Mains soft start

My shop is powered by a 50m extension cable driven from a wall socket in the house. When the table saw is started it draws so much current that their is a significant voltage drop over the cable. This drop means the shop lights go out, sometimes for up to 5 second.

To solve this I want to build a soft start circuit that limits the huge inrush current from the table saw.

This is the circuit I plan to use:

All the ports collected together.

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This project had been stalled, since I really didn't like that the table saw controls could not be used to start/stop the load. The above circuit required a switch before the soft-start and table saw.

After mulling it over for some time, and a few iterations a new circuit was created.

The first bridge rectifier is shorted out to pass current directly through the main current limiting resistors and into the load. However, the rectifier produces a stable voltage drop. By tapping off the this voltage drop, a dc voltage of around 2 volts can be created - that's only present when the load is pulling current. This load sensing voltage is used to switch, through a simple time delay RC circuit, an opto-couple, that in turn switches a triac that controls the full AC voltage into the relay coil.

Finally, the relay shorts out the main current limiting resistors allowing full current to flow to the load.

Happily, the second relay switch can be used to control other devices, such as a shop vac.