Some 240 v motors (called universal motors) have a DC commutator winding and a rectifier to covert to DC. You would find these in washing machines and very old power drills which run on 24 v DC or 240 AC
Sorry, your concept of a universal machine is wrong.
They have a commutator (never heard of a DC commutator)
They do not employ any form of rectification.
This type of motor is basically a series wound machine with virtually the same electrical characteristics. They give a high torque output at low speed (ideal for starting a load from rest) and high speed at low loads. They are invariably fitted with a cooling fan which acts as an air brake so that if the drive belt breaks the motor (being thrown into a no-load situation) will accelerate but will not reach critical destruction speed. They are commonly used in small appliances such as vacuum cleaners and spin driers. If the fan is removed, the no-load speed will increase until there is a very high risk of the armature widings "birdcaging" i.e. they are thrown outwards by centrifugal force. The windings are normally held in their slots by insulated packing to prevent this. The weak spot is often the gap between the commutator risers (the connection point for the armature windings and the commutator segments) and the armature. There is often a binder applied and varnished into place over this area.
There is only a small clearence between the armature and the pole pieces. If the two come together (at around 20k RPM) the results are "interesting".
In general, it is bad practice to belt drive with any series machine above fractional horsepower rating. Always employ a solid drive.
Regards.