Questions tagged [mov]
Metal Oxide Varistor - A circuit protection component which clamps voltage waveforms above some value that the particular device was designed to protect for. It is a sacrificial device and absorbs energy and accumulates damage over it's useful life, eventually failing. They come in different voltage and energy absorbtion capabilities.
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Why did all my surge protectors smoke when my home became ungrounded?
I live in North America and the ground/neutral wire between the utility pole and my home was severed. When this occurred, all my surge protectors fried.
Why would this happen?
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AC Line Filter Design Review: Layout or MOV Weaknesses in Surge Protection?
I'm building an AC line filter to protect downstream DC supplies (like a Mean Well DRC-40) from grid surges, including recloser spikes and storm-induced transients. It's intended for rural use where ...
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Lightning protection for landscape lighting
I've built a custom landscape lighting system. It consists of a number of "strings" of series-connected LED luminaires, each controlled by a current source (LT3081 regulator). The voltage on ...
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How to protect 240V system from Low surge of 0.5kV
Have an issue with our system, which operates on 110V-240V AC, when subjected to low-level surges of 0.5kV line-to-line and 1kV line-to-line. Below are more information:
Using RAC10E-05SK/277 AC/DC ...
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AC mains SPD device using TVS diode + MOV
For the 2nd time in 2 years I have had the same logic board inside my hybrid solar inverter get zapped from an indirect lightning strike maybe half a mile away (all other components 100% fine). After ...
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MOV / SPD rating
Looking for guidance on how Type 1 & 2 "whole home" residential surge protection device (SPD) published ratings are commonly figured. Let's say that a SPD has 5 MOVs as per circuit below....
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Sustained HV protection
I am designing a device which can be exposed to sustained overvoltage of 6kV for 1 min. I need to provide immunity to my device in such a case. Issue lies herein the fact that the device uses a zener ...
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Do I need a MOV in front of AC/DC supply
I am working on unit that needs to pass IEC6100-4-5, see table below:
I have an AC to DC power supply, 100-230VAC, 50/60Hz, 5V/6A.
AC/DC power supply can pass these tests without a MOV mounted in ...
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Calculating power and energy of a surge waveform
As far as I know, to determine if a Surge Protection Device (SPD) is suitable for a specific scenario, it must be capable of handling the energy of the surge for the duration of that surge.
I want to ...
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Why are MOVs rated for mains voltages chosen for earth-to-signal protection in PoE PSE applications, as recommended in TI's SLUA818?
I wondered why TI in their application note SLUA818 says MOVs rated for mains voltages must be used between signals and earth:
Therefore, based on the above, the MOV used for the earthed PSE must ...
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Varistor and Fuse Failures in Control Panel During Power Failures - Seeking Advice on Enhanced Protection
Question:
I'm facing a recurring issue with our control panels used for firefighting and fire alarm systems. During power failures, the varistors, responsible for overvoltage and undervoltage ...
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Why too many MOVs used in surge protectors? [closed]
I got this photo only for reference, and have no idea about the circuit:
but why in this surge protector too many MOVs are used, I mean normally the lowest impedance MOV would take the most surge ...
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Using MOV to protect device for heater element
I have a heater element that is controlled by a solid state relay from main power. I know it is customary to place a MOV in parallel when switching inductive loads to clamp the voltage to prevent ...
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Handling higher clamping voltage of IsoMOV - MOV/GDT Hybrid
I'm working on an ac mains control circuit and came across IsoMOV a new hybrid MOV/GDT for surge suppression. This appears to be a straightforward replacement for a standard TPMOV with additional ...
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How to spec a MOV resistor
I want to add a resistor before my MOV. The largest surge I will have will be 3kV.
I came across this datasheet.
If the most voltage my load can handle is 1kV surge, what will the resistor value be?
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LTspice MOV tutorial/help
I am looking at the availability of the pictured component on LTspice and cannot find it when I type it in the component library search. Please let me know the component symbol name or if I need to ...
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Can this circuit limit power surges?
This circuit I had created based on MOV and a relay, it principle is: if a surge comes the MOV would get activated and should turn the relay thus the surge should be redirected.
Notes:
Input is ...
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Problems with MOV (Metal Oxide Varistor) simulation in LTspice
I recently ask a question relating this topic because I was having problems with the spice models supplied by the manufacturers wich consists of a logarithmic power law:
The problem was of the type &...
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Location of Fuse and MOV
I have an AC module where the input is AC mains.
I am also using 2 AC-DC modules. AC-DC module 1 5V output & AC-DC module 2 12V output
Both these AC-DC modules requires fuses. I also want to place ...
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LTspice error with varistor model and impulse current test
I'm trying to use the TDK varistor spice models in LTspice and there are some things that don't add up. In the figure below you can see the actual equivalent circuit of the TDK model. I know that I ...
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MOV parameters understanding and capacitance
I want to add a MOV to the input of my circuit. I came across the following MOV.
The specs I require will be the following:
Max voltage 300V AC rms
Surge voltage 1.4kV
Response time 8/20us
I have ...
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Can MOVs draw lots of current at low voltage?
This circuit should open my fuse in case of an intentional overvoltage attack.
(think as someone intentionally plugging 100V to the 24V input)
Thing is I can't afford to have more than 45V to the rest ...
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Can electricity distribution transformers increase lightning surge current from 30 kA to 1500 kA?
I read somewhere that an average lightning strike is about 30 kiloamperes and lasts for a duration of 30 microseconds (but it may consist of number of sub-flashes so the total duration may be 0.2 ...
