Questions tagged [fault]

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Modelling internal fault in a transformer

I am doing an analysis of faults in transformers and i need to model internal faults in a transformer. Please do advise on how to model internal fault in Simulink. Thanks in advance
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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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1answer
65 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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1answer
65 views

LTC3780 DC-DC 5-32V converter: suddenly fault and hot

I have planed to build a variable voltage DC power supply based on LTC3780 DC-DC 5-32V converter. I guess you are familiar with the converter, but I am attaching and image for illustration. I used ...
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3answers
363 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 ...
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1answer
69 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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1answer
78 views

WAVGAT Pro Mini, no serial output

I ordered some Pro Minis however get some WAVGAT clone thingies. The first problem was it is running too slow (4x slower) when compiling with default "Pro or Pro Mini" board profile. Serial however ...
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37 views

Ground Fault Protection In Consumer Electronics

Medical devices have to meet ground fault/isolation requirements such as 60601-1 (link). Particularly galvanic isolation is required on power and data lines to avoid a fault conditions that could ...
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0answers
32 views

Do 24-volt DC arc fault breakers exist?

I've seen arc fault breakers for 80-volt DC systems, which I understand to be a requirement for photovoltaic installations. I'm interested in whether such devices exist for 24-volt DC systems. Does ...
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24 views

Finding E for generator given active power and power factor in three phase system (fault analysis)

Question:The generator is delivering 0.5pu active power to infinite bus 3 at power factor 1.0. The system experiences three phase fault on one transmission line very close to bus 2 which is cleared by ...
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2answers
50 views

Motors in symmetrical fault analysis

In three phase symmetrical fault motors(Induction and Synchronous) become generators(I guess because of the inertia). When do I take in consideration of the motors? Do I even need take them in ...
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2answers
179 views

Can an electronic system be built with absolutely no single point of failure?

Is it possible to make an electronic system, where every sub-system is duplicated and absolutely nothing is a single point of failure and if a failure (or multiple failures) occurs the system itself ...
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25 views

Does zero sequence current flow in line to line faults?

Assuming that there is a prefault load on a line,does zero sequence current flow during phase to phase faults ?
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55 views

Does this (seemingly) corrosion create problems for the operating of the chip?

We have a PCB of a VME machine of ours and it has some kind of white corrosion on it. Does this impact the functionality of the machine and what could it exactly be?
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66 views

What is the impact of Earth's magnetic field polarity on consumer electronics?

Earth's magnetic poles are known to have inverted in the past. How are commonly used circuits or component of consumer electronics (from energy production/transportation to TVs, mobile phones and PCs) ...
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1answer
58 views

fault current through a person

Say a person touches the live wire as shown in the first attachment, the current will flow through him and dissipates into the ground as shown in the second attachment right? the fault current through ...
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1answer
55 views

Power system fault analysis

I have been stuck in this problem for identify the fault location. Can anyone show me where to start on this? I'm not familiar with reading the curves so please just give me any hint. Thank you
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1answer
1k views

Difference in current transformers conection for ground fault detection

I have seen that for detecting ground faults on a 3-phase system powered by a secondary wye connected transformer, current transformers (CTs) can be connected in several ways: On the ground ...
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3answers
558 views

Line to ground faults

I am having a trouble understanding the concept of line to ground faults,and ground in general. In this simple single phase circuit, does current reach the load and the circuit operates normally? ...
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3answers
2k views

STM32F4 HardFault_Handler

I've been trying to program an STM32F412RG but my program is stucked at HardFault_Handler once debug starts. My board is an Wio LTE EU Version and I'm trying to ...
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1answer
131 views

Searching for 'ground fault' on DC power supply, 0VDC to ground

We have 3 chargers for DC power supplies (125VDC battery banks) at our facility and had a contractor come in and test them. They said there is a 'ground fault' on 2 of them in their report. The only ...
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81 views

Faults in a RLC circuit

Suppose we have a classic RLC circuit, in series and with constant voltage. Let's suppose that the resistance, the inductance and the capacitance can be affected by a fault. For which components can ...
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1answer
46 views

Power strips show fault in some outlets but not others

I'm not sure if this is on topic or not, but I thought I would ask. I have a few power strips (surge protectors) in my house that I use for computers, TV, etc. Some of these have a "fault" or "surge"...
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92 views

Calculate ground fault current leak on human contact

I am sure this is very very simple and probably realy dumb but I've been banging my head for hours and can't figure this out. Or find an answer on google/books for that matter. Even with the diagram ...
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1answer
65 views

Can a ground fault be caused by something outside the home?

Yesterday afternoon, I had a GFCI switch trip. It would not reset. I figured I had a ground fault. I left the home for a few hours and after I returned I was able to successfully reset the GFCI. The ...
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3answers
221 views

If neutral line touches the live wire, how to protect the devices connected due to neutral fault?

If the neutral line accidental touched the live wire, then due to momentary surge the home appliances connected gets damaged, what are the ways to protect the devices. Would RCCB be helpful to protect ...
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1answer
71 views

Substation grounding

I am trying to understand a grounding system for substations, fault current is something I am not getting. For example, for a small substation with some transformers, if there is a fault in the system ...
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2answers
403 views

X2 capacitor. Test if failed open

I am looking at a small board in a paper shredder (it does not work). If I apply AC power and measure AC voltage across the X2 capacitor (I think it acts as a voltage dropper for the low voltage ...
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1answer
129 views

How to build (from scratch) a GFCI Circuit? [closed]

I am looking to understand what is the circuit inside a Ground Fault Current Indicator (GFCi). What does the circuit look like? Simple google search is not yielding good results about the guts of it.
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1answer
84 views

Best way to locate a 4k stray resistance between 2 bus lines in a PCB?

