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Questions tagged [surge-protection]

Questions about protecting electrical devices from voltage spikes.

2
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1answer
32 views

Circuit protection component arrangement

I was reading this thread and decided that in general it's better to place the reverse polarity protection diode D2 after the TVS rather than before it, and to instead use a bidirectional TVS for D1 (...
0
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2answers
36 views

i dont want to change voltage but only regulate input voltage

It is my first power supply project. I will supply 300 watt vehicle audio amplifier with this supply. I will use nominal 24V and 14A at my system Vehicle input 24V and my amlifier 12V-30V but when i ...
0
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1answer
27 views

TVS diodes for Ethernet/PoE?

I am getting confused in selecting TVS diode for Ethernet Interface. Should I connect one bidirectional TVS diode across a ...
0
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1answer
29 views

Separate ground for gate opener control box?

Is it worth electrically isolating the control box of a gate opener from a well grounded steel fence? Or does the grounding of the fence have the same effect? My house is in a very lightning prone ...
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0answers
17 views

Lower VPR in SPD (Surge Protection Device) is more protective?

If you have a universal power supply that can accept 88v to 264v connected to expensive security system. Isn't it if you use a 120v SPD (Surge Protection Device) with VPR (Voltage Protection Rating) ...
2
votes
1answer
57 views

Interpretation of EN 61000-4-5 Surge requirement on a DC Power Port

I am trying to understand how to treat the DC power port on my industrial device (read: will be used in CNC machine shops and industrial processing plants and the like) should be tested according to ...
0
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2answers
28 views

Using Belkin 6-Outlet Surge Protector in Morocco without a Converter [closed]

Morocco uses the 220V/50Hz standard, and I was trying to use the following power strip I bought in the US with only a adapter (no converter): https://www.belkin.com/us/p/P-BE106000-06/ When I ...
0
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1answer
64 views

Can car alternator back-emf damage electronics?

I know on startup a motor or generator produces back-emf and current ( correct me if I'm wrong, been a while since I've worked with electric machinery ). Thus, it'd be reasonable to expect that when ...
0
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1answer
82 views

LTC4366 killing MOSFETs

I designed a circuit around LTC4366 as per the picture below. However numerous MOSFETs have been damaged and become useless. Mosfets used : STH12N120K5-2; IXFT50N85XVH; STW13NK100Z - All are rated to ...
1
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0answers
96 views

MOVs, thermal fuse and thermal runaway behavior

Above picture is that of a Belden surge protector with some kind of cloth covered over the MOV and thermal fuse for isolation to promote more conduction. I don't want to cover the whole thing with ...
0
votes
1answer
45 views

What could be the function of three components of this surge protector?

An SPD module has the following circuit diagram: I'm trying to understand how it functions. I only know the varistor symbol on the left corner I guess it is a MOV and suppresses transient voltages. ...
0
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3answers
63 views

Surge or other suppressor I can use, to prevent tool blowing fuse if blade sticks [closed]

I want to say up front, that this question involves minor modification (transient surge/current suppression) to the power supply side of a power tool. Usually I'd be the last to do anything like this (...
1
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2answers
53 views

ESD diode selection based on VCC of the IC

I have a question about TVS diode selection. This kind of question is already discussed in previous questions. ESD Diode - GPIO Microcontroller Selecting a TVS for ESD protection For protecting vcc ...
-2
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1answer
59 views

Is this a Disconnector beside MOVs?

This is inside a power strip surge protector. What is that tubelike thing between the MOVs? Is it the disconnector (written "22IR UMI, 4A, 102 Celcius, 250V")? Can anyone show me images of a ...
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0answers
40 views

LTC4366-2 cold crank condition

I would like to use the above design recommended in the LTC4366-2 datasheet. The is a problem on cold crank 12V systems, that can drop to 4-6V during staring of the engine. Can I use a capacitor like ...
6
votes
1answer
168 views

UL Clamping Voltage Ratings on Surge Protectors

I have been looking for some new surge protectors for my devices, and I am having trouble understanding the meaning of the voltage clamping ratings on many surge protectors. It seems that all of the ...
0
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1answer
107 views

Calculating energy of transient/surge handled by metal oxide varistors (MOV) or surge suppressors?

