The phrase "a system that usually" is correct and usable in written English.
You can use it when describing a system that typically operates in a certain way or has a common characteristic.
Example: "The software is designed to be a system that usually adapts to user preferences over time."
Alternatives: "a system that typically" or "a system that commonly".
It is not a system that usually rewards extremism.The differences are largely of personality.
After that only ACARS, a system that usually relays engine and other flight data, left a clue to the plane's whereabouts: a series of "pings" picked up by the system's satellite that put it in one of two "corridors" (see map).
Royal Mail estimated they would have carried out an extra 25,000 rounds by Christmas, in a system that usually sees 68,000 daily rounds covering more than 28m addresses.
No doubt they feel too busy, too harassed, too tuned out of a system that usually ignores their existence.
Distribution feeders have a simple protection system that usually employs overcurrent relays.
In the tropical latitudes, tropical storms and hurricanes generally move westward with a slight tend toward the north, under the influence of the subtropical ridge, a high pressure system that usually extends east-west across the subtropics.
The panel ruled in November 1970 that the orchestra was not guilty of racial discrimination but said it had "engaged in a pattern and practice of discrimination" regarding the hiring of substitute and extra musicians: an old-boy system that usually relied on the students of players.
If you don't want to sleep, you've got Bose headphones to use with an extensive audio-video system that usually includes at least a few dozen movies to choose from.
Autosomal dominant disorders include Huntington's chorea, a degenerative disease of the nervous system that usually does not develop until the carrier is between 30 and 40 years of age.
"You have this system that usually produces a branching tree structure and when it breaks produces these incredible brain-shaped flowers full of convolutions and folds.
Looking back I see how my anxiety worked kind of like the way an autoimmune disease works—when the immune system that usually protects you starts attacking your body.
