Is there a rotational standard for AC single phase motors? A default rotation? If I purchase 100 single phase AC motors worldwide.......will they rotate in the same direction?

What about DC motors?

How about gas and diesel engines? Anybody know? Is there an engineering default rotation?

 

Is there a rotational standard for AC single phase motors? A default rotation? If I purchase 100 single phase AC motors worldwide.......will they rotate in the same direction?
What about DC motors?

Not that I have ever come across, purely arbitrary. Polarity and phase dependent.
Unless north of the equator!

How about gas and diesel engines? Anybody know? Is there an engineering default rotation?

From experience, usually CW viewed from the front of the input/drive shaft. As per the old Hand crank start versions.

Max.

 

Ref IEC 34-8 "Marking of terminals and direction of rotation of rotating machines."

see page 48 of this document.

 

This is in reference to single phase and DC motors. Ok Max....let me ask you this. When someone buys a single phase or a DC motor.....is the rotation direction selectable? Like the frame type or shaft size is selectable? Is it common to be able to buy the same two motors with opposite rotations?

In other words....a replacement motor(different manufacturer) with the same frame, electrical ratings, and shaft size.....the rotational direction can not be assumed to be correct with the same wiring code, right?

Is the rotational manufacturer's spec........ just as important as any other spec.

I understand that the wrong rotation can be nullified/corrected in a number of ways.....whether it be on the input or output. Maybe that's why it's a mixed bag.

 

Single phase AC motors fall into a few categories, the simple small shaded pole (fan) motor is made for one rotation direction only, the only way to reverse is to flip the rotor 180°.
For the rest, which is mostly capacitive start/run, either the run or start winding has to be reversed with respect to the other.
There is also the PSC , permanent start cap motor up to around 1/2 hp where both winding's are equal and the reversal is done by simply swapping the function of start and run winding over by a simple SPDT sw to apply the start cap to either one in turn.
PM DC motors are reversed by simply reversal of supply polarity, the exception would be the wound field motor, as opposed to the PM field, where it is necessary reverse the field WRT the armature.
If you buy a motor replacement that is not identical, it is a moot point whether it will run in the same direction.
At one time when you purchased a motor the common direction notation was referenced looking into the shaft end, but some I have recently purchased the direction was with reference to looking from the opposite end, which has resulted in some confusion. Not sure why the change?
Max.