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The electrical power consumption in automobiles continues to increase thereby demanding higher power capability of the alternator. The standard alternator today is a claw-pole synchronous machine. The claw-pole alternators have brushes which are maintenance issue; it is not possible to increase power output by increasing the stack length; and the rotor inertia is large due to the steel core and rotor excitation coil. Despite these disadvantages, the claw-pole alternator is still used because of its low cost and ease of manufacturing. An alternator with DC stator excitation, has a laminated salient pole rotor with no excitation coil. Therefore the weight and inertia is less than in the claw-pole alternator. The excitation coil is located in the stator and therefore there are no brushes needed. In this type of alternator, the stator has three-phase output coils evenly shifted in space 120 degrees.

The performance and property of brush-less car alternator with gap flux controlled by DC stator coil is discussed in this paper. This type of alternator is more dependable, has reduced weight and dimension of rotor compared with traditional alternators. Reduction of the rotor weight is obtained by elimination of rotor coil and reduction of steel core weight. The stator steel core is laminated and exactly like ordinary stator core, but coils are different. There are three phase stator coils and coil for DC excitation. Salient multi poles rotor is laminated and does not contain any coils This paper presents theoretical discussion of principle of operation of this type of machine. Traditional alternator was modified for physical modeling. Results of this modeling are presented as well.

The main feature of the described sensor is its contact-less construction. The lack of contacts on the moving rod increases reliability of the sensor. The sensor comprises the core with the short - circuited two - layer secondary winding. In addition, the sensor is provided with the two multilayer windings, the first being the long primary winding, the second one is the short output winding. The output signal is induced on the output winding. In order to produce the output signal, the alternating voltage with frequency of 20…50 kHz is applied to the primary coil. Depending upon the core position of the short-circuited winding, the current of various values will be induced, which causes various voltages to be induced on the output winding. The position of the core may vary in range 0...40 mm. The range can be modified in a particular construction. The output characteristics of the sensor are roughly linear.