Axial, Radial and Transverse (or Transversal)

My understanding (open to correction) :

Axial - along the axis (for a motor, in the same axis as the shaft)

Radial - at right angles to the axial plain (in the direction of the "radius).

Transverse - Adjective - at right angles to an axis (crossways) - usually the long axis(Mathematics and astronomy use the term slightly differently)

Transverse - Noun - some thing that is at right angles.

Transversal - Noun - some thing that intersects more than one line or axis.

Kaizan's correct, but 'tranverse' needs more explanation.

Imagine a flat plane, say a piece of paper. Imagine that the length of the motor's circular shaft goes into and comes out the paper. The intersection of the shaft and the paper is circular ... it's the cross-section of the shaft.

The shaft's axis (assuming a circular shaft) is a line that 'goes into' and 'comes out of' the paper and that intersects the paper at the centre of the circular cross-section. The position of a point in relation to that line (the axis) is the point's axial coordinate, that is 'how far it is down the axis'. To determine the position, you draw a line from the point to the axis so as to form a right angle between the line and the axis.

Now, imagine that the piece of paper has the same axial position as your point. The line that you've just drawn to form a right angle (90 degrees) to the axis will appear as a line drawn from the point to the centre of the circular cross-section drawn on the paper. (Since the axis goes straight into the papet and out of it, perpendicularly to the paper, a line drawn to the centre of the circle on the paper will necessarily be perpendicular to the axis). The length of the line drawn from the point to the axis is the radius at which the point is located in relation to the axis. That length is the radial coordinate.

And now, the last coordinate. A point with known axial coordinate will be located on a plane perpendicular to the axis; we represent that plane by our piece of paper. If, in addition to that, we know the radial coordinate, then we know how far from the axis the point is. That being said, the point's location can be anywhere of a circle whose radius from the axis is equal to the radial coordinate. Now, we have to say where on the circle of known radius the point is located.

We do that by measuring the angle between the line drawn from the point to the centre of the circle (i.e., to the axis) and a line drawn from the centre in any direction on the piece of paper. That line we define as being the reference line for measuring angles ... by definition, its direction is zero degrees.

So, the angle formed between the radial line drawn from the point to the circle's centre (the axis) and the reference line (zero degrees) is the 'tranverse' or 'angular' coordinate that locates the point precisely in space.

Summarily:

- the axial coordinate defines where our piece of paper intersects the motor shaft, perpendicularly; our point is located somewhere on that piece of paper;

- the radial coordinate tells us how far the point is from the centre (the axis) of the shaft whose cross-section is circular; with the axial and radial coordinates, together, tell us that the point is on our piece of paper (axial coordinate) and that it's on a circle of a given radius (the radial coordinate) and whose centre is the shaft's axis;

- the tranverse (i.e., perpendicular to the radius) or 'angular' coordinate tells us where the point is one the circle defined by the axial and radial coordinates.

And of course, now is when I realize that I could have just pointed you to Wikipedia. The coordinate system that I've described is the polar coordinate system. Here it is on Wikipedia: http://en.wikipedia.org/wiki/Polar_coordinates

DZ :-S