Disclosed is a dual motor unit for a flywheel mass accumulator, with at least two electric machines coupled to a common rotary body; wherein the electric machines have different power characteristics and the dual motor unit is adapted to provide a total operating power in an operating speed range (Ω) by an interaction of the electric machines. The power characteristic (P.sub.max) is non-linearly dependent on a rotational speed (ω) of the common rotary body.

Disclosed is a dual motor unit for a flywheel mass accumulator, with at least two electric machines coupled to a common rotary body; wherein the electric machines have different power characteristics and the dual motor unit is adapted to provide a total operating power in an operating speed range (Ω) by an interaction of the electric machines. The power characteristic (P.sub.max) is non-linearly dependent on a rotational speed (ω) of the common rotary body.

An exemplary distributed propulsion system with thermal management includes two or more rotors individually controlled by associated motors and an input control connected to the associated motors to demand the associated motors produce a demanded thrust, wherein a motor power output of each motor of the associated motors is independently controlled to produce the demanded thrust and to control a motor temperature of one or more of the associated motors.

An exemplary distributed propulsion system with thermal management includes two or more rotors individually controlled by associated motors and an input control connected to the associated motors to demand the associated motors produce a demanded thrust, wherein a motor power output of each motor of the associated motors is independently controlled to produce the demanded thrust and to control a motor temperature of one or more of the associated motors.

An eccentric mass vibrating system comprising: a first motor having a first shaft; a first eccentric mass connected to said first shaft; a second motor having a second shaft; a second eccentric mass connected to said second shaft; said first motor and said second motor are adapted to be associated with an object to be vibrated; said first motor and said second motor being electrically adjustable so as to arrange said first eccentric mass and said second eccentric mass at a predefined angle therebetween; said first motor and said second motor being adapted to be positioned on an object to be vibrated; characterised in that it comprises: at least one sensor associated with said object to be vibrated, and a control computer of said system adapted to modify said predefined angle if the value measured by said sensor exceeds a predefined value.

An eccentric mass vibrating system comprising: a first motor having a first shaft; a first eccentric mass connected to said first shaft; a second motor having a second shaft; a second eccentric mass connected to said second shaft; said first motor and said second motor are adapted to be associated with an object to be vibrated; said first motor and said second motor being electrically adjustable so as to arrange said first eccentric mass and said second eccentric mass at a predefined angle therebetween; said first motor and said second motor being adapted to be positioned on an object to be vibrated; characterised in that it comprises: at least one sensor associated with said object to be vibrated, and a control computer of said system adapted to modify said predefined angle if the value measured by said sensor exceeds a predefined value.

Described herein are appliances such as a vacuum cleaners having an air flow passage and a fan assembly provided in the air flow passage. The fan assembly includes (a) a first motor comprising a first rotor, a first stator, and a first rotatable output shaft drivingly connected to the first rotor; and (b) a second motor comprising a second rotor, a second stator, and a second rotatable output shaft drivingly connected to the second rotor. The first rotatable output shaft is driving connected to the second stator; and a fan blade drivingly connected to the second rotatable output shaft. Also described herein are methods of energizing a fan assembly of a portable appliance.

Described herein are appliances such as a vacuum cleaners having an air flow passage and a fan assembly provided in the air flow passage. The fan assembly includes (a) a first motor comprising a first rotor, a first stator, and a first rotatable output shaft drivingly connected to the first rotor; and (b) a second motor comprising a second rotor, a second stator, and a second rotatable output shaft drivingly connected to the second rotor. The first rotatable output shaft is driving connected to the second stator; and a fan blade drivingly connected to the second rotatable output shaft. Also described herein are methods of energizing a fan assembly of a portable appliance.

Described herein are appliances such as a vacuum cleaners having an air flow passage and a fan assembly provided in the air flow passage. The fan assembly includes (a) a first motor comprising a first rotor, a first stator, and a first rotatable output shaft drivingly connected to the first rotor; and (b) a second motor comprising a second rotor, a second stator, and a second rotatable output shaft drivingly connected to the second rotor. The first rotatable output shaft is driving connected to the second stator; and a fan blade drivingly connected to the second rotatable output shaft. Also described herein are methods of energizing a fan assembly of a portable appliance.

A dual motor actuator according to an embodiment includes a main motor actuator outputting torque to a main output shaft by including a main motor and a main reduction gear, an auxiliary motor actuator outputting torque to an auxiliary output shaft by including an auxiliary motor and an auxiliary reduction gear, and a clutch connecting the main output shaft and the auxiliary output shaft to each other, wherein the clutch includes a fixed clutch connected to the main output shaft and a movable clutch coupled to or released from the fixed clutch and connected to the auxiliary output shaft, and the dual motor actuator further includes an output unit connected to the movable clutch and transmitting an output from the main motor actuator or the auxiliary motor actuator.