A common 11880 steel can Ford type "solenoid" with silver contacts and a 36 ohm coil will instantly fail if a 200+ ampere load is applied across the load contacts.
A five dollar phenolic case Ford starter solenoid is rated for 800 amperes make or break for thousands of cycles. But with a 2.0+ ohm coil is will overheat after a few minutes and fail.
The tower-type Trombetta solenoid is generically referred to as an "Essex Type" solenoid. They are a definite design improvement over the Ford style solenoid.
To avoid make and break flashover deterioration of the contacts, serious solenoids are mercury filled.
Some posters are missing the point. A solenoid has a definite design limit on capacity. Make and break flashover is the major cause of solenoid contact failure.
NUMBER OF CYCLES, make and break at load is a crucial value.
Gear reduction (planetary gears) is becoming more common and it is needed. When did Chevrolet and Ford 454 and V10 engines switch to planetary gear reduction starter motors?
