All Questions
Tagged with protection power
43
questions
0
votes
2
answers
102
views
How does a voltage surge/spike affect the wall wart power supply's secondary side?
In the photo, you can observe an old-style adjustable wall wart AC to DC power supply, typically composed of a primary winding, secondary winding, rectifier, and capacitor. If a voltage surge or spike ...
- 299
0
votes
2
answers
99
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Not able to correlate the graph and table for the I2t rating in a fuse datasheet
In the datasheet, the I2t rating of a 5A fuse is 0.055 at 10 times In.
Using the same value to estimate the trip time for the 10 A condition, I get 0.0022 seconds. In the graph below, it comes ...
- 3,032
0
votes
0
answers
42
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What do the following parameters indicate in a resettable fuse?
I am not sure how to decipher the Pd and R1max info in the below datasheet.
Does PD indicate the tripped state power dissipation or maximum power dissipation under non-tripped operation?
If you ...
- 3,032
3
votes
2
answers
392
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What is the best way to mitigate the spark when a PCB is connected to power?
I'm designing a moderately powerful motor controller (integrated into a product). The board runs on 24V and has a 100uF electrolytic input cap, as well as 2 10uF ceramics near the switcher.
Whenever I ...
- 7,119
0
votes
1
answer
160
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Reverse current blocking for P-channel MOSFET
I'm using a P-channel MOSFET Q57 as a switch for current from VIN_ALW_GATED to +VIN_ALW when VIN_ALW_GATED > 17.259 V.
In case VIN_ALW_GATED was not connected to any reference voltage (floating), ...
- 1,067
1
vote
2
answers
259
views
Is it possible to limit circuit and protect to 5 V whilst having a 5 V USB power in? I need around 1A current
I have a USB-powered circuit and would like to limit the voltage to 5 V for overvoltage protection.
I also require around 1 A for potential current draw.
Is this possible? Most solutions I find have ...
- 25
-2
votes
1
answer
123
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difference between N and X relays?
I have seen in some SLDs for overcurrent relays there is a X unit and N unit. I understand that the N unit grounding relay is for zero sequence and the G unit is sensing the current flows through the ...
24
votes
3
answers
8k
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Scam? Does having this capacitor wired as shown provide any surge protection?
Bought this on Amazon as a dryer 240V SPD. I was trying to find out if this device is an outright scam. I found a similar post on here from several years ago but that did not answer my question. ...
- 425
-1
votes
1
answer
178
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Grounded Reference Power Supply Output Problem
I have several cabinets. Each cabinet have 24V power supply that has option to select ground reference output or floating reference output. Please look at the picture, at the bottom of power supply, ...
2
votes
1
answer
949
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Calculate zero sequence voltage and current in a HV network with one source and two feeders
My goal is to prove the direction and magnitude of Uo and Io seen by the two protection relays during a single phase to earth fault in LINE 1.
By my understanding this can be done by setting up a ...
- 23
1
vote
0
answers
5k
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UC3845 flyback add a OVP (OVC) protection
I built SMPS based on this schematic:
It's working nicely - I recalculated transformer and flyback to 24V, I used EI33 transformer with airgap (put 6 pieces of paper between halves of the core). I ...
- 626
1
vote
0
answers
92
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Will this circuit damage my Raspberry Pi GPIO?
I'm making a circuit te be able to shutdown my Raspberry Pi after the shutdown sequence is complete to avoid sd card corruption. The circuit looks like this:
A little explanation:
The battery input ...
1
vote
1
answer
4k
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Zero Sequence current Understanding
In literature zero sequence current is called DC component. If it was DC component then how a zero sequence current in neutral grounded secondary of a transformer cause current in neutral grounded ...
- 112
0
votes
1
answer
2k
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Choosing the right PTC Resettable Fuse for a protection circuit
Power shield protection circuit specs
Hello! Iv'e been creating an ESP32 power shield and started designing the protection circuit for the power supply with the following features:
Reverse polarity ...
1
vote
1
answer
344
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How to calculate the power rating of zener diode for flyback protection?
I'm trying to calculate the power rating for the zener diode I'm using on my circuit for flyback protection.
For example, if a flyback event occurs, the cathode of the zener diode is having a 30V ...
- 201