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The poles can be varied at a ratio of 1:2 and thus the speed can be varied at 2:1. [ 7 ] [ 8 ] [ 9 ] Normally, the electrical configuration of windings is varied from a delta connection (Δ) to a double star connection (YY) configuration in order to change the speed of the motor for constant torque applications, such as the hoists in cranes .
Typically, the voltage is controlled by reverse-parallel-connected silicon-controlled rectifiers , but in some circumstances with three-phase control, the control elements can be a reverse-parallel-connected SCR and diode. [2] [3] Another way to limit motor starting current is a series reactor. If an air core is used for the series reactor then ...
Another way of changing speed of a direct current motor is to change the voltage applied to the armature. An adjustable-speed motor drive might consist of an electric motor and controller that is used to adjust the motor's operating speed. The combination of a constant-speed motor and a continuously adjustable mechanical speed-changing device ...
Free-body diagram of a U-channel synchronous linear motor. The view is perpendicular to the channel axis. The two coils at centre are mechanically connected, and are energized in "quadrature" (meaning a phase difference of 90° (π/2 radians) between the flux of the magnets and the flux of the coils). The bottom and upper coils in this ...
The universal motor is modified in several ways to allow for proper AC supply operation. There is a compensating winding typically added, along with laminated pole pieces, as opposed to the solid pole pieces found in DC motors. [2] A universal motor's armature typically has far more coils and plates than a DC motor, and hence fewer windings per ...
Google planned to operate Motorola Mobility as an independent company. [17] In a post on the company's blog, Google CEO and co-founder Larry Page revealed that Google's acquisition of Motorola Mobility was a strategic move to strengthen Google's patent portfolio. At the time, the company had 17,000 patents, with 7,500 patents pending.
During the start-up a typical rotor has 3 poles connected to the slip ring. Each pole is wired in series with a variable power resistor. When the motor reaches full speed the rotor poles are switched to short circuit. During start-up the resistors reduce the field strength at the stator. As a result, the inrush current is reduced. Another ...
Typically, given a phase, the center tap of each winding is made common: three leads per phase and six leads for a typical two phase motor. Often, these two phase commons are internally joined, so the motor has only five leads. The 28BYJ-48, accompanied by a ULN2003 driver, is one of the most popular stepper motors among hobbyists.