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What process takes place in an electric machine when stationary is kept in a time-varying field?
Answer: b Explanation: Transformer emf is produced when the coil is stationary and flux varies with time. No energy conversion takes place in this process thus, only energy transference takes place. This kind of emf is generated in the transformer.
Answer: b
See lessExplanation: Transformer emf is produced when the coil is stationary and flux varies with time. No energy conversion takes place in this process thus, only energy transference takes place. This kind of emf is generated in the transformer.
Which of the following is used to connect the armature conductors to the commutator?
Answer: c Explanation: A commutator helps in rectifying the alternating current that is induced in armature. A riser is used to connect the armature conductors to the commutator. Riser segments are made of copper strips in a large machine.
Answer: c
Explanation: A commutator helps in rectifying the alternating current that is induced in armature. A riser is used to connect the armature conductors to the commutator. Riser segments are made of copper strips in a large machine.
See lessWhich part of an electric machine is designed to give the main magnetic flux?
Answer: c Explanation: Main poles is the part of an electric machine that is designed to give the main magnetic flux. This is present in the field system of the dc machine which is responsible to produce magnetic flux for the necessary excitation.
Answer: c
Explanation: Main poles is the part of an electric machine that is designed to give the main magnetic flux. This is present in the field system of the dc machine which is responsible to produce magnetic flux for the necessary excitation.
See lessWhy are tapered interpoles used in large DC electric machines?
Answer: a Explanation: At heavy overloads saturation at the root of the pole may occur. Thus, tapered interpoles are used to eliminate saturation at root of the pole.
Answer: a
Explanation: At heavy overloads saturation at the root of the pole may occur. Thus, tapered interpoles are used to eliminate saturation at root of the pole.
See lessWhat kind of layer winding does a closed winding of an electric machine usually have?
Answer: b Explanation: A double layer winding has identical coils where one coil side of each coil lies in the top half portion of slot and another side on the bottom half of another slot. Such a winding is used to make closed winding.
Answer: b
Explanation: A double layer winding has identical coils where one coil side of each coil lies in the top half portion of slot and another side on the bottom half of another slot. Such a winding is used to make closed winding.
See lessWhat is the other name for a short-pitched coil electrical machine?
Answer: d Explanation: Two coil sides can form a full pitched coil when they are spaced one pole pitch apart. A coil span less than a pole pitch is called a short-pitched coil or chord.
Answer: d
Explanation: Two coil sides can form a full pitched coil when they are spaced one pole pitch apart. A coil span less than a pole pitch is called a short-pitched coil or chord.
See lessWhich of these factors does not determine the specific magnetic loading in rotating machines?
Answer: d Explanation: The Magnetizing current, Core loss, and Maximum flux density in iron parts of the machine are the factors that help in determining the specific magnetic loading in rotating machines.
Answer: d
Explanation: The Magnetizing current, Core loss, and Maximum flux density in iron parts of the machine are the factors that help in determining the specific magnetic loading in rotating machines.
See lessWhere does maximum flux density occur in a well-designed electric machine?
Answer: c Explanation: The maximum flux density in a well-designed electric machine occurs in the teeth of the machine. The flux density in teeth is directly proportional to the specific magnetic loading.
Answer: c
Explanation: The maximum flux density in a well-designed electric machine occurs in the teeth of the machine. The flux density in teeth is directly proportional to the specific magnetic loading.
See lessHow should be the specific loadings to design a machine with reduced dimensions?
Answer: a Explanation: The output coefficient is proportional to the product of specific magnetic loading and specific electric loading. The output coefficient of a rotating electric machine is inversely proportional to the output coefficient. Thus, increased values of specific loadings will give aRead more
Answer: a
Explanation: The output coefficient is proportional to the product of specific magnetic loading and specific electric loading. The output coefficient of a rotating electric machine is inversely proportional to the output coefficient. Thus, increased values of specific loadings will give a small size machine.
See lessHow should be the output coefficient of a rotating electric machine from an economics point of view?
Answer: a Explanation: The rotating electric machine designed with a higher output coefficient will have a smaller size and lesser cost. This volume of active parts of the machine varies inversely with the output coefficient. Thus, the output coefficient of a rotating electric machine must be high.
Answer: a
Explanation: The rotating electric machine designed with a higher output coefficient will have a smaller size and lesser cost. This volume of active parts of the machine varies inversely with the output coefficient. Thus, the output coefficient of a rotating electric machine must be high.
See less