Search results
Results from the WOW.Com Content Network
A small reaction wheel viewed in profile A momentum/reaction wheel comprising part of a high-accuracy Conical Earth Sensor to maintain a satellite's precise attitude. A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through conservation of angular momentum. [1]
CMGs differ from reaction wheels. The latter apply torque simply by changing rotor spin speed, but the former tilt the rotor's spin axis without necessarily changing its spin speed. CMGs are also far more power efficient. For a few hundred watts and about 100 kg of mass, large CMGs have produced thousands of newton meters of torque.
Figure 1 Hard wheel rolling on and deforming a soft surface, resulting in the reaction force R from the surface having a component that opposes the motion. (W is some vertical load on the axle, F is some towing force applied to the axle, r is the wheel radius, and both friction with the ground and friction at the axle are assumed to be negligible and so are not shown.
The reaction force on the wheels result in sliding friction. The coefficients for these equations are determined with experiments by measuring the tractive effort from the locomotive at different constant speeds or with a coasting experiments (the rail vehicle is set in motion at a certain speed and then the traction is disengaged, causing the ...
Diagram of a gyro wheel. Reaction arrows about the output axis (blue) correspond to forces applied about the input axis (green), and vice versa. A gyroscope is an instrument, consisting of a wheel mounted into two or three gimbals providing pivoted supports, for allowing the wheel to rotate about a single axis. A set of three gimbals, one ...
The slew of 3-axis stabilized spacecraft is typically in closed loop control with thrusters or electrically-powered reaction wheels maintaining or altering the craft's attitude based on sensor measurements. A typical example is a space telescope that should be turned to observe a new celestial object.
The construction of a magnetorquer is based on the realization of a coil with a defined area and number of turns according to the required performances. However, there are different ways to obtain the coil; thus, depending on the construction strategy, it is possible to find three types of magnetorquer, apparently very different from each other but based on the same concept: [1]
Likewise, the spinning wheels of a vehicle attempt to slide backward across the ground. If the ground is not too slippery, this results in a pair of friction forces: the 'action' by the wheel on the ground in backward direction, and the 'reaction' by the ground on the wheel in forward direction. This forward force propels the vehicle.