lecture_16

# lecture_16 - MIT OpenCourseWare http/ocw.mit.edu 2.004...

This preview shows pages 1–4. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MIT OpenCourseWare http://ocw.mit.edu 2.004 Dynamics and Control II Spring 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms . L L 8 = > I i n d i c a t e s t h a t w e a s s u m e L > L > = = > . I i n d i c a t e s t h a t w e a s s u m e t h e c u r r e n t f l o w i n t h e d i r e c t i o n o f t h e a r r o w o r t h a t t h e s o u r c e a c t s t o m o v e n o d e = i n t h e p o s i t i v e r e f e r e n c e d i r e c t i o n i n a m e c h a n i c a l s y s t e m Massachusetts Institute of Technology Department of Mechanical Engineering 2.004 Dynamics and Control II Spring Term 2008 Lecture 16 1 Reading: • Class Handout- Modeling Part 3: Two-Port Energy Transducing Elements 1 Arrow Conventions on Ideal Sources To this point we have simply told you to draw the arrows on source elements (a) In the direction of the assumed across-variable drop for across-variable sources (voltage and velocities), (b) in the direction of the assumed through-variable direction for through-variable sources (currents and forces) When we draw a branch on a graph we make the assumption that P > 0, that is that power is ﬂowing into the element. There are in fact two arrows implicit on each branch: one representing the assumed across-variable drop, and a second representing the assumed through-variable direction. If P > (power is ﬂowing into the element), the two arrows are in the same direction. For example, consider a capacitor 1 copyright c D.Rowell 2008 16–1 S y s t e m 1 I a c r o s s - v a r i a b l e d r o p t h r o u g h - v a r i a b l e d i r e c t i o n 4 d r o p +- E 4 d r o p E Z Z Z v = s V 1 2 F s 1 2 3 L o o p 1 : v + v - V = 0 Z 1 s Z 2 L o o p 2 : v - v = 0 Z 3 Z 2 + L > L = E + d r o p L + = > E + L + = > v o l t a g e d r o p a n d c u r r e n t i n t h e s a m e d i r e c t i o n v o l t a g e d r o p a n d c u r r e n t i n t h e o p p o s i t e d i r e c t i o n P = v c i c > when either P = v c i c < when either 1. v c > and i c > 0,or 1. v c > and i c < 0,or On 2. v c < and i c < 0. 2. v c < and i c > 0....
View Full Document

{[ snackBarMessage ]}

### Page1 / 12

lecture_16 - MIT OpenCourseWare http/ocw.mit.edu 2.004...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online