- #1
cliopete
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Homework Statement
The balance equation for a I/P system is:
Pout = (KcY/Ax)*Iin + FsZ/Ax
Where:
Kc = 2500
x+y = 0.1
Z = 0.075
A = 0.05
Kc is the constant of proportionality relating to the input coil and Fs is the force exerted by the zero spring.
a - Determine suitable values of y and x to give a straight line response of 'A' (shown on a graph I havnt put up here)
Homework Equations
Pout = (KcY/Ax)*Iin + FsZ/Ax
Y = Mx + C
The Attempt at a Solution
According to the graph, the intercept (C) of the line runs through zero, thus Its safe to discount the FsZ/Ax part of the equation, leaving me with:
Pout = (KcY/Ax)*In
(Y=mx)
According to the graph, reading values for Pout and In, these are:
@ Pout = 1.0bar then In = 20mA.
putting these values into the formula:
1.0 = (KcY/Ax)*0.02
Transposing gives
1.0/0.02 = KcY/Ax
thus
50 = KcY/Ax
and I know that A = 0.05 and Kc = 2500
50 = 2500*Y / 0.05*Ax
This is where I get a little confused as to the correct method of transposing to give x, I will run through the rest of my working now...
50*0.05 = 2500*Y / x (moving the 0.05 from the bottom of one side to the top - becoming a multiple)
thus
2.5 = 2500*Y/X
2.5/2500 = 0.001
0.001 = Y / X
as mentioned earlier on, x+y = 0.1
so logically, y = 100-x
inserting in the formula...
0.001 = 100 - x / x
shifting the 0.1 across..
0.001 -0.1 = - x / x
Heres the bit where I run into trouble, I am not sure how to deal with the -x / x in order to get it into one value,
Im a little rusty when I get a further into transposition but this is driving me up the wall as its the key moment in the question which unlocks the value for further working.
I tried multiplying each side by x to remove the fraction, ending up with:
-0.099 * (x) = -x * (x)
which I would then assume to give?
-0.099x = -x2 ?
Like I said short of going into see my tutor next week I am a little stuck, if it does square the negative x how do I remove the x on the other side? argh!
Looking back at the working I am not even entirely sure -0.099 is a correct value either but If someone could give guidance on how to deal with the x's that would be great...
thanks in advance...