Autotransformer Motor Controller For Submersible Pump

Google you get complete details

see the link

https://www.google.com/search?q=auto+transformer+starter+for+motors&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiLqJzk2_DNAhVIrD4KHW4LD3gQ7AkIaA&biw=1366&bih=667

What sort of starter do you want, open or closed (Korndorfer) transition.

<..Can anyone let me see a schematic diagram of auto-transformer starter, with auto/manual selector?...>

Yes, indeed. The various manufacturers of this type of equipment certainly can do this as part of their sales process. A search using Google, or any other internet search engine for that matter, will quickly reveal their locations and telephone numbers. Good luck with the search.

I, and maybe others, am curious why you feel you need a reduced voltage starter for your (we assume from the size) 3 phase motor. While the starting torque for a typical centrifugal pump is low, you do have to consider the ability of your power line to deliver current for an extended time while the motor is coming up to speed. If the line is so weak that your lights flicker or go out, an autotransformer may not help.

Your request for Auto-Manual selector wiring and tank level implies that perhaps the reduced voltage starter will allow you to control your cycle time on refilling your tank.

When the motor is running on reduced voltage, you are adding extra heat into the motor rotor circuit, reducing the accelerating torque available, and reducing the voltage drop on your power system supply.

An inverter (variable frequency) with a long ramp time might be a better solution to use with your level switch....