For a given load:
Increase in supply voltage results in increase in armature drop. Increase in armature drop results in higher armature current. But we know that speed is inversely proportional to armature current.
We also know that increase in supply voltage increases speed. What am I missing here?
Edited to make the question clear as to what I'm asking
Best Answer
Let's imagine the following:
No. Speed is proportional to voltage. If you try to stall a motor running on constant voltage you will see the current rise. However, given a constant voltage the current will decrease as you approach the speed for that voltage. That may be the source of your confusion.
You could get a good feel for this if you have access to a lab power-supply with a voltage and current meter along with a suitable DC motor. Try running the motor in constant voltage mode an in constant current mode.
From the comments:
This is kind-of a redundant statement. For a permanent magnet motor the supply voltage is the armature voltage.
simulate this circuit – Schematic created using CircuitLab
Try thinking of it like this: