The maximum temperature that the thermal insulation components of the electric motor can withstand is computed to ensure a skilled operation in an environment with a temperature of approximately 40 ° C. A voltage drop can limit the flow of the magnetic circuit, resulting in reduced iron losses and the no-load current.
However, the motor torque must exceed the resistant torque, preventing excessive slippage. As the motor torque is a function of the product between the flow and the intensity of the absorbed current, if the flux decreases, the current intensity increases automatically.
With the current under high load due to the voltage drop, the motor must warm up and may increase the losses. An increase in supply voltage will have more limited effects, as the vacuum current expands, while the under load current smoothes.
It is therefore important to check and control the ambient temperature so that it does not pass the determined values for which the engine has been schematized. It is important to exercise caution regarding voltage variations. The thermal equilibrium of an engine is changed at the instant the supply voltage changes.