Definition of "variator" [variator]

• In experimental psychology, the device which secures uniform change of pitch in Stern's tone-variator; in the old pattern of the instrument, the mercury trough; in the new pattern, a metal cam. See tone-variator. (noun)
• A device for producing desired variations, usually in power or in speed; specifically, in the practice of motor-drawn trains of vehicles on the highway, each unit of which has its own propelling motor, a device attached to the leading and guiding vehicle, by which the limits of speed in each change-gear of the following vehicles may be reduced between determined limits without a resetting of the change-gear lever on each. (noun)
• A joint used in underground electrical mains to allow for the expansion or contraction of the metal with changes of temperature. (noun)

The Century Dictionary (Public Domain)

• "In these conditions, the variator-flywheel system can assist the launch of a vehicle which has slowed down or come to a standstill, by utilising the kinetic energy stored in the flywheel."
• "“The variator weighs less than 5kg in these applications and provides a high level of mechanical efficiency, enabling the overall mass of the mechanical KERS systems to be minimised,” says Chris Greenwood, technology director at Torotrak."
• "The variator-flywheel solution is being developed by a partnership of two companies, Torotrak and Xtrac:"