Depending on the machine... choose where you plug it in carefully!
As an example if you have an Airflex Turbo, Jag etc...
It will have 2 power cables... run each cable to a separate 13 amp wall socket, if required then use good quality extension leads which are rated at 3100 watts each... Always make sure they are fully un wound and without fail always use RCD breakers.
Never switch both motors on at the same time, vac 1... wait 3 seconds then vac 2.