I have a faulty PCB which is showing an unexpectedly low resistance between certain pairs of bus address lines. I'm measuring a little over 4k ohms between these bus lines, but according to the ...
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1answer
286 views

Linear voltage regulator failure?

I've been building USB powered audio DAC circuit which is using multiple LDO voltage regulators. I discovered one of the regulators, namely TPS79333, which is responsible for supplying 3.3V to ...
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1answer
45 views

Purpose of using per unit when calculating faults?

I read a book about power system faults - they all use per unit. They show examples of generators supplying motors through a transmission lines. They convert real voltages, powers and resistances into ...
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2answers
188 views

RS485 Multidrop Issues

I have an application where we use RS485 to communicate messages to a series of LED Displays on the bus. Our first version of the board seemed to work fine with no problems, however we have made a new ...
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3answers
224 views

Not understanding why in overcurrent protection only a certain section will isolate (why not the whole system)

I'm having an issue understanding a simple concept for faults. I understand the principles of how the relays cause the circuit breaker to open etc when a larger current goes through them to provide ...
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1answer
45 views

Voltage fault injection possible on switch output?

I am required to check that the software in a system correctly handles a fault condition from a high side power switch. The switch has a current sense pin which sends a voltage back to a ...
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1answer
43 views

Fault modelling stuck at fault for combinational circuit

A circuit has n inputs and n outputs. It is implemented only using AND, OR and NOT gates. Further, there are no fan-out branches. What is the number of s-a faults that remain after fault collapsing? ...
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1answer
99 views

Why does one of my HiFi speakers only start working after several minutes? [closed]

not sure if this is an EE question, it's the closest SE site I could see? I have a Sony separates mini-system (HCD-SD1) I was given; it's quite old now but good. Except that for a while now, when I ...
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1answer
638 views

HDMI triggering the Ground Fault Circuit Interrupters via Projector

Overview: A colleague of mine took her HP laptop from Canada (19.5 V, 1.4 A DC rated) to work in Brazil and experienced ground fault trips on the outlets when she connected an HDMI to a projector ...
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2answers
983 views

Single-Phase-to-Ground Fault doubts

I'm studying Fault Analysis Using Symmetrical Components and I have doubt over the single Phase to Ground Fault. On the book is written that generally Is and It are equal to 0 during a single-phase ...
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2answers
459 views

Ordinary Differential Relay Problem

The answer given in my workbook to the above problem is A. The things I was able to point out secondary c-phase current = 300A and other secondary phase currents = 0A since the entire current ...
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3answers
3k views

What causes a faulty Linear Voltage regulator to output wrong voltage [closed]

I made a circuit where I needed DC 8v supply. I was using a KA7808 to regulate the voltage. While testing the voltage regulator unit, I identified that the Regulator IC might be faulty because I was ...
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1answer
159 views

Why symmetrical component analysis is necessary for fault calculation?

If a 3 phase fault occurs the direct axis sub-transient reactance is sufficient to calculate the fault current. But in case of an unbalanced fault it is not. Taking the example of Line to Ground ...
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0answers
58 views

Unbalanced Fault Problem

I have attached the image of a theoretical question with its explanation given in my book. can anyone please explain this ? I am not able to start from anywhere so I can't show my work. I am posting ...
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2answers
1k views

How do solar panels affect the short circuit fault currents of a network? [closed]

As title suggests, I'm trying to find out how adding PV, both residential and solar farms, have an effect on the short circuit fault current of a network. I wasn't given much info to go off, so I am ...
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5answers
334 views

How can I protect a 12VDC power source from high-resistance shorts? [closed]

I have a pickup truck with a 3kw AIMS inverter-charger. It is wired with 4/0 welding cable (for both positive and dedicated neutral back to the alternator), and I installed a block with a 300A fuse in ...
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1answer
61 views

Historical Addressing Modes/Conditions that Complicate Page Fault Handling

I was reading this linked question and the following paragraphs stood out to me: For example x86 and 68000 had instructions which access memory two or more times. Each memory access could cause a ...
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0answers
135 views

Why won't LED light? [closed]

So I'm attempting to diagnose what's wrong with my daughters light up fidget spinner after she dropped it on the floor (and if possible fix). But I seem to be having a failing at electronics 101 and ...
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1answer
86 views

how decreasing ground fault resistance decrease the touched voltage?

Fault current = supply voltage / fault path R. Assume live conductor of 230v touches the equipment metal frame. 1) assume R path through grounding electrode 25 ohm I= 230/25=9.2A 2) R=3 ohm I=76....
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1answer
1k views

Ground fault protection for fault on delta side of a wye-delta step down.

I have a distribution circuit with a primary 4-wire 21 kV and secondary 3-wire 12 kV circuit. The two winding transformer is a (grounded) Wye-(closed) Delta transformer. I know that if I have a ground ...
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1answer
135 views

Repairing Television in Protect-Mode [closed]

My 5-year-old television (Philips 32pfl5405h/12) stopped working two weeks ago. It seems to be in protect mode as its standby LED keeps blinking three times. I pulled the plug and left it for a week -...