Controlling AC motor with relay vs. switch on motor
Protection circuitry would not actually &quot;contain&quot; a switch that could start and stop a motor. A switch could be packaged as a manual motor starter that contains motor protection components or circuitry and possibly the means of controlling a starting capacitor.
If a switch that is controlled by protection circuitry is wired in series with a relay is not removed, but just left in place and connected in series with a relay it would still protect the motor. If the protection circuit causes it to open, the relay will be unable to start the motor until the switch is re-closed. The method of controlling the starting capacitor would need to be evaluated, but is likely that would respond to motor current and perform normally.
If the manual motor starter is removed or bypassed, then everything that it contains would also be removed or bypassed.
A manual motor starter is a product that has features and functions that should be described in detail in literature provided by the manufacturer. There is no way to completely determine how it functions without examining the literature for the specific product. This answer provides only a general idea of what to expect.