Engines operating at temperatures below minus 20 degrees have the following problems:
– Exaggerated condensation – requiring additional drainage or installation of heating resistance if the engine is stationary for long periods;
– Ice formation in the bearings – causing hardening of the greases or lubricants in the bearings, requiring the use of special lubricants or antifreeze grease.
On 0.5 horsepower 56 frame motors operating at ambient temperatures above 40 ° C, winding can reach temperatures that are detrimental to insulation. This has to be compensated by a special design of the electric motor, using special insulation materials or by reducing the rated motor power.
The voltage drop restricts the flux of the magnetic circuit, reducing the losses in the iron and the current in the vacuum, however, the motor torque must exceed the resistant torque to prevent excessive increase of the slip. As the motor torque is product performance between the flow and the intensity of the absorbed current, if the flux smoothes, the current intensity rises. With the on-load current increased by the voltage drop, the motor will heat up, increasing the losses. An increase in supply voltage will have more limited effects, since the no-load current increases as the on-load current decreases.