I have read that a DC series motor can be operated using AC supply, but there will be excessive heating in the core and yoke and also a low power factor. So, construction is modified to have laminated core and yoke to reduce eddy current losses (heating) and also compensating winding and inter-pole windings to keep the torque same while reducing the turns of the field winding (to improve power factor (but reducing torque)). This is an AC series motor.
My question is, whether this AC series motor will run on DC supply or not?
I am also aware of universal motors, but they seem to be very similar to these AC series motors.
Best Answer
The AC series motor you describe is a universal motor, and will work fine on DC. The speed characteristics will be a little different, since when running on AC there's a significant reactive drop in the field windings that reduces the available driving emf.
Difference between AC series and universal motor -
With the field winding in series with the armature current the motor is insensitive to the direction of current, so once you have the necessary laminations to keep losses down when running on AC the motor becomes universal. Small DC series motors - though there aren't a lot of these, most have permanent magnet fields - are often made with laminated fields, since it's a cost-effective way of achieving the geometry. With bigger DC series motors, the field yoke and pole pieces are often solid steel pieces, forgings, extrusions or PM parts.