【正文】 10. What markings would you expect to find on apparatus certified for use in potentially hazardous atmosphere under CENELEC standard EN 50018 (Flameproof enclosure ‘d’).EExdEuropean Electro technical Standardization Committee 歐洲電工技術標準化委員會Questionnaire and Answer Sheet: ROTATING EQUIPMENT 1 旋轉設備 11. What do you look for when inspecting fir tree slots in rotor discs of a gas turbine?The edges are rounded an there are no cracks.2. What do you consider a normal acceptable vibration limit for a large gas turbine (RPM 3 to 4 thousand)?.001” to .002” 英寸到 英寸3. How is the acceptance of fir tree dimensions of blades and rotor discs determined in a gas turbine?Plug gauge and / or optical parator.4. Is it necessary to clean the steam chest prior to running a steam turbine? If so why?Yes, otherwise nozzles and blading could be damaged.5. Name two methods of carrying out the NPSH (or suppression) test.Page 11 of 61? Vacuum tank, varying the liquid level of suction 、變化液體水平的吸入罐? Heat the water 加熱水? Throttle the 6. What roughness (surface finish) is required on the gear tooth surface?32 RMS or better on 90% of the tooth length as measured along the pitch line.7. After a pump is mounted on a base plate, what dimensions should be checked before shipping?? Anchor bolt hole ? Nozzle locations and 8. What types of tests / inspections / checks are usually made on centrifugal pumps?Material check, clearance checks, hydrostatic test, performance test, NPSH or suppression test, internal examination and dimensional examination.9. What is the minimum length of time the pressure should be held during the inert gas test of the casing?30 minutes. 30 分鐘10. How is the hydro test pressure determined for a pressor casing?. times the maximum design pressure for the casing.對于套管是 倍的最大設計壓力。6. In what state are relay contacts shown on normal relay circuit diagrams?De energised (Shelf condition).7. How would you start a visual inspection of a control panel at a manufacturers premise? What are the salient points before starting detailed testing?Check the panel against . specifications, drawings and manufacturers standards, for pliance.8. What is meant by “first out” or “first alert” when applied to an annunciator sequence?First out feature is a means of identifying the first of a group of related or interactive alarm inputs to go into alarm state.9. In 1976, IEC Publication 529, Classification of Degrees of Protection provide by enclosures was issued. This document bines the requirements of IEC 144 which specifies degrees of protection for enclosures for low voltage switchgear and control gear with those of IEC Degrees of Protection by enclosures for rotating machinery.An enclosure defined by these standards could be marked by the letters IP followed by two digits. What is the significance of these two digits?1st digit – Protection provided against persons.　第一個數(shù)字：防止人體接觸。6. What is the relationship between the phase voltage and the line voltage in a 3phase 4wire system?LV = x PV 線路電壓= x 相電壓7. Define magic centre, in a motor.The point where the magic pull on the rotor is the same in both axial directions.8. The temperature rise test of a motor is conducted:From a cold start until the temperature reaches a steady high at full load.9. Regarding safety, what would you consider the most important rules to observe when inspecting electrical equipment?During testing remain in the designated safe areas. Do not touch anything until you are certain it is deenergized.10. What determines the speed of the rotating field?Number of poles and frequency of RPM = sfreq x 60 每分鐘轉數(shù)=供給頻率60No. pairs of poles 磁極的對數(shù)11. What is some of the information the inspector can find in the appropriate cable standards?a) Conductor diameters, areas, resistance, stranding 纜芯直徑、范圍、電阻、繩股b) Insulation thickness 絕緣厚度c) Shielding, jacketing 防護物、護套d) Length of test samples 試驗樣品的長度e) Physical an aging requirements 自然老化條件12. Name the ponents you would expect to find in a switchgear assembly.Relays, Fuses, Meters, Transformers, Circuit Breakers, Bus Bars, Terminal Blocks, Terminal Switches, Indicating Lights.13. What are some of the production tests performed on transformers?Measurement of: Impedance, no load losses, winding resistance, winding ratio, insulation integrity, magizing or saturation tests, short circuit test.14. When a primary current injection test is required, it is acplished by:The correct answer is: 4 正確答案：4Page 9 of 61Applying high current with a low voltage tests source. 應用高電流和一個低電壓的源15. When a hand cranked megger is used to check most threephase induction motors, how many tests are required? Why?One. the motor windings are connected internally so a test on one lead checks the entire winding.16. When the quantity of cable being purchased is not sufficient, according to the standards, to require plete testing, what should the inspector do to ensure its quality?Witness the tests which are being conducted on his order and examine the vendor’s records of the latest plete test performed on this type cable.17. What is the purpose of a temperature rise or heat run test in a motor or transformer and how is it done?To check the temperature rise of the windings does not exceed the insulation rating. An accurate way to measure the temperature rise is to measure the change in resistance of the windings after running the equipment for a given period of time.18. How is the slip of a motor usually described or expressed?As a % or fraction of a synch speed.19. Define end float, in a motor.The axial movement of a rotor in a sleeve bearing motor.20. Name two locations in a Class 1, Division 1, Group D area where conduit seals are required by the NEC.In each conduit run entering an enclosure for apparatus which may produce arcs, sp