Sounds like the same principle as a load shedding relay - e.g. www.kempstoncontrols.co.uk/.../1810847 (just a random google found example) - although the output might be reversed in terms of on/off for load/noload.
(I've used one similar to that to knock together a box that switches the workshop vacuum on when a power tool starts up).
Sounds like the same principle as a load shedding relay - e.g. www.kempstoncontrols.co.uk/.../1810847 (just a random google found example) - although the output might be reversed in terms of on/off for load/noload.
(I've used one similar to that to knock together a box that switches the workshop vacuum on when a power tool starts up).
