CSA C22 2 NO 73-1953 Construction and Test of Electrically Equipped Machine Tools (Second Edition General Instruction No 1 August 1953).pdf

1、C22.2 No. 73-1953(reaffirmed 2013)Construction and test of electrically equipped machine toolsLegal Notice for StandardsCanadian Standards Association (operating as “CSA Group”) develops standards through a consensus standards development process approved by the Standards Council of Canada. This pro

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15、sLOADTHISDOCUMENTONTOACOMPUTERFORTHESOLEPURPOSEOFREVIEWINGITsSEARCHANDBROWSETHISDOCUMENTANDsPRINTTHISDOCUMENTIFITISIN0$ (b) The mechanical features of machine tools, except as these affect the electrical equipment used in connection with such machines; (c) Woodworking machines ;* (d) Portable electr

16、ic tools (e.g., drills, hammers, etc.) covered in the latest issue of Specifica- tion C22.2 No. 71, “Portable Electric Tools“; (e) Welding or gas-cutting machines. *Machjps used for both woodworl?ing and metalworking are required to comply with this Specification and also with any special requiremen

17、ts for woodworking machines. NorrE: The Approvals Laboratories will, at its discretion, use this Specification in the approval of other types of ma- chines not specifically covered by other individual Specifi- cations of Part II of this Code insofar as its requirementt may be aJ4hcable. USE Us. 2. F

18、or general industrial use. 8 CSA SPECIFICATION C22.2 No. 73 SPECIFICATION DETAILS GENERAL REQUIREMENTS General 3. See the latest issue of Specification C22.2 No. Requirement! 0, “Definitions and General Requirements“; applic- able to all Specifications of Part II of this Code. Other references herei

19、n to that Specification are ab- breviated to “Specification C22.2 No. 0“. Ncnt: Throughout this Specification reference is made to certain other Specifications which should be consulted. A list of these Specifications appears on page 6. CONSTRUCTION General 4. Component parts of electrical equipment

20、 shall be of types specifically approved for the use intended or shall be approved with, and as anintegral part of, the machine. 5. Approval of component parts as a part of a machine shall not be regarded as acceptance of such parts for general use or necessarily for use with any machine other than

21、that for which the approval has been granted. Installation 6. Electrically equipped machine tools shall be so constructed that the rules for the installation and use of the electrical equipment, as set forth in Part I of this Code, may be readily complied with. 7. Electrical equipment on machine too

22、ls shall be so located, guarded or enclosed as to provide adequate protection for such equipment during all normal operation of the machines. Acces8ibility 8. Electrical equipment which will require serv- icing or maintenance shall be made accessible for such work without the necessity of dismantlin

23、g any of the mechanical parts of a machine. This does not preclude the removal of a cover plate. Enclosures 9. If electrical equipment is mounted on the back of doors or cover plates, the doors or cover plates shall either be hinged or the complete assembly shall be readily removable as a unit. The

24、construction shall be such as to place no strain on leads or connections or subject them to abrasion when the cover is removed or the unit is withdrawn. If the weight of cover plate and attached equipment is in excess of 5 pounds, means shall be provided to support it in the withdrawn position. ELEC

25、TRICALLY EQUIPPED MACHINE TOOLS 10. Electrical equipment shall be housed in enclo- sures affording proper protection for the equipment against the action of oil, moisture, dust, or other injurious materials which may be encountered in the normal operation of the machine. Enclosures which are mounted

26、 on or in the machines, shall not be open to floors or to foundations on which the machines rest. Doors and cover plates shall be provided with suitable means for fastening them securely in the closed position; and in the case of removable cover plates, these means shall be such as to require the us

27、e of tools or keys to open them. Nois: Necessary enclosures for electrical equipment may be partly or wholly provided by the frames or other com- ponents of machines. See also the latest issues oj the following Specifications: C222 No. 4, Enclosed Switches“; C222 No. 11, “Fractional-f-f orsepower El

28、ectric Motors for Other than Hazardous Location.?; C222 No. 14, “Industrial Control Equipment for Ordi- nary (Non-hazardous) Locations“; and C22.2 No. .54, “Integral-Horsepower Electric Motors for Other than Hazardous Locations“. 11. Enclosures for use under the provisions of Clause 20(b) shall comp

29、ly with the following: (a) The wall thickness shall be not less than No. 14 U.S. sheet-metal gauge if of sheet steel, not less than %2 inch if of malleable iron, or not less than 38 inch if of other cast metal; (b) The thickness of cover plates shall not be less than that specified for walls; (c) If

30、 enclosures consist of cavities in machine bases or frames and are restricted in volumes to the approximate size of the electrical equip- ment contained, they shall have clear open- ings of at least 2 square inches, vented to other compartments within the machines which shall have volumes equal to a

31、t least one-half of the volumes of the enclosures, and which shall be free from any accumulation of oil, grease, or other flammable material. 12. Adequate spacings between bare live parts of opposite polarity, and between bare live parts and metal parts which may be grounded, shall be pro- vided. CS

