Progressive starting
These are motors in which a special cast-iron fan/disc is installed, which acts as an energy catalyst, delaying the standard speed at start-up time.
Since the kinetic energy of the fan assembly Ec = (1/2) Jw2 [J], during start-up the motor must work to start the supplementary flywheel; this involves using the starting time with all other conditions being equal.

 

Fly-wheels for motors
Type
Fly-wheel weight (kg)
Fly-wheel inertia (kgm2)

63 / 71

1,0

0,00101

80 / 90 *

2,8

0,00347

100 / 112 *

4,7

0,00991

132 *

7,1

0,0227

160

9,0

0,0639

180 / 200

9,0

0,0639

* Cast-Iron heavy fan

 

Symmetrical windingSymmetrical winding
Two-phase winding distributed symmetrically around the machine circumference, run in single-phase mode with the capacitor always working.
This is used where it is necessary to reverse the motor rotation direction with simple circuits.
It generally offers more noiseless operation than a traditional single-phase winding, though at the cost of reducing the starting torque (-20%).

Defluxed winding
Winding in which design criteria have been adopted so that the powers obtained are below standard, all other conditions being equal, thereby limiting the peak temperatures.
Used in heavy-duty applications, such as with low rotation speeds, where self-cooling of the motor is scarce.