As I get to know more about the MOV operation, there are more things needed to understand. My MOV (V420La20AP) has Varistor voltage of 680 Vrms (10%) at 1 mA, and maximum clamping voltage of 1120 V ...
0
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0answers
53 views

Choosing Varistors for 61000-4-5

I would like to know what kind of surface mount varistor I need to choose to pass IEC 61000-4-5 Class II which is 1kV for a low voltage (24V dc) circuit When you want to choose Varistors or MOV you ...
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votes
1answer
136 views

What is Metal Oxide Varistor (MOV), meaning of its specification and how it protects circuit from over-voltages?

Hello, I have a circuit in which a voltage source is connected to some sort of RC Load. To protect this circuit , there is an Metal Oxide Varistor (MYN15-681K). The Pics of circuit and datasheet ...
2
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0answers
68 views

High power / high current clamping circuit

I am looking for ideas on how to clamp high energy surges in the input of a high current / high power system. The input to the system is 24V. During steady state, the system sources 85A of current ...
0
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0answers
56 views

Surge Protection for Optocoupler

Resistor Specification Edited: 24July18 Does the TVS + Zener diode provide adequate surge protection to the opto from voltage spikes and indirect lightning hits? The resistors are smd type with ...
2
votes
2answers
252 views

Auto turn off switch during power outage

In my area power outages are a daily routine. And power surges, which occur when the electricity comes back, makes it even worse. To avoid damage of the electronic devices we try to unplug them ...
0
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0answers
25 views

Power Outages and Surges

I live in South Africa where we experience frequent power outages due to so-called "loadshedding". With this, there have been numerous cases of damage to appliances due to surges, usually when power ...
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0answers
12 views

Deriving a Voltage Dependent Expression for Surge Arrester Characteristics

I'm performing a transient voltage study, and I'd like to be able to see the resulting waveform with the addition of a surge arrester installed. Given manufacturer data (V-I characteristic curve), is ...
0
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2answers
106 views

What kind of protection do these Ethernet “surge protection” diodes provide?

I was considering a network run outside of my home, and purchased a super-cheap "Ethernet Lightning Protector" because there was little to lose, and I wanted to understand its workings. Below you can ...
2
votes
1answer
60 views

Can someone explain the working of this Surge Suppression Circuit

This is an old circuit which is still being used. I am curious to understand that if 600 VAC is applied to AC side of the three phase rectifier which has diodes, and on the DC output side of the ...
0
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2answers
76 views

Automatic cut mains power on a thunderstorm

I am a software engineer with only a basic experience with electric/electronic engineering. I live in a rural area subject to thunderstorms, my house is the end of the line from street poles. It's ...
0
votes
0answers
32 views

TVS Diode Response

I am trying to understand what would the response of the TVS diode be when I will apply +5V and -5V across the device. From what I understand is that when I will apply +5V and Ground across Pin1 and ...
3
votes
3answers
183 views

History of ESD protection

These days you can't read anything about electronics without hearing about the dire consequences of omitting ESD protection from your designs. It seems this wasn't always the case. If you look at ...
1
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2answers
209 views

overshoot and undershoot on 3 volt pulse

i am interfacing a system, this system output signal of 200ns digital pulse with repetition time of every 3ms. Ideal voltage of signal would be 0v to 3.3V but signal coming from system have high ...
2
votes
2answers
268 views

Lightning protection for underground loudspeaker wires

I am tasked with running a loudspeaker to a remote building. The total run length is around 275 feet, with the outdoor portion being around 165 feet. The cable is Cat5e 24awg unshielded, silicone ...
4
votes
2answers
1k views

How to choose the right Metal Oxide Varistor (MOV)

I would like to protect the input of a transformer against high voltage surges but I don't understand how I have to proceed to choose the right MOV despite what I read so far about them. Below is how ...
3
votes
3answers
107 views

How to protect againt surges if working and maximum voltage are too close

I have a circuit that I want to protect against surges and eventual peaks (e.g. indirect lightning surges) and I was thinking about TVS diodes or MOV. The situation is: -My circuit input is 48V that ...
1
vote
1answer
204 views

