Questions tagged [fault]
161
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why there is a spike in reactive power when clearing the fault in a Fault ride through for PV plant?
I am performing the FRT for PV plant. I am not able to understand why there is a spike in reactive power when clearing the fault. In addition to this, can anyone please also guide why there is not a ...
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Laptop fan spinning clockwise and anti-clockwise - hardware or software problem? [closed]
I have a laptop fan that sometimes spins clockwise and sometimes anticlockwise. The fan is connected with 4 wires.
Support says that this may be a software problem and can be fixed with a bios update. ...
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Fault injection in Cadence Xcelium
I have a functional RTL simulation. I would like to check if bit flips at certain critical moments can cause errors in the circuit outputs. In the testbench, I can only manipulate external signals, ...
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30
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Offline open circuit detector for PM DC motor
How can I create a circuit to detect if a motor is connected or not without running the motor?
I'm designing a power wheelchair and need to implement an offline open circuit detector for a Permanent ...
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PIR sensor and its working
I have been designing a PIR sensor circuit for occupancy sensor. We have been facing problems like fault detections most of the time when we turn on air conditioning. There is also issues like the ...
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52
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How to track down <100µA earth leakage on DC rails
On our subsea robot, we have an isolated power supply (converting 3-phase AC into 320 Vdc).
For security reasons, we have a line monitor monitoring the resistance between protective earth and both 0 V ...
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DRV8262 not working with PWM signal
I designed a motor driver with the new Texas Instruments DRV8262 at its core. It will be used in robots controlled by an ESP32.
It works well when using non-PWM signals to switch the outputs in PWM ...
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59
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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 ...
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87
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What might cause this strange pattern on an LCD monitor?
Recently my laptop has been showing a strange effect on its monitor:
This is supposed to be a black screen, but the bottom fifth or so is affected by some kind of interference pattern. The pattern is ...
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Ground fault detection on an ROV
I'm helping my friend's kid with a school project where their team has to produce a small ROV. Most of their design I was able to review and help make corrections with them but I'm stumped at one ...
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LM317 does not regulate 12V to 8.2V
I am working on a project for which I needed to design a small linear regulator circuit in order to supply 8.2V for reading out sensors. I chose to use LM317, since it is quite simple to design and ...
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Why does adding this capacitor cause other segments to come on when they should not?
I have designed and built a clock, that uses a microcontroller to drive a 4x7 segment common-cathode display. Each digit is driven sequentially, with all appropriate segments of that digit driven in ...
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Ground to L1 in 3-phase have almost 0 V potential
I am in Peru and was helping check ground rod to line and neutral and see higher than one leg to ground voltage. This is at a plant with 3 phase power 220/440 volts. The local utility doesn’t provide ...
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Which faults of dual transistors on isolated dice must be considered according to IEC 60335-1?
I got the task to upgrade one of our products to comply with the requirements of IEC 60335-1, which means, that no safety function must be lost in case of a single component fault. To save space and ...
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Help IDing a high-power IC - OODOW 836 T57
I'm fault finding for a Korg M50 Synthesizer.
Symptoms: on every boot a message appears saying the device is updating the left/right control panel firmware, after which it requests a re-boot. ...
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How to calculate short circuit current contribution of a PV plant into network?
I want to calculate the short circuit current contribution of my PV plant. I have only data from the inverter manufacturer but I am not sure if I have to simply add up all the inverter's short circuit ...
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Is there any way to easily gain access to "actual ground" in an IT grounding system?
As the title asks, is that possible? By "easy access" I mean through some connection I can find inside my home, rather than burying my own grounding electrode and running wires from it to ...
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Troubleshooting a new PCB
I designed and got a PCB manufactured for the first time, and have soldered the component and powered it up. However it is not behaving as expected. I think I may learn something by everyone here for ...
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Do I need to ground the thermal pad on the MAX8808?
I have designed the MAX8808 LiPo charger IC into one of my designs. It doesn't seem to be working, in the sense that no current is flowing into the LiPo cell, despite all of the DC conditions ...
- 27.6k
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193
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Information leakage due to fault propagation in XOR gates
From the paper Fault Template Attacks on Block Ciphers Exploiting Fault Propagation, in the concept of Automatic Test Pattern Generation (ATPG), two events are required to perform in sequence: Fault ...
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What is the phase displacement of fault currents on each phase in a symmetrical fault?
In a Line-Line-Line-Ground symmetrical fault, is the fault current on each phase also displaced from each other by 120°?
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Do you think the output voltage is caused by an old capacitor?
I have a vacuum tube power supply which isn't producing the correct output voltage. I have removed the tube and all that is left is the transformer, inline 22 ohm resistor, CR201/202, R202/203 and ...
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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 ...
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143
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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 ...
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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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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 ...
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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 ...
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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 ...
- 27.6k
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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 ...
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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 ...
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366
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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 ...
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273
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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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248
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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 ...
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593
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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}{...
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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 ...
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194
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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 ...
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973
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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-...
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127
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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, ...
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246
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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?
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696
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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 ...
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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 ...
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1
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83
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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, ...
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93
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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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138
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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 ...
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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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2k
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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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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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1k
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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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165
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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 ...
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267
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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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