How Do You Calculate Temperature Rise in Copper Windings?

The formula being used is Tii = (1+a*ti)/(Ri/Rii), where Tii is the temperature rise of the copper windings, ti is the initial temperature of the windings (22 degrees), Ri is the initial resistance (5.8ohms), and Rii is the final resistance (6.8ohms). This formula takes into account the temperature coefficient (a) to calculate the temperature rise of the windings after running for several hours. The calculation you have done is correct, which gives a temperature rise of 1.28 degrees. However, it is possible that there is an error in the given data or in the calculation itself, so it is important to double check your work.
  • #1
Red_shift
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0

Homework Statement


The copper windings of a motor have a resistance of 5.8ohms at 22degrees when a motor is idle.After runnning for several hours the resistance rises to 6.8ohms. what is the temperture rise of the windings? assume a constant temperture coefficient of a = 5*10^-3

Have i got the right formula for this problem? or have I missed a step? I quite sure my working is correct but the answer definitely is'nt. Please help

Homework Equations



Tii = (1+a*ti)/(Ri/Rii)

The Attempt at a Solution



Tii = 1+5*10^-3*22/(5.8/6.8)

Tii = 1.088/(5.8/6.8)
Tii = 1.28 degrees (2 d.p.)
 
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  • #2


Red_shift said:
Have i got the right formula for this problem? or have I missed a step? I quite sure my working is correct but the answer definitely is'nt. Please help

Homework Equations



Tii = (1+a*ti)/(Ri/Rii)

Explain this formula, as it does not look right. What are Tii, ti, Ri, Rii?


ehild
 

1. What is the definition of temperature coefficient in electrical engineering?

The temperature coefficient in electrical engineering refers to the change in electrical resistance or voltage of a material or component as a function of temperature. It is typically measured in parts per million (ppm) per degree Celsius (°C).

2. How does temperature coefficient affect electronic devices?

The temperature coefficient can have a significant impact on the performance and reliability of electronic devices. As temperature increases, the resistance of materials used in electronic components can also increase, causing changes in voltage and potentially leading to malfunctions or failures.

3. What are the different types of temperature coefficients?

There are two main types of temperature coefficients: positive and negative. A positive temperature coefficient means that the resistance or voltage increases as temperature increases, while a negative temperature coefficient means that the resistance or voltage decreases as temperature increases.

4. How is temperature coefficient calculated?

The temperature coefficient is calculated by measuring the change in resistance or voltage of a material or component over a specific temperature range. The change is then divided by the original resistance or voltage and the temperature range in degrees Celsius to determine the coefficient in ppm/°C.

5. Can temperature coefficient be controlled or compensated for?

Yes, temperature coefficient can be controlled or compensated for in electronic devices through the use of materials with specific temperature characteristics, such as thermistors or compensating resistors. Additionally, circuit design techniques can be employed to minimize the effects of temperature on the performance of electronic components.

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