kettle just after boiling it yesterday and noticed the live pin was very hot. None of the other pins are hot. It's a bs 1363 type plug and socket. And a <2 year old kettle. After a full ...
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0 votes
0 answers
42 views

Fault recovery of a UAV using MATLAB

I'm currently investigating fault recovery in a UAV using MATLAB. I've been given several variables: phi = the roll angle psi = the yaw/heading angle beta = the side slip p = roll rate r = yaw/...
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2 votes
1 answer
148 views

Symmetrical Components - Three-phase D-Y transformer with unbalanced voltage and loads

I have a Delta-Wye transformer, N1/N2 = 4, and am trying to solve the circuit below, with 120VAC applied to terminals VAB only. On the secondary I have 1 ohms connected between a-n and 5 ohms between ...
1 vote
1 answer
67 views

7408 quad-AND with diode latching: sporadic (and undesired) self-latching at power up

As an introduction to electronics, I am still working my way through Charles Platt's Make: Electronics (2nd edition). This issue is about Experiment 21: A Powerful Combination In circuit on ...
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-3 votes
2 answers
348 views

Falstad - a bug with mosfets?

I have a schematic in Falstad. It is almost symmetrical (the mosfets are connected by drains and "SWAP D/S" is enable in the second mosfet to be able to connect both). And this symmetrical ...
0 votes
0 answers
54 views

Detecting a high-resistance fault location (like corrosion)

I recently encountered a problem where i had a 2 wire cable, one wire with corrosion somewhere and the other wire is perfectly fine. I didn't have a replacement so I wanted to try and find out where ...
0 votes
0 answers
444 views

Open circuit fault detection using an Arduino

I was able to implement short circuit fault detection of under ground cables and I was also able to add a GSM module(SIM900D) with it. I'm trying to further enhance my project by detecting open ...
1 vote
2 answers
418 views

12VDC Fan rated at 0.08A only drawing 0.04A, can I increase current draw in order to bring the rpm up?

I've built a small desktop fume extractor for soldering. It uses a 120mm 1000RPM, 12V, 0.08A case fan. Not huge, but it does the job. The fan is only drawing roughly 0.04A and I have been fault ...
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3 votes
2 answers
177 views

Fault current indicator - what should I do?

Part of the power plugs in my flat stopped working this morning. I checked the breakers box and one of the breakers was in OFF position, with a yellow indicator. After checking the producer's website, ...
1 vote
3 answers
249 views

Samd51 Handler HardFault

I am trying to upload a simple program that does nothing to my samd51. Here is the code: void main(){} I have compiled it to the exact samd51 model I have using ...
0 votes
1 answer
80 views

How to diagnose thermistor problem

I have a thermistor which I believe is a NTC 3950, and which I suspect does not work properly. It is from a 3D printer extruder/hot end. The displayed temperatures and the ones I measure using a meat ...
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2 votes
3 answers
74 views

Best way to implement a global FAULT input

I've got several microcontrollers multiple feet away from each other in a network that must be able to be put into a shutdown state all at once, ideally before power loss. I want to trigger a shutdown ...
0 votes
0 answers
204 views

How to tell if 74HC595 is dead

I just bought a few SN74HC595N and they are doing some weird stuff. I was testing them and output just does not come out. I know it's not a problem with my circuit, since I had a couple laying around ...
1 vote
2 answers
182 views

Ground Earth Resistance explained in electrical system

I have several questions about the electrical systems used in the field and the grounding mechanisms. So, as far as I understand there are multiple systems that can be used to distribute electrical ...
0 votes
0 answers
163 views

Why doesn't this Elektor ramp circuit work?

I built the following circuit on my breadboard, it is from an old Elektor article: It is a ramp generator that repeatedly charges C3 through the dual-PNP current mirror to build a ramp, and briefly ...
1 vote
0 answers
87 views

TN-S system neutral point earth resistance

According to many sources on the internet, a secondary neutral earth resistor is added at the distribution stations (transformers) to reduce the earth fault current. My question is when using a TN-S ...
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3 votes
1 answer
689 views

How can there be a zero sequence current in a single line to ground fault with an ungrounded neutral

The circuit that describes a single line to ground fault in a system with an ungrounded neutral is: I neglect capacitance between phases and only look at capacitance to ground. The definition of zero ...
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1 vote
2 answers
854 views

LTC3780 DC-DC 5-32V converter: sudden fault and overheating

I have planned to build a variable voltage DC power supply based on the LTC3780 DC-DC 5-32V converter. I guess you are familiar with the converter, but I am attaching and image for illustration: I ...
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2 votes
3 answers
2k views

Why does AC input have a parallel resistor and capacitor?

Well, I am trying figure out a situation with images and a circuit diagram. I am checking all part looks normal, but if I insert this board on a machine the resistor is exploding and one leg of ...
  • 975
0 votes
1 answer
429 views

Why does the value increase constantly and slowly in diode mode?

I am using Fluke multimeter and trying fix electronic circuit. In diode mode fluke docs, telling briefly explained how to test the durability and accuracy of diodes. The test usually runs when I touch ...
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