ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
This anti-theist is priceless!!!
by djk. 11/14/18 07:19 AM
Single phase and what you call it.
by dsk. 11/12/18 11:10 AM
220/230/240V 60Hz Systems
by Albert. 11/07/18 12:48 AM
Black & Decker Recalls Hammer Drills
by Admin. 11/01/18 07:22 PM
New in the Gallery:
What is this for?
Plug terminals
Who's Online Now
0 registered members (), 9 guests, and 23 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
RMS question? #126973
03/22/01 06:51 AM
03/22/01 06:51 AM
O
old Appy  Offline OP
Member
Joined: Mar 2001
Posts: 118
Auckland, New Zealand
Hi again,
we use 230 volts RMS or 325 volts p to p we use 0.707 to find 230 volts from 325 this i know..so the equation to find 0.707 is R M S? how does this equate out longhand?

Tools for Electricians:
Re: RMS question? #126974
03/22/01 12:31 PM
03/22/01 12:31 PM
J
John-Tx  Offline
Junior Member
Joined: Mar 2001
Posts: 8
Austin, Texas
Hi everyone. I'm not an electrician; I'm an electronics tech in Austin, Tx. I hope nobody minds me posting here, even if I do work on the other side of the disconnect (I'm also a homeowner, but at least I know the difference between a codebook and a Sunset Book.)

Appy, RMS is the equivalent DC voltage for an AC supply. I think you're asking why RMS equals .707 peak voltage. This is because pure AC power is considered to be a sine wave. If you average the absolute voltage across one cycle, it will be the peak voltage multiplied by the sine of 45 degrees, which is .707. This makes sense as this is also the voltage at an instant halfway in time between zero volts and a peak.

It might be worth noting that RMS doesn't equal .707 peak for all AC signals. For example an AC square wave, where voltage jumps immediately between positive and negative peak voltage, would have an RMS voltage equal to the peak voltage. It's just that electric power is pretty much kept to a clean sine wave.

Here's a page that explains it pretty well (probably better than I could.) In any case, I hope I helped out with this.

Re: RMS question? #126975
03/22/01 01:10 PM
03/22/01 01:10 PM
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,903
NY, USA
John,

One of the reasons for this separate Theory section was to promote more interaction between those involved in the 'Practical' Electrical applications (Electricians) and those involved in Theory and Electronics (such as yourself). So, to answer your question, you're not only Welcome, We've been kinda waiting for you! [Linked Image]

Feel Free to jump into something else or ask us something.

Do you know where all the 'lost' Electrons go? [Linked Image]

Bill


[This message has been edited by Bill Addiss (edited 03-22-2001).]

Re: RMS question? #126976
03/22/01 06:45 PM
03/22/01 06:45 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,371
Hi John,
neat link, very interactive with those "wave sounds".

Welcome aboard!

[Linked Image]


[This message has been edited by sparky (edited 03-22-2001).]

Re: RMS question? #126977
03/23/01 12:34 AM
03/23/01 12:34 AM
O
old Appy  Offline OP
Member
Joined: Mar 2001
Posts: 118
Auckland, New Zealand
Thanks John,
I appreciate your help and great link

Re: RMS question? #126978
03/26/01 02:09 PM
03/26/01 02:09 PM
J
John-Tx  Offline
Junior Member
Joined: Mar 2001
Posts: 8
Austin, Texas
Sorry for this being a late response. I work nights and didn't have a chance to reply until now. I'm glad that I could help, and I'll try to join in on the other theory secions.

Right, Sparky, all we're doing in an electrical circuit is pushing electrons around a loop. In an AC circuit, were pushing them back and forth. I think it takes a subatomic physicist to destroy them.

That said, can you tell me how to put the smoke back into shorted components? It would save us a lot of time at work. [Linked Image]


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Radar
Radar
Los Angeles, CA
Posts: 349
Joined: April 2004
Show All Member Profiles 
Top Posters(30 Days)
Admin 8
dsk 3
Popular Topics(Views)
251,431 Are you busy
188,648 Re: Forum
178,353 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.021s Queries: 14 (0.004s) Memory: 0.9770 MB (Peak: 1.1237 MB) Zlib enabled. Server Time: 2018-11-14 16:16:48 UTC