Resolver/Encoder

Had a unique question today and can not get a bare bones answer.

We have a resolver (several of the units) and when they go out, you start getting missed pulses/inaccurate readings. So the machanic I am working with ask why this happens. Bad bearings, sticky unit, throw a new one on and run.
No good enough, he really wants to know how it works.
Okay, it sends x amount of pulses out, depending on its windings (not optical), per revolution. The Programmable Limit Switch counts these and gives us our angular position.
Still not good enough for him and now I am curious to know the more detailed workings of how this thing truley gives us x-pulses per revolution.

Is it number of poles or what that sends out the ppr?

Looked around google and searches here, lots of applications, but no details.

resolver is a type of transformer used to measure angular position:
it has three coils, one of them is driven by AC, and the other two
are used as signal pick up. depending on angle of the moving coil
signal in secondaries will change (get stronger or weaker or change polarity
if driving coil is turned 180deg).
pickup coils A and B are displaced at some fixed angle (such as 90deg)
so their signals will be different. let's say moving coil is at some 10deg.
pickup coil at 0deg (A) will have very strong signal but B (the second pickup
coil which is at 90deg) will have very weak signal. as the moving
coil is turned by something (motor or whatever) to 45deg. both
pickup coils will have same signal. if the rotation continues to 80deg or so,
pickup A will produce strong signal and B will get weaker (just a SIN and
COS functions...).
the same happens with the LVDT the only difference is that LVDT movement is linear...
the accuracy of the feedback depends on couple of things but limiting factor
is usually electronics doing conversion (ADC used for sampling).

check following link
http://www.amci.com/tutorials/tutorials-what-is-resolver.asp