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How to protect a high-voltage output stage from very high transients
Usually in electronics, one can use MOV or TVS diodes to get rid of voltage transients. That's because most applications run at a voltage of 500 V or less.
But assume I want to protect the output ...
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Identifying a MOV
I have a buddy with a St. Croix Lancaster corn stove with a control board in it that was taken out by a malfunctioning generator (the pellet stove was not even turned on, but like most semi-modern ...
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How do MOVs work for surge protection?
I'm trying to understand how MOVs operate but all my online reading is calling my understanding of electronics into question.
The above diagram seems to be the typical layout of a MOV used for surge ...
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Right wiring for 3 phase 4 wire surge protection devices
I am looking for commercially available SPDs and came across two different options:
Option - 1: Return path is earth and there is an MOV on all the lines. Schematic would look like this:
Option - 2: ...
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Use of MOVs without fuse?
I understand the MOVs become almost short-circuit when input voltage across them exceed a threshold.
But how does this protect the circuit behind the MOVs? Suppose the input power supply voltage ...
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Does a relay with a capacitive load still require a MOV?
I was planning to install this Metal-Oxide Varistor (MOV) across a relay switch. But after I read about the use of MOVs for switches here, it seems to me that MOVs are useful only if the load is ...
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Confused about back EMF protection in maglock circuit
Straight upfront...electrical engineering is not my forte. However, I am trying to help a client with a particular issue and I'm hoping this community can provide some invaluable insight.
They have a ...
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Is it possible to use an MOV instead of a flyback diode in a pulse circuit?
I am working on a small high-voltage pulse circuit to protect my animals. I have a question about the flyback diode D2 to protect the SCR.
The flyback diode seems to waste a lot of energy between ...
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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. ...
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Can placing MOVs on a 240 V input ever be a bad thing?
The power supply of my home lighting keeps failing. So far I have had ten identical power supplies fail. Upon inspection the thing that is always damaged is the electrolytic capacitor after the bridge ...
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Triac driving motor with limit switch, needs protection?
I'm trying to drive a bunch of motorized ball valves from an ESP32.
These valves have a 230V AC motor with one common wire, and two wires to set direction (open/close). When powered between common and ...
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How to add surge protection and over voltage protection for a smart switch SMPS
I am making a smart switch for toggling appliances with a 10 A relay using esp8266 as my MCU.
I am using an isolated 3 W (5 V, 600 mA) SMPS. I have seen in some specifications about 2.5 kV surge ...
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MOV failed due to lighting or OV on power line Feeder control
we have a filed failure of our product which is feeder controller as shown in below image. It installed in metal box. we have tested our feeder stand alone at 15KV surge and it compliance with 15KV. ...
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Regarding connecting MOV and SMPS in parallel for electrical meter
We are working on development of a 3 phase electrical metering circuitry. All the 3 phases are connected to metering IC using resistor divider circuitry for voltage measurement (between phase and ...
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gdt and mov surge protection
greetings fellow engineers, i came by to ask you for help, i'm building a circuit that needs to be as resistant to surges as possible. I did my research, and make to this circuit: as it is supply by ...
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Help in assessing the input mains circuit integrity
I've been working on designing a (220-380 VAC) 3/4 wire phase energy meter and in terms of metrology operation, things were working very well quite similar in terms of metrology if compared to a ...
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What's the effect of parallel resistor and MOV?
What is the effect of connecting a metal oxide varistor in parallel with a resistor? Does the resistor make the varistor more responsive in case of a surge?
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Can a MOV properly discharge a X-Capacitor?
I created an AC-DC SMPS with a EMI filter that consists of a X-Capacitor and Common-Mode Choke. IEC 62368-1 requires that capacitors be discharged below ES1 (60V) within 2s of being disconnected. As ...
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Digital input over voltage protection solution - varistor or TVS
I have to select the best safe solution to protect a 5V input.
Below are four solutions that I have designed to protect my 5V input against over voltage using a varistor and a TVS.
Different ...
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What is the 0V reference for MOV's input protection on power supply?
In some application notes for MOVs I see example usage in power supply design where each input line (N, L) from the mains are protected with a MOV to a ground voltage reference (as well as a ...
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Help identifying a varistor (on a shredder PCB)?
I am trying to identify what I think is a varistor. The markings are : "9 / MVG" and "10K431".
I think "10" is the diameter, "K" is the tolerance and "431&...
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Replacement for TVR 10561 varistor
I am trying to repair the power supply of my PS4. It looks like the fuse has blown out with the TVR 10561 varistor. I can't find this varistor online and I am looking for a replacement.
The TVR 10561 ...
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Metal Oxide Varistor connection
How do I select the MOV for a multiple operating voltages. Consider the diagram below, when switch is in position 2-1 and 5-4 (both primary winding are connected in series), I can apply an input ...
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How to place MOV when you have a center tapped transformer 127V 220V
I am building a circuit that gets power from AC. I have a center tapped 220V transformer, so I added a switch for 220V or 110V (the three wire sockets)
I added two MOVs, one S20K230 for 220V and a ...
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What causes a varistor to have low resistance when connected to a board?
I was inspecting the control board on a non functioning opener motor, there are no visible blown out components. No skid marks. I went to testing conductivity on the fuse component, good across there. ...
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Metal Oxide Varistor Identification / Replacement? Component marking IOE241 99P
Could anyone identify the component shown in the image? It is marked 'IOE241 99P'. It is ~12mm in diameter. I believe it is an MOV. The image shows the location on the Power PCB it was removed from. ...
