Can a 220v transformer store electiric charge?

  • Thread starter Thread starter chrisalviola
  • Start date Start date
  • Tags Tags
    Charge Transformer
Click For Summary

Discussion Overview

The discussion revolves around the phenomenon of electric shock experienced after turning off a 220v transformer. Participants explore the reasons behind the potential storage of electric charge in transformers, comparing it to capacitors and discussing related electrical properties.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant reports receiving an electric shock from the primary windings of a transformer after it was turned off, questioning how this could occur.
  • Another participant suggests that the shock may be due to charge stored in the parasitic capacitance of the secondary windings and inquires about measuring the secondary capacitance.
  • A different participant raises the possibility that the case of the transformer may not be grounded and suggests that the individual could have built up charge through movement.
  • It is noted that transformer windings possess capacitance to the frame and to each other, which could contribute to charge retention.
  • A participant shares a measurement of capacitance from a small transformer, indicating that while it is typically not a problem in normal use, it can still result in a small shock.

Areas of Agreement / Disagreement

Participants express various hypotheses regarding the cause of the electric shock, with no consensus reached on a singular explanation. Multiple competing views regarding charge storage and safety are present.

Contextual Notes

There are unresolved aspects regarding the specific conditions under which the shock occurred, including grounding status and the exact capacitance measurements of the transformer in question.

chrisalviola
Messages
80
Reaction score
0
i turn off the transformer i assembled its from a 220v power source i touched the primary windings and surprisingly it gave an electric shock. i never know this things store charges like capacitors, how does this happen? any explanations?
 
Engineering news on Phys.org
chrisalviola said:
i turn off the transformer i assembled its from a 220v power source i touched the primary windings and surprisingly it gave an electric shock. i never know this things store charges like capacitors, how does this happen? any explanations?

That's a bit weird, but maybe the charge was stored in the parasitic capacitance of the secondary windings. With the transformer fully discharged and not connected to anything on the primary, what do you measure the secondary capacitance to be?
 
Is the case grounded? You might've built up some charge walking around, bouncing your leg, etc.
 
Transformer windings have capacitance to the frame and usually capacitance to each other because they are just two pieces of metal separated by a dielectric.

Large mains transformers tested at high DC voltages have to be discharged before they are safe as they can hold lethal charges for many days otherwise.

I just tested a small 250 volt transformer primary and it had 150 pF capacitance to the transformer frame. So, it isn't likely to be a problem in normal use, but you could still get a small zap off it.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
2
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
10
Views
3K
Replies
12
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 27 ·
Replies
27
Views
4K
Replies
6
Views
4K
Replies
5
Views
3K