i-Socket Autoswitch mod for separate circuits

I'm retiring my loud, underpowered 3 gallon shop vac for a 10A portable dust collector in the works.

The i-Socket Autoswitch powers a tool and a shop vac on the same 120V circuit when the tool draws ~40 Watts of power. If you need more than 15A for both, you can either look into an alternative, or modify the Autoswitch in some way like I have done.

I removed the cover on the i-Socket Autoswitch and used one of its sockets to interface with its into-the-mains plug blades. I use an ATX PSU case to enclose the project.

For switching the other circuit, I use a 30A contactor for HVAC applications. It seems that a "contactor" is a relay without the NC terminals.

I want to delay the vac output so as to not overlap the power being delivered. My dust collector uses double the 10A initially just to get the blower up to speed.

The Small Problem

This small DC relay and switching power supply gets powered by the Autoswitch even in standby, and we don't want that. Same goes for the Delay On Make Timer used alone.


                [ Tool output socket  ]
                [                     ]
      120VAC----[i-Socket Autoswitch  ]
                [                     ]
                [   ~weird relay~     ]
                [                     ]
                [ Vacuum output socket]

In standby, the Autoswitch's vacuum output socket outputs 120V even when the connected tool is not powered. However, it seems to output a low amount of current. In order to get the desired result, use a relay with a 120V coil.

Relay Train


                [table saw, etc]
                  |
                [Outlet sockets]
                  ||
                [ Tool output socket  ]
      CircuitA  [                     ]
      120VAC----[i-Socket Autoswitch  ]
         |      [                     ]
         |      [   ~weird relay~     ]
         |      [                     ]
         |      [ Vacuum output socket]
         |         ||
         |         ||
         |      [ (coil) ]
         |      [ relay  ]
         |        |   |
         +--------+   |
         |          [Delay On Make Timer]
         \________    |
                  |   |
                  |   |
                [ (coil) ]
                [ relay  ]
      CircuitB    |    |
      120VAC _____/   [Outlet socket]------[dust collector]

This configuration works but the delay on make timer takes 5 seconds rather than the advertised 2 minimum. I will redo this at some point using a MCU.

Finishing up

The cord lengths are awkward to use so I swapped a few around to integrate it with the dust collector, now that it works.

I followed this guide with a dusty Teensy2.0 to act as a delay relay. It's much more responsive than the delay on make timer.

The toggle switch allows bypassing the circuitry to directly power the dust collector.

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