The electrical motor's cooling system
During operation, the electrical machines transform the absorbed energy from the grid into a mechanical one. However, not all of the absorbed energy is transformed into useful one: the passage of the electricity in the coils, the magnetization of the magnetic circuit, the rotation of the machine and other minor phenomena contribute to the production of thermal energy resulting in loss of energy for the whole system.
Consequently, an adequate cooling system to keep the machine and the related insulating products within certain temperature limits is needed.
The easiest and common way to cool the machine is removing the heat by introducing air around the machine itself. For most electrical motors, their carcasses are equipped with air inlets and fans mounted directly on the motor shaft in order to increase the airflow.
In poultry and industrial environments, there are many impurities. Pollen, in particular, is a highly aggressive substance that has insulating properties and therefore it makes the heat dissipation of the engines very hard.
Termotecnica Pericoli chooses to use, where possible, electrical motors without any cooling fan. This is only possible by positioning the motor in a particular area of the fan, where the cooling is guaranteed by the air flow produced by the fan itself.
This choice has been made by our technicians in order to protract the cleaning intervals: the use of electric motors with cooling fan – especially in aggressive environments like poultry sheds- involves a greater accumulation of dirt (especially close to the fan) and therefore a frequent maintenance.
Problems caused by the overheating of the components to the electrical motor
We have three main aspects to consider:
- In case of severe overheating, the insulating resins around the coils may liquefy, thus leading to short circuit of the motor.
- In case of overheating of lower intensity, the grease inside the motor bearings may suffer: the high temperature can cause liquefaction and leakage of the grease. If the bearings function without grease, the motor will stop working after a while.
- A temperature higher than the estimated one leads to a higher electrical resistance of the coils, and, consequently, a lower efficiency and RPM of the motor. Therefore, we will have for example an exhaust fan absorbing more energy from the grid and at the same time producing less airflow than the expected one.
In conclusion, a clean electrical motor prevents failures and increase motor lifespan and, most important, the motor can reach the desired performance by consuming less energy, thus resulting in lower overall running costs.