Why has DIYNOT got a electrics forum?

[Big_Spark]

Slippery, you are of course correct, I just re-read my post and that comment is incorrect when speacking of purely resistive circuits. The only way to increase or decrease the current in resistive circuits is to alter the resistance OR alter the voltage, but an increase of voltage will result in an increase in current..

ie: Example resistance of 11.75Ohms

At 230V this is 19.57A and produces 4501W of energy

At 400V it is 34.04A and produces 13.6kW of energy

Halving the voltage to 115V will cause a decrease in current drawn to 9.78A.

When I made the post I was also making posts about a constant power circuit, due to being tired at the time I think I must have mixed the two topics and dropped the ball....I had been awake for 17 hours and was also trying to price a job as well as making the posts

 

[oilman]

.......................

................Halving the voltage to 115V will cause a decrease in current drawn to 9.78A.

When I made the post I was also making posts about a constant power circuit, due to being tired at the time I think I must have mixed the two topics and dropped the ball....I had been awake for 17 hours and was also trying to price a job as well as making the posts

Oh at last, and of course, not only were you tired etc, but driving a military transport under fire while accomodating a broom handle in the rear end to sweep the floor. Dropped the ball? That might wash with your poor unfortunate customers, but I would trust you as far as I could throw an elephant.

 

[jbonding]

What the f$%K u all going on about in here. This is supposed to be general chat, not degree level electricity with added abuse go and have a lie down for gods sake

What kind of degree did you take pickles, if you think that i=V/R is so difficult?

A law degree

I certainly have great respect for that achievement, but are you serious when you say that I=V/R is too technical?

In case the answer is yes, the favourite analogy is a hosepipe....

The pressure of water at one end of the pipe is analogous to the potential difference, measured in Volts.
The resistance of the hosepipe to water that is otherwise willing to flow inside it, is analogous to, well, er, resistance (measured in Ohms).
The flow of water along the hosepipe, when you open the tap, is analogous to current, measured in Amps.

So, if you have a long hosepipe, and a short one, and the two are identical bore and constriction, it follows that the resistance of the longer one is greater, and the effect on the flow is to reduce it.

This is basically it - the flow is determine by the pressure and the resistance. In a simple electrical conductor (e.g. a wire), the flow of current (Amps) is determined by the 'pressure' (potential difference, in Volts) between one end of the conductor and the other, and the electrical resistance of the wire.

Thanks to various scientists over the decades, we have a means of calculating the current, without measuring it, if we know the Volts and the Ohms for a given conductor.

I (current) = V (Volts) divided by R (resistance)

Lo and behold, I=V/R.

BTW, I is used for current because C got reserved for Coulombs, which is a measurement of charge (related to current, but I'm heading off track).

If you were winding us up, then you probably regard my explanation as patronising, in which case please accept my apologies - I'm just trying to help.

It isn't now you have explained it. I was slightly over egging the cake out of frustration However that this thread from a non techies point of view is getting a bit tedious due to

a) everyone takin part having had their sense of humour bypassed for the occassion

b) It being basically unintelligible to a lay person

c) It not reflecting well on electricians, because if you can't agree amongst yourselves how can any one else rely on you. This rubs salt in the part P wound, because we have to get you lot in to at least check things we have been doing as competent DIYer's for years without any problems eg cables catching fire, gruesome deaths or the whole street shorting out. My experience of domestic electrics is that there are basic rules that have to be learnt and followed to the letter for safetys sake but that it is not rocket science There are many sources of good info
in books and such like and it is perfectly possible to do work that is as safe and compliant. Some of the strangest things I have seen have undoubtedly been done by professionals

d) it actually confirms the original gripe that started the thread which I agree with that it's hard to get straight advice in the electrics forum. You tend to get nothing, snide comments, over academic advice or suggestions that you should use an electrician. You need to give a straight answer or not answer at all. It is a common fault of people with technical knowledge that they are bad at explaning themselves or helping others, I should know, and it is on regular display in electrics. the other forums here generally are not like that and some of the subjects can be just as technical

ps I am not having a pop at anyone it's just that as a group your wires are hanging out (no pun intended)

well said i couldnt agree more, softus you didnt understand what i said or meant this is it, but written in the way i thought.

