A low reading on an ohm meter means a good (low resistance) path. A high reading means a very poor path or open.
The slip rings on the rotor should have a very low reading between them, but individually to the shaft should be open.
TO maybe help get an idea of how this all works, a simple test. When you touch the meter leads together (meter on ohms) the meter (digital) will read .05 or somewhere close. Apart, the meter reads 0. or has a dash. Lots of different ones out there and rarely manufacturer's use the same indication.
OK not hold one lead in each hand between your thumb and forefinger- What's the meter reading? Remember that number. It'll probably be jumping around a bit so maybe get a rough average- right here this is not a real accurate test- Just a simple rough idea to give you a idea of how the meter reads- Got your average number? Good, now wet the fingers you were holding the meter leads with and grab them again just like you had them. DOn't worry, not enough voltage or current here to even feel it. Now look at the numbers on the meter again- they will be lower- the water on your fingers makes you a slightly better conductor.
Not a real scientific test, but it may help shed a little light on how a meter reads.
If you already know- sorry, I am not trying to make anyone look bad- but someone else may be trying to work thru a meter and this might help them too. And the way things are worded sometimes make a ohm meter as confusing as it can be and when you tie that with some guys are (rightfully) afraid of anything dealing with electricity ------