32、A SPECIFICATION C22.2 No. 73 NOTE: See also the latest irsues of the following Specifications: C222 No. 4, “Enclosed Switches“; C222 No. 11, “Fractional-Horsepower Electric Motors for Other than Hazardous Locations“; C222 No. 14, “Industrial Con trol Equipment for Ordi- nary (Non-hazardous) Location

33、s“; and C22.2 No. 54, “Integral-Horsepower Electric Motors for Other than Hazardous Locations“. Connection 13. Supply-circuit connections shall be provided to Supply in accordance with the requirements of Specification Circuit C22.2 No. 0. There shall be not more than one such point of connection on

34、 a machine for each separate source of supply. If more than one source of supply is necessary*, the several connections shall be group- ed at one point, or, alternatively, dual-voltage relays may be provided to ensure the simultaneous discon- nection of all sources of supply. Supply circuit con- nec

35、tions shall be readily accessible. * It is strongly recommended that only one source of supply be used on a machine and that sources of control tower be obtained by the use of transformers or rectifiers supplied as part of a machine. Supply 14. If a manually-operated disconnecting means Circuit (e.g

36、., a switch or circuit breaker) is mounted on a Disconnecting machine to isolate the supply circuit, it shall open all ungrounded conductors of the circuit simulta- neously. 15. Such disconnecting means shall be readily accessible unless they are designed for isolating purposes only and are not capa

37、ble of successfully opening the circuit under load, in which case they shall be rendered inaccessible to unauthorized per- sons. The “off“ position shall be clearly indicated. 16. If more than one such disconnecting means is provided for multiple supply circuits, they shall be grouped at one point.

38、17. If an enclosed switch is used as a disconnect- ing means and if any part of the load is a motor load, a motor-circuit switch shall be used, unless the total load of the circuit is greater than the rating of the largest motor-circuit switch available, in which case the switch shall be treated as

39、an isolating switch in accordance with the requirements of Clause 15. Fiaes 18. If fuses are provided for the protection of internal wiring and equipment they shall be located in one compartment or enclosure. They shall be ELECTRICALLY EQUIPPED MACHENS TOOLS 11 accessible only through doors or cover

40、 plates held closed by means requiring the use of a tool or key for opening, and the doors or cover plates shall be marked with cautions reading “Disconnect machine from the electrical supply before opening“, or equi- valent wording may be used. Motors 19. Motors shall be of adequate capacity and sh

41、all be of types recognized as suitable for their parti- cular application. Norz: See also the latest issues of the following Specifications. C222 No. 11, “Fractional-Horsepower Electric Motor: for Other than Hazardous Locations“; and C22.2 No. 54, “Integral-Horsepower Electric Motor: for Other than

42、Hazardous Locationc“. Motor 20. Motor-control equipment shall conform to the Control following: (a) Motor-control equipment shall be of types re- cognized as suitable for their particular appli- cation and shall be capable of satisfactory performance under the starting conditions and duty cycles of

43、the motors with which they are used. (b) Motor-control equipment not specifically ap- proved for group fusing may be grouped on a branch circuit provided both of the following conditions are complied with: (i) The branch circuit overcurrent protection shall be of a rating or setting not greater than

44、 300 percent of the full load current rating of the largest motor of the group plus the sum of the full load current rat- ings of all the other motors in the group which may be in operation at one time, but in no case more than: 200 amperes at 250 volts or less, and 100 amperes at vol- tages between

45、 251 and 750. (ii) All contacts which open motor primary circuits shall be enclosed in one or more enclosures which may be built into or form part of the machine frame or base or be mounted on the machine or on the floor or wall adjacent to the machine, and which comply with the requirements of Clau

46、se 11. (c) Motor-control equipment not conforming with (b) above for circuit protection or en- closure, 2 CSA SPECIFICATION C22.2 No. 73 shall be of types approved for group fusing if it is intended to group controls under the pro- tection of a single set of overcurrent devices rated or set at more

47、than 15 amperes. NOTE: See also the latest issue of Specification C22.2 No. 14, “Industrial Control Equipment for Ordinary (Non-ha- ardous) Locations.“ Low-Voltage 21. Low-voltage protection shall be provided for Protection all motors the unintentional starting of which would be liable to create a h

48、azard. Overload 22. Each motor shall have individual overload pro- Protection tection except for the following cases where it may be dispensed with: (a) A motor rated at 1 horsepower or less, having a manual starter, and where it may be readily determined from the starting position that the motor is

49、 running, if the motor is on an individ- ual branch circuit or if it is on a branch cir- cuit supplying a group of motors having overcurrent protection rated or set at not more than 15 amperes; or (b) A motor whose operating requirements are such that it is impracticable to obtain proper overload protection, if the motor is on a branch circuit having proper overcurrent pro- tection as specified in the latest iss