×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

How do you determine Peak current in Sine Wave

How do you determine Peak current in Sine Wave

How do you determine Peak current in Sine Wave

(OP)
I always heard that you multiply 2.2 by the RMS value but how is this derived?

thanks,
mark

RE: How do you determine Peak current in Sine Wave

(OP)
I meant to say how do you determine peak to peak, I've been told to mult rms by 2.3.  where does 2.3 come from?

thanks,
Drax

RE: How do you determine Peak current in Sine Wave

RMS means root mean squared, i.e. you multiply the RMS value by the square-root of 2, which is 1.41.


RE: How do you determine Peak current in Sine Wave

If you mean, by "peak to peak" the maximum instantaneous current at two peaks in a single cycle sinewave, then it is 2 times the square root of 2.  Or in otherwords, 2.8284.

RE: How do you determine Peak current in Sine Wave

Ooops, I didn't get the second sentence finished.  It should say -

Or in otherwords, 2.8284 times the RMS current value.

RE: How do you determine Peak current in Sine Wave

(OP)
Thanks for all of your help.  An engineer at work finally explained the 2.3 multiplier.  He showed me a graph using a 8.8 X/R ratio that translates to the 2.3 number instead of the 2.82 number.

thanks again

RE: How do you determine Peak current in Sine Wave

Drax,

Like the others said in normal condition the peak of the sinusoidal current is equal the rms current * sqrt (2).
The peak sinusoidal current only depends on the X/R ratio when short circuit happens. During short circuit the first few cycle will have a DC component, which will add to the sinusoidal current. This current is called asymmetrical short circuit current. The peak and the duration of the asymmetry depend on the X/R (Inductive reactance /Resistance) ratio of the AC circuit.

RE: How do you determine Peak current in Sine Wave

(OP)
thanks 1x1x1x for explaining that, even though he showed me a chart, I still didn't understand until your email.  I'm a mechanical engineer trying to learn the electrical side.  
thanks a million,

Drax

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources