There is a huge impact on the electrical motor heating with its performance. So it’s always better to have eliminated the heat in an electrical motor to obtain its best performance. most of the energy losses are get from as the temperature in electrical machines. Today we are the plan to discuss some important feature of the heat and temperature in electrical motor and its effects on an entire system.
Hot Spot Temperature in Electrical Motor
Hot Spot means that the most heated point in a machine. This often occurs on the conductor at the middle of the slot. So hot spot temperature will be the highest temperature apply to the insulator. For safe working of insulation, the hot spot temperature should be kept at vale adequately below the upper-temperature limit for the particular part of the insulation.
Temperature Gradient of Electrical Motor
Even at this steady state thermal conditions, there is a temperature distribution among the different parts inside of the electrical machines. The temperature gradient measures the difference in the steady state temperature between two given points.
For example, the end winding temperature can be large differences from the hot spot temperature. By making an assumption as the heat cannot escape radially due to the thick insulation cover.
The temperature gradient measures the difference in the steady state temperature between two given points.
For example, the end winding temperature can be large differences from the hot spot temperature. By making an assumption as the heat cannot escape radially due to the thick insulation cover.
Temperature Rise
The overall increase of winding temperature is above the ambient temperature is known and temperature rise of the electrical machine.
The overall increase of the temperature is estimated on the basis of increased winding resistance.
Let
R1 – winding resistance when the motor is at ambient temperature
R 2– winding resistance during the operation of the motor
α – Temperature coefficient of resistance for the copper
Then
R2 =R1 (1 +αθ)
Θ = R2 -R1R1α
Motor manufacturers specify the safe upper limit of the temperature rise that automatically ensures the “Th” is below its critical limits.
Manufacturer of electrical machines also provides two temperature values such as.
1). Full load temperature rise – The steady state temperature under full load conditions is known as full load temperature rise.
2). Maximum temperature rises – The maximum permissible temperature is the maximum temperature rise of the electrical machine.
Types of Losses in Electrical Machines
Types of Losses in electrical machines can get categorize into two main sections such as
Fixed losses – Fixed losses includes core loss, rotational losses.etc.
Variable losses – Variable losses represents copper losses which are dependent on load.
When
P – Fixed Losses
Q – Variable losses at full load
X – per unit load (output)
The total losses when machine operated at load per unit = P + x2 Q
In here we have discussed on some basic information regarding the effect of temperature in electrical motor and we are the plan to discuss more information and features of it in near future.
