Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [dielectric-breakdown]

Use this tag when the topic concerns a material which is designed to separate conductors is pushed beyond its voltage limits then allows current to flow. This can be in reference to capacitors or coax cable, among other things.

Use this tag when the topic concerns a material which is designed to separate conductors is pushed beyond its voltage limits then allows current to flow. This can be in reference to capacitors or coax cable, among other things.

When the subject is capacitors it is fairly easy to know the voltage limit.

However, for Coax Cables it takes a certain amount of effort to look up the specifications for the exact type of coax used.

This article shows an example of how to know Vmax for various types of coax:

Coaxial Cable Specifications

43 questions
26
votes
6 answers

Why do high-voltage transformers need oil?

Someone told me that high-voltage transformers need oil because it prevents arcing. However, in terms of dielectric breakdown, isn't air the strongest? I remember from classes in college that as the dielectric constant increases, the breakdown…
PJazz
  • 857
  • 9
  • 14
7
votes
2 answers

Estimate capacitor parameters

I am thinking of making a capacitor, just for fun/for studying purposes. And I thought of the following exercise. In my local store, there exists rolls of polyethylene food film and aluminium foil. Theoretically, I can take a couple of both, and put…
xakepp35
  • 395
  • 1
  • 14
6
votes
1 answer

What determines the voltage rating of a cable?

I'm trying to figure out the maximum voltage of some cables in a vacuum system I've inherited, and I'm confused by the DC voltage ratings given by this supplier as they step from the 3 kV to 10 kV rated cables. In each case the difference between…
llama
  • 548
  • 3
  • 9
6
votes
5 answers

Why are arcs so hazardous compared to standard current flow?

I know that electric arcs are dangerous as they can start fires, cause explosions, melted insulation, etc. and they are generally undesirable. However, I am a bit confused as to why. Arcs generate heat, but shouldn't normal current flow also…
Agniva Chaudhuri
  • 109
  • 7
3
votes
1 answer

Spark gap minimum breakdown voltage vs air gap

I'm trying to calculate the minimum voltage needed create a spark across 2 electrodes (needle shaped) in open air at normal ambient pressure. Usually, I would use the figure of 3000V /mm as the breakdown for air, which gives these figures: 300V for…
Anchovy
  • 303
  • 1
  • 6
3
votes
1 answer

Dielectric strength withstand vs impulse withstand

In ISO 6469-3 two tests are defined. Dielectric strength test: Extended period of time (1min) at a set voltage over insulation barriers (simplified). Usually a ramp up of the voltage is allowed. Impulse withstand: A pulse at a higher voltage than…
LukasL
  • 128
  • 6
3
votes
2 answers

How come distilled water hasn't replaced transformer oil as a high voltage insulator?

I've noticed that distilled water has an extremely high dielectric straight (65-70 MV/m). With that considered, how come it isn't used in the place of transformer oil for 10-20 kV applications where the structure might not need to last multiple…
user154046
3
votes
1 answer

Dielectric (HI-Pot Test) Failure on Ethernet Port

We have failure on Dielectric test between Power wire to Ethernet Port. Failure was observed near 1.7kV. After test Ethernet port was damaged (Phy chip). See attached Case 1 :- Where we apply High voltage between Power to Ethernet terminal. (see…
Bharav
  • 722
  • 2
  • 7
  • 21
3
votes
3 answers

High voltage dielectric breakdown & layering insulators

I’m going to use 230 kV as the reference voltage for the example below; I know if I put a piece of metal too close to a 230 kV source it will breakdown the air and jump to the piece of metal causing a visible spark, even if the piece of metal is…
Nick
  • 31
  • 5
3
votes
2 answers

HIPOT testing and Y capacitors

The electric strength test OR dielectric withstand test OR HIPOT test voltage level as specified in EN 60730 standard works out to be 2860VAC for a class II radio product I am developing. The PCB has an isolated switched mode power supply with a…
Sam
  • 31
  • 1
  • 3
2
votes
1 answer

How can fumes make this electrical arc travel so far in distance to the other side?

Why is the arc travelling so far, and what kind of vapor conducts electrons so well? https://www.youtube.com/watch?v=PXiOQCRiSp0
bandybabboon
  • 887
  • 2
  • 11
  • 28
2
votes
2 answers

What is the best way to transmit 1 kW (power supply) to a tethered drone so that the cable thickness and weight is minimized?

I am delivering 1 kW power to a tethered drone. To minimize the wire weight and maximize maneuverability, I would like to keep the wire as thin and lightweight as possible. The motors on my drone have a peak current of 70 A. However, a wire capable…
Pragy Agarwal
  • 121
  • 2
2
votes
1 answer

Insulation safety ratings (working and withstand voltage) of fiber optics cables

I'm trying to build a high voltage optocoupler to implement galvanic isolation between a high voltage supply and its control signals. Since the working voltage is several kilovolts, it's beyond the ratings of all isolation ICs. Thus, the plan is to…
比尔盖子
  • 6,064
  • 2
  • 24
  • 51
2
votes
1 answer

PCB layers as isolation

What voltage can I expect primitive PCB (2 copper layers, one on each side), to hold between one and another layer? I assume removing copper at edges should make the edge path longer, so I am mostly interested in through-PCB breakdown. I’m…
Surprised Seagull
  • 406
  • 2
  • 6
2
votes
1 answer

Dielectric break down of stacked glass layers

We have a capacitive touch panel with 1 mm thick cover glass. Currently it is failing at 15kV ESD. I am assuming that dielectric breakdown of the glass occurred and the touch driver is exposed to higher ESD and failed. To increase and finalize…
ChandanN
  • 153
  • 5
1
2 3