Document 9JwD6DbgdGj96xkrNYby12OL3

840 CHAPTER 39 1950 Guide of Developing a Starting Torque of ....... Per Cent Full Load Torque, a Pull-In Torque of......... Per Cent Full Load Torque, and a Pull-Out Torque of ............ Per Cent Full Load Torque. The Motor Field Shall Be Excited from a rDirect Connected Exciter' Belted Exciter M-G Set Exciter I Which |Shall Shall 1 Not/ Be Included with the Motor. d-c Bus J Specification F. Typical Specifications fob Single Phase Motobs ................Hp,................. RPM, jgjjj Cycles, jjgoj Volte, Single Phase Motor of the....,................................ Type for Driving ......... .................... Motor Shall (Capacitor, Split Phase, etc.) (Application) Be Arranged for {vertical^} Mounting and Shall Be Provided with a............... ............................Type of Enclosure; NEMA 4) Insulation, and (Open; Splashproof, etc.) lUass {lleeve} ?earinBa- _______________ Specification G. Typical Specifications fob Squibbel-Cage Motob Contbol Control for Squirrel-Cage ................................Motors Shall Consist of an Enclosed (Fan, Pump, etc.) {Magnetic} ^P6 {^du^ed Voltage} Starter Priding Overload Protection and Low Voltage Control Shall Include a Safety Disconnect Switch {g^cS^^sUre} with the Starting Controller. Specification H. Typical Specifications fob Wound Rotob Motob Contbol Control for Wound Rotor Motor Control for .. Applications Shall Consist of a Safety (Fan, Pump, etc.) . Disconnect Switch, a {common Mounted Across the Line Starter Providing Over load Protection, Low Voltage and a Secondary {l^dRegulating} Controller for |^^^aj^^Ug^J'Eng]oaurej. Primary and Secondary Control Shall Be Interlocked so as to Provide Complete Control from the Rheostat Handle. Specification I. Typical Specifications fob Synchbonous Motob Contbol Synchronous Motor Control for................................... Motors Shall Provide , for (Application) {R^duled1,Voltage} St"tirig and Sha11 ^ {I^i-Nte^tic}- (Reduced Voltage Motors and Motor Controls 841! .' [Autotransformers'l '. Starting Shall Be Obtained by Means of j Resistors and Shall Limit [Reactors " the KVA Inrush to a Maximum of___Per Cent of Full Load KVA.) The Control Panel Shall Be for {Aboard} Assembly and Shall Be of Cubfcle*1} -Construction. It Shall Provide Overload, Under Voltage Protection and AfterPiilling Out of Step Will {i^^tically ITM^ni"} theMtor' Specification J. Typical Specifications fob Single Phase Motob. Contbol Control for Single Phase.............................................. Motors Shall Consist , of a (Fan, Pump, etc.) {Magnetic} Type VouTge) Starter Providing Overload-Protection:(and Low Voltage); and a Separate Safety Disconnecting Switch, . ... ./, GLOSSARY General Definitions NEMA is the abbreviation for the National Electrical Manufacturers Association'. AEIC.is the abbreviation for the Association of Edison Illuminating Companies. EEI is the abbreviation for the Edison Electric Institute. Speed Regulation (d-c motors) is the change in speed between no-load and full-load, expressed in per cent of full-load speed; for example, a motor having a no-load speed of 1200 rpm and a full-load speed of 1140 rpm would have a speed regulation of 5.6 percent. . Slip (a-c induction motors) is the difference between the motor speed and syn chronous speed expressed in per cent of synchronous speed,, e.g., a 1200 rpm .motor operating at 1140 rpm would have a slip of 5 per cent. Torque is an expression of the turning effort developed by, the motor at the shaft, and is usually expressed in ounce-feet for fractional horsepower motors, and in poundfeet for motors of larger ratings. Primary is the term usually applied to the high voltage or line side of a transformer or motor. In the ease of the wound rotor motor the primary is the stator winding. Secondary is the term usually applied to the low voltage or load side of a trans former or motor. In the case of the wound rotor motor the secondary is the rotor winding. NEMA Classification of Motor Enclosures Open motors (40C rise, rated load, .50 C rise, service factor load) are self-ventilated machines haying no-restriction to ventilation other than that, necessitated by me-' chanical construction. Protected motors (50 C rise) have all ventilating openings in the frame protected by perforated covers. , . , . ' .: Semi-Protected motors (50 C rise) have the ventilating openings in the top half of the frame only protected by perforated covers. , Drip Proof motors (50 C rise) are so constructed that drops of liquid or solid par-. tides falling on the machine at any angle not greater than 15 deg from the'vertical, cannot enter the machine either directly of by striking and running along a hori- sontakor.inclined surface. ,, ' Splash Proof motors (50 C rise) are so constructed, that- drops~ofliquid ofsolid particles falling on the machine or comiDg towards it in a straight line at any angle