Starter solenoid failure question

[MilesA]

Question: Is it possible / known that a starter solenoid can fail such that it continues to supply power from the battery to the starter motor after the car fires up and the ignition key or starter button is released?

Helping a friend with another classic who's car came to a halt after a short distance with an extremely hot and burnt out start motor. Set up similar to my 3A: ignition and starter switch, separate starter solenoid wired to battery, starter motor, ignition switch and regulator. Ignition switch would be the principal culprit but then I wondered about the solenoid sticking 'open'.

Thanks

Miles

[RobH]

Yes Miles, it is possible. If the contacts stick shut when the engine starts, the motor will probably stay in mesh with the ring gear which is not good for the motor mechanically or electrically.  

That could be due to a fault on the ignition switch, if the solenoid operating coil remained energised.  Other possibilities are that the solenoid contacts can weld together which is less likely, or the solenoid moving armature could get stuck in the operated position preventing the contacts from opening again, perhaps if the return spring breaks. 

[MilesA]

Thanks for the confirmation Rob. 
 

As you know I am no expert but it seemed to me as a matter of common sense that this was possible. My friend can now have an informed discussion with his garage.

Miles