Finding resistance and temp co-efficient

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SUMMARY

The discussion focuses on calculating the temperature rise of a motor winding with a resistance of 80 ohms at 20°C, which increases to 100 ohms after 4 hours of operation. The temperature coefficient of resistance is given as 1/234.5°C. Using the formula for resistance change, the calculated temperature rise is 63.63°C, resulting in a final temperature of 83.63°C. The solution is confirmed as correct, despite initial temperature considerations.

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Homework Statement


A motor winding has a risitance of 80 ohm at room temperature of 20c before
switching on to a 230v. after 4 hour run wionfing resistance is 100 ohm
find the temperature rise if the matrial resistance temperature co-efficient is 1/234.5/c.

R at 20 = 80 ohm
R at t = 100 ohm
alpha =1/234.5

Homework Equations


R at 20/R at t = R at 0c (1 - at)/ R at 0c (1-at)


The Attempt at a Solution



80/100 = 1+0.004264X20/1+0.004264t

t = 83.630 c

Rise is t-20 = 83.630-20
t rise is 63.63 c
 
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The rise does not take into acount the initial temperature as if it were in Kelvin it would have been 293.5. The actual result should be 83.63.
 
Lok said:
The rise does not take into acount the initial temperature as if it were in Kelvin it would have been 293.5. The actual result should be 83.63.


but solution is right? and answer 83.63 is ok with this statement
 

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