the advancement in spacecraft related research. The purpose of this essay is to explain what a railgun is and how it works along with a little history and the recent advancements in railgun related science. 3 1. What a railgun basically is A railgun is an electrically powered electromagnetic projectile launcher and a large electric circuit, made up of three parts: a power source, a pair of parallel rails and a moving armature. Along the pair of parallel conducting rails a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail. Railguns have long existed as experimental technology but the mass, size and cost of the required power supplies have prevented railguns from becoming practical military weapons. However, in recent years, significant efforts have been made towards their development as
The electromagnetic torque is born in air gap. The torque is proportional to the current in dc motor. Which equations are correct? P = sW; oomega = tuletis fii'st The angular frequency is 2*pi()*n / 60 ja 2*pi()f The motor torque is equal to TL + J * oomega tuletis aja järgi The inductor supplies the motor with flux. The leading companies in the world market of electrical drive engineering are: Mitsubishi. The energy balance is described by energy conservation law. The armature supplies the motor with current. The cheapest and the most reliable is induction motor. The torque production is the result of interaction of current - flux. The mechanical torque as compared to the electromechanical torque is ?? The source of the magnetic flux of the motor is DC or permanent magnet. The most suitable for the speed control is synchronous servo motor. Efficiency of the electrical drive is the power ratio of load to supply. Electromagnetic efficiency is measured in tesla.
in both cases ~10% [%] 0.55 0.5 0.27 0.2 No 76% 5 8 noticable change in efficency in both cases. 5. Experimental traces Graph 1 Mechanical power and Torque as a function of speed Graph 2 Armature current power and armature voltage as a function of speed Graph 3 Armature current and efficency as a function of Torque 6. U/f characteristic With boosting Without boosting 7. Solutions of the problems 4.1 How much are the nominal and maximal currents of the drive? Explain the difference of nominal and experimental current data. From nameplate, we get that the nominal currents are 1,7 / Y 1,0A. From the
· Which equations are correct P=sW · The angular frequency is 2n/60 2f · The motor torque is equal to P/ TL + Jd/dt · The cheapest and the most reliable is induction motor · The torque production is the result of interaction of current flux · Efficiency of the electrical drive is the power ratio of load to supply · The best electrical drive has efficiency very high · The torque is proportional to the current in dc motor · The inductor supplies the motor with flux · The armature supplies the motor with current · The mutual motion of the stator and rotor windings result in counter-EMF · If the angular frequency of the stator field is 300, how much the synchronous speed of the 2-pole motor will be 300 · The characteristics of the rigid drive is rigid · The rigidity of the high-efficient electrical drives is high · The standard supply grid has the oscillation period of 20 ms · Select the components that belong to the servo drive position sensor
13. Name the scientists who developed the induction machines. 14. Name the leading companies in the world market of electrical drive engineering. 15. What law describes the energy balance? 16. What equations connect power with energy? 17. Write the relations between the speed and angle, velocity and path. 18. What is the relation between the angular frequency and the rotational speed? 19. Write the major motor torque equation. 20. The inductor supplies the motor with what? 21. The armature supplies the motor with what? 22. In what part of the electrical drive is the electromagnetic torque born? 23. What variables interaction results in the torque production? 24. Compare the values of the mechanical and electromagnetic torques. 25. What is the source of the magnetic flux in the motor? 26. In what kind of motors the torque is proportional to the current? 27. What kind of motors is the cheapest and the most reliable? 28
the state of charge of the battery. Use a 11 While charging the battery note that the into engagement with the flywheel ring gear before the starter motor is energised. Once the hydrometer to make the check and compare temperature of the electrolyte should never engine has started, a one-way clutch prevents the results with the following table. exceed 37.8°C (100°F). the motor armature being driven by the engine Ambient temperature: Maintenance-free battery - until the pinion disengages from the flywheel. charging Further details of the various systems are Above 25ºC Below 25ºC given in the relevant Sections of this Chapter. Fully charged 1.210 to 1.230 1.270 to 1.290 12 This battery type takes considerably
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