Questions tagged [fault]

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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 ...
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2answers
42 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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2answers
60 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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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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1answer
47 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 ...
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1answer
47 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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2answers
100 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 ...
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0answers
43 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 ...
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127 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 ...
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2answers
87 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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2answers
131 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, ...
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3answers
118 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 ...
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1answer
46 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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3answers
71 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 ...
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0answers
85 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 ...
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2answers
116 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 ...
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140 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 ...
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27 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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1answer
301 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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2answers
424 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
992 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
160 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
267 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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0answers
41 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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2answers
222 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
247 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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0answers
59 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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68 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
60 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
67 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
3k 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
771 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
4k 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
245 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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107 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
103 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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0answers
100 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
76 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
509 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 ...
1
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1answer
75 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
611 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
236 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
315 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
69 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
256 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
246 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
58 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
57 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
124 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 ...