 

[Softus]

well said i couldnt agree more, softus you didnt understand what i said or meant this is it, but written in the way i thought.

Fair play / no problem / all's well that ends well / thanks

 

[Softus]

Slippery, you are of course correct, I just re-read my post and that comment is incorrect when speacking of purely resistive circuits. The only way to increase or decrease the current in resistive circuits is to alter the resistance OR alter the voltage, but an increase of voltage will result in an increase in current..
.
.
.
When I made the post I was also making posts about a constant power circuit, due to being tired at the time I think I must have mixed the two topics and dropped the ball....I had been awake for 17 hours and was also trying to price a job as well as making the posts

OK - understood - we all get tired.

What does this mean, though, to your post about total load current? Was a slip of the tired mind too?

 

[Big_Spark]

Softus..glad that got cleared up..I did feel a bit foolish when I read my post..and thought.."hang on..where the Eff was my brain when I wrote that load of tosh..."

Regarding the use of the term Full load current..yes I could equally simply say the Current in the circuit, but technically it is not electrically correct, even if intrinsically it is...

The problem is the type of circuit your connected too, if it is an inductive load, when you bridge the gap there will actually be a peak current flow as the inductive load powers up, which will then drop to normal run current. The type of circuit I am thinking of would contain things like motors or transformers etc, so I use the term FULL LOAD CURRENT to differentiate between other currents in the system, including eddy currents, harmonics etc..

Hope this clarifies that.

 

[Softus]

Softus..glad that got cleared up..I did feel a bit foolish when I read my post..and thought.."hang on..where the Eff was my brain when I wrote that load of tosh..."

Understood - hope you can see why many of us were questioning your sanity at the time....

Regarding the use of the term Full load current..yes I could equally simply say the Current in the circuit, but technically it is not electrically correct, even if intrinsically it is...

Also understood - thanks.

The problem is the type of circuit your connected too, if it is an inductive load, when you bridge the gap there will actually be a peak current flow as the inductive load powers up, which will then drop to normal run current. The type of circuit I am thinking of would contain things like motors or transformers etc, so I use the term FULL LOAD CURRENT to differentiate between other currents in the system, including eddy currents, harmonics etc..

Hope this clarifies that.

Yup - that's clear enough. Would it also be true to say that, in the average run-of-the-mill single phase domestic scenario, with the biggest motor being the one in the washing machine, that we could discount these effects for the purpose of determining the current through the person who is bridging the gap?

 

[Big_Spark]

Good point softus and very true.

Regarding my sanity..that's been in question since I was born 39 years ago!!

Seriously, I think this proves to me that I need to take a few days off..I'm now on day 109 of working without a break, the last couple of weeks I have been working about 12 hours, with 2 hours travel (total) plus paperwork when at home for 4 to 5 hours..to be honest I am surprised any of my posts have any clarity to them..

I started at 6am today, but left at 4:30pm today..ran out of materials for one part of the job so called it a day...no paperwork today, I am simply going to have an early night and good sleep...perhaps I can then make sense!!

 

[Moz]

YAWN !!! LOL

 

[jbonding]

Good point softus and very true.

Regarding my sanity..that's been in question since I was born 39 years ago!!

Seriously, I think this proves to me that I need to take a few days off..I'm now on day 109 of working without a break, the last couple of weeks I have been working about 12 hours, with 2 hours travel (total) plus paperwork when at home for 4 to 5 hours..to be honest I am surprised any of my posts have any clarity to them..

I started at 6am today, but left at 4:30pm today..ran out of materials for one part of the job so called it a day...no paperwork today, I am simply going to have an early night and good sleep...perhaps I can then make sense!!

you must be loaded and if your not?