An auger is a rotating metal shaft with a blade at the end that feeds a small number of pellets from the grill hopper to the firepot. The igniter rod/Hot rod lights the pellets and primes the fire, raising the grill to an initial starting temperature based on the controller setting.
The term “auger motor” refers to a device, consisting of an electric motor and a reduction gearbox, that turns an auger shaft at a predetermined rate (typically 2 RPM's, but this can vary) to deliver fuel (i.e., wood pellets) from the hopper to the firepot in a pellet grill.