what is difference between horizontal and vertical electrical Machine design and construction?

I am thinking of an induction motor. The biggest difference would be in the bearings, I think. The vertical motor must sustain a constant thrust equal to the weight of the rotor. Thrust bearings are not as "good" as horizontal roller bearings. Evidence: most motors run horizontally. One exception is a vertical induction motor used for pumping water from wells. The vertical motor fits better in the well shaft and is coupled directly to the needed vertical pump type.
Regards,
Art Wagner

For large scale energy storage applications i suppose flywheels with extreme heavy Rotors. For that application I would prefer vertical machines. Even hundreds of tons can be levitated with minimal losses when you choose a design like that on the FrontPage of www.homopolar.de

I also think that from the electrical point of view, it might not change, and that the most important difference is the bearing design ; some horizontal designs do not need any axial stop, but vertically you have to check what are the electromagnetic forces (depends on the motor topology). The structural boundary conditions are also different and can lead to a different vibration behavior. Finally for cooling, the natural convection behaves differently, but in most applications the ventilation is forced so there should not be any difference.

From the electrical perspective, there is no difference between horizontal and vertical mounted machines.

From the mechanical perspective:
1) Horizontal machines have bearings designed to hold the motor weight as a radial (vertical plane) loading, with accommodation for axial thrust as necessary. Vertical machines use different bearing systems, because the machine weight is now in the axial (vertical) direction, with tangential ("radial") loading created by the connected equipment and alignment.

2) Lubrication material needs to be considered as well as sealing at bearings and shaft, due to the change in orientation.

3) Some design change may occur in the external support construction for the stator, since the mass loading changes from a 'radial" loading (for horizontal mount) to an "axial" loading (for vertical mount).

4) Enclosure orientation should match the machine orientation: a water droplet will still fall "down", regardless of where "down" is with respect to the machine shaft.

Note that some manufacturers will use the same bearings for smaller frame sizes, regardless of orientation. For example, using the same bearing arrangement for sub-400 frames is fairly typical, since there is hardly any rotor weight and shaft diameters are reasonably small. The bearing arrangements start to change for larger machines, like those with which I work. (In my "world", an auxiliary fan or a lube pump may occasionally fall into a 256 or 315 frame - but far more commonly uses at least a 400 frame!)

It really all boils down to the alignment and driven equipment - because even a low-power, low-torque application can have reasonably high imposed thrust conditions.