The standard relay in most Gizmo Engineering products is rated for a 15A load.  For applications where this is not enough, this 40A relay can controlling high power devices. 

 This will often necessitate a larger enclosure which is included in the price.  Also Includes a terminal barrier strip, fuse, 10 ft of 8 gauge wire, and larger cord grip.  Part number is denoted as suffix –R40

When deciding on the maximum current load needed, you will need to know the “locked rotor” amps.  If you’re luck it will be on the motor nameplate. Otherwise you can measure it with a clamp-on ampmeter.  Or use the calculator on this page.

Datasheet for American Zettler AZ2280-1A-12DF