82 Celica choke voltage

Does anyone know why the voltage at the choke bi-metallic coil is 17.2v? The voltage is nominal everywhere else. I have installed a Weber carb, and now I'm chasing down some electrical problems related to an intermittent won't crank problem. Any insight would be appreciated.
I found the answer to my own question. After some repair to the wiring harness, voltage at the choke decreased to 15.7v. The wire to the choke goes indirectly a special connection on the alternator, and seems to be the same as the alternator field voltage. Toyota designed it this way.