Question

A shunt winding of a motor has a resistance of 85 ohms at a room temperature 22° when the motor runs on full load, It's resistance increases to 100 ohms. Find the rise of temperature of the winding. If the resistance temperature coefficient of winding per D.C 0°C is 0.004?​

Answer 1

Answer:

66.12 degree Celsius

Explanation:

We are given that shunt winding on motor has a resistance =85 ohms

Temperature==$T_ref=22 degree Celsius</p><p>Resistance =R=100 ohm</p><p>Coefficient of resistance temperature =[tex]\alpha=0.004$

We have to find the value of temperature rise of the winding

Using formula

$R=R_ref(1+\alpha(T-T_ref))$

Substitute the value then we get

$100=85(1+0.004(T-22))$

$\frac{100}{85}-1=0.004(T-22)$

$T-22=\frac{15}{85\times 0.004}$

$T-22=44.12$

T=44.12+22=66.12 degree Celsius

Hence, the rise of temperature of the winding =66.12 degree Celsius.

Answer 2

Answer:

70° C

Explanation:

When initial temperature is not 0° C , formula used for temperature coefficient is

α = (R2 - R1) / (R1*T2 - R2* T1 )

by putting values

0.004= (100-85) / (85*T2 - 100* 22)

85*T2-2200= 15/0.004

85*T2=3750+2200

T2=5950/85

T2=70° C.