Triac misfires because of noise from inductive loads

The product is a wifi enabled smart switching device. One device has 4 different channel for four different appliances to be connected to the product. Each channel has a pair of optocoupler and triac ...
0
votes
2answers
51 views

What stats to look for in a surge protector, how to compare them and what are recommended some European surge protector brands (and models)? [closed]

I read that joule rating is more like the lifespan of a surge protector, some don't even list them, for an example the german brand Brennenstuhl only lists their surge protectors with leak through amp ...
10
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2answers
486 views

Relay protection when proper TVS at load cannot be implemented

I'm currently developing a product which has a simple SPDT relay that can be controlled by an operator. To the end-user, only the common, normally open and normally closed contacts are available. The ...
2
votes
1answer
273 views

Pc power supply Ac in rush current overloading inverter

I have a PC consuming 400 watts hooked up to an 220 VAC automatic backup 1500VA 12V dc inverter since AC grid line is not 24/7 in my country. The main problem is that sometimes when the AC power goes ...
0
votes
1answer
77 views

How to UPS-protect this “dual source” setup? [closed]

I'm analyzing how to best protect a setup comprised of a NAS/Router/Wimax from power surges. A very simple diagram is this: When I write "dual source" (term which I just invented) I mean that the ...
0
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0answers
29 views

Water pump, PSU and surges

I've got a home-built watercooler that I've been using for more than a decade on my personal PC. The unit has a single switch for the AC mains (120V 60hz) that splits to power both the AC waterpump, ...
8
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2answers
691 views

Connecting TVS before or behind Ethernet transformer?

I looked at several designs and recomendations. Why do TVS diodes sometimes connect before and behind transformer? What are the pros and cons of connecting before or behind?
0
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1answer
106 views

Distance between surge arrester [closed]

I'm installing surge arrester to protect a server room full of machines using the following page as a guide http://engineering.electrical-equipment.org/electrical-distribution/how-choose-surge-...
4
votes
3answers
375 views

ESD protection diode circuit confusion

In the following circuit, my understanding is that when there is a spike or rise in the data line higher than Vcc, the top diode conducts and the voltage flows into the path to protect the downstream ...
6
votes
1answer
362 views

Snubber Capacitor Voltage Rating in the Real World

What are voltage ratings for the capacitors inside the common off the shelf ac snubber networks, such as 0.1uF + 100 Ohm ? It would seem that larger inductive loads can easily drive the capacitor ...
0
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0answers
105 views

Blown varistor after connecting UPS?

I have a pellet burning stove and the manufacturer provides for two options for battery backups. One is an inverter and deep cycle battery that can run the device for a few hours, the other is a UPS ...
2
votes
1answer
281 views

TVS Diodes for Audio?

Usually audio inputs use protection diodes that shunt into the power supply rails of the device they're protecting. But is this really necessary? Why are TVS diodes not used here? Yes, some are high ...
3
votes
2answers
235 views

12V Relay Voltage Surge on contact close

I'm designing a pcb relay circuit to switch on/off power to an inductive load on a 12V line. I'm using an SPST-NO relay (omron relay) to switch the circuit open and closed, and I'm having trouble ...
1
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2answers
343 views

Do I need to connect capacitor across MOV?

I was designing some circuit for powering my module, where I need to provide protection against high voltage AC. I found one reference from Microchip MCP39F511 where they have used MOV which is ...
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0answers
110 views

LT4363 High surge stopper shutdown at start up

I was asked to protect a DC/DC Buck converter against overvoltage and overcurrent event. During my research, I found the LT4363-2 component from Linear Technology that is defined as a High Voltage ...
0
votes
1answer
157 views

How to combine and protect two 12V automotive signals into one?

In the below circuit, the DC component (6V) of a bridged car head unit speaker wire turns on a LM53601 buck converter. The LM53601 accepts voltages up to 42V. The +12V input into Q2 is protected to ...
3
votes
1answer
498 views

Diode TVS selection for 36V circuit

I am wondering what is the criteria for selecting diodes TVS, for example my circuit runs at 36V and I want protect my circuit from spikes But I am little confused about the Breakdown Voltage (VBR) ...