The question asks about the purpose of 'fullering' in a forging operation. Fullering is a specific forging technique used to alter the shape of a workpiece. We need to identify which of the given options correctly describes this operation.
Correct Option: A) Draw out the material
The question asks to identify which of the given options is NOT a fusion welding process. To answer this, we need to understand the fundamental difference between fusion welding and non-fusion (or solid-state) joining processes, and specifically, how brazing differs from the other listed options.
C) Brazing is not a fusion welding process. In brazing, only the filler metal melts and flows into the joint by capillary action, while the base metals remain solid. This distinguishes it from fusion welding, where the base metals themselves are melted.
The question asks about the type of articles typically cast using the centrifugal casting method. Centrifugal casting utilizes centrifugal force to distribute molten metal in a rotating mold. Understanding the mechanics of this process helps determine the suitable shapes for casting.
B) Symmetrical shape about horizontal axis. True centrifugal casting, where the mold rotates about a horizontal axis, is widely used for producing hollow cylindrical articles like pipes, tubes, and bushings. These articles are symmetrical along their longitudinal (horizontal) axis. Semi-centrifugal casting, which uses a vertical axis, produces articles symmetrical about that vertical axis, but the horizontal axis application is a very prominent use of the technology.
The question asks about the primary purpose of jigs and fixtures in manufacturing. Jigs and fixtures are essential tools used in various machining and assembly operations. Understanding their fundamental role will help identify the correct option.
A) Increase machining accuracy. Jigs and fixtures are primarily used to hold the workpiece and/or guide the tool, thereby ensuring that machining operations are performed precisely and consistently, leading to higher accuracy in the manufactured parts. This is their most direct and fundamental purpose.
Directional relays are crucial protective devices in power systems. They are designed to operate only when the fault current flows in a specific direction. This directionality is determined by comparing the phase angle of the fault current with a reference voltage. The product of voltage and current, along with their phase angle, defines power. Therefore, the relay essentially senses the direction of power flow.
A) power — Directional relays are fundamentally based on sensing the direction of power flow. They achieve this by analyzing the phase relationship between the voltage and current, which together define the direction of power.
The question asks about the energy conversion that takes place in a fuel cell. Understanding the basic principle of how a fuel cell operates is key to answering this question.
D) chemical — Fuel cells are electrochemical devices that directly convert the chemical energy stored in fuels (like hydrogen) and oxidizers (like oxygen) into electrical energy. This process involves redox reactions where electrons are transferred, generating an electric current.
The question asks about the typical operating head range for a Francis turbine. To answer this, we need to recall the characteristics and applications of different types of hydraulic turbines, specifically Francis, Pelton, and Kaplan/Propeller turbines, based on their head and flow rate suitability.
A) medium heads. The Francis turbine is a mixed-flow reaction turbine that is most efficiently used for medium heads and medium flow rates. Its design allows it to adapt to a significant range of heads, but its primary application is in the medium head category.
The question asks to identify the specific name for the angle between the rotating stator flux and the rotor poles in an electrical machine, typically a synchronous machine. This angle is crucial for understanding torque production and stability.
A) torque angle — This is the correct term for the angle between the rotating stator flux and the rotor poles. It directly relates to the electromagnetic torque developed by the machine.
The question asks to identify the type of motor commonly used in tape recorders. This requires knowledge of the characteristics of different motor types and their applications, especially where smooth, constant speed operation and low noise are critical.
Correct Option: A) Hysteresis motor is used in tape recorders because of its extremely smooth and quiet operation, constant synchronous speed, and lack of mechanical vibrations, which are crucial for high-fidelity audio reproduction.
The question asks about the material used for slip rings in induction motors. Slip rings are crucial components in wound-rotor induction motors, allowing external resistance to be connected to the rotor circuit. The material chosen for slip rings must possess specific electrical and mechanical properties to ensure efficient and reliable operation.
Correct Option: D) phosphor bronze