Recently I came across a Bryant heat pump with a 1.5-pole contactor. They had the crankcase heater wired up across the side of the contactor that breaks the circuit, i.e. one side of the heater connected to L1 and the other side connected to T1. This was consistent with the wiring diagram.

When the contactor is pulled in, there will be no potential difference between L1 and T1, so the heater won't do anything.

Here's where it seems funky to me. When the contactor is not pulled in, the crankcase heater is essentially wired in series with the compressor windings. Apparently the voltage drop through the heater is high enough that the compressor won't spin; instead, the windings will heat up (and help keep the crankcase warm).

Am I understanding this correctly? It seems like that would be hard on the windings. And what happens if the crankcase heater partially shorts to ground?