Document 4v2Gr13QyKGdKD3NgZzogzZOQ

862 CHAPTER 39 1951 Guide Be Arranged for {vertfcS^} Mountin6 and Shall Be Provided with "(Open,' Splashproof, etc!) ` ^ f EnClSUre' NBMA {o b} Nation, and {sleeve} Bearing3- Specification G. Typical Specifications fob Squirrel-Cage Motor Conthol Control for Squirrel-Cage.................................Motors Shall Consist of an Enclosed (Fan, Pump, etc.) {Magnetic} Type {Reduced Volto|e} Starter Providing Overload Protection and Low Voltage {{please*011}* Control Shall Include a Safety Disconnect Switch {^^"'osure} ^ the Starting Controller. Specification H. Typical Specifications fob Wound Rotor Motor Control Control for Wound Rotor Motor Control for .. Applications Shall Consist of a Safety (Fan, Pump, etc.) Disconnect Switch, a Mounted Across the Line Starter Providing Over- load Protection, Low Voltage {^`ion}, and a Secondary {l^^gulating} Controller for /Separate Mounting \ t> .,, , ., (Mounting in Sam! Enclosure/' Pnmary and Secondary Control Shall Be Interlocked so as to Provide Complete Control from the Rheostat Handle. Specification I. Typical Specifications for Synchronous Motor Control Synchronous Motor Control for................................ Motors Shall Provide for (Application) {iteduled4Voltage} Starting and ShaI1 Be {se^i^^tfc}' (Educed Voltage (Autotransformersl Resistors 1- and Shall Limit Reactors J the KVA Inrush to a Maximum of---- Percent of Full Load KVA.) The Control Panel Shall Be for {Aboard} and Shall Be. of {g^S^} Construction. It Shall Provide Overload, Under Voltage Protection and After Pull- ing Out of Step Will ^chronixe} the Motor. Motors and Motor Controls 863 Specification J. Ttpicai. Specifications fob Single Phase Motor Control Control for Single Phase ........................................... Motors Shall Consist of a (Fan, Pump, etc.) {Magnetic} TyPe {Educed VoUag^} Starter Providing Overload Proteetion (and Low Voltage); and a Separate Safety Disconnecting Switch. GLOSSARY General Definitions NEMA is the abbreviation for the National Electrical Manufacturers Association. ABIC 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 percent 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 5J26 percent. Slip (a-c induction motors) is the difference between the motor speed and syn chronous speed expressed in percent of synchronous speed, e.g.t a 1200 rpm motor operating at 1140 rpm would nave a slip of 5 percent. 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 case 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 having 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 ticles tailing on the machine at any angle not greater than 15 deg from the vertical, cannot enter the machine either directly or by striking and running along a hori zontal or inclined surface. Splash Proof motors (50 C rise) are so constructed that drops of liquid or solid particles falling on the machine or coming toward it in a straight line at any angle not greater than 100 deg from the vertical, cannot enter the machine either directly or by striking and running along the surface. Totally Enclosed Non-Ventilaled motors (55 C rise) are so constructed as to prevent exchange of air between inside and outside of the case, but are not air tight and are not equipped with external cooling means. Totally Enclosed Fan-Cooled motors (55 C rise) are similar to totally enclosed, non-, ventilated machines, except that exterior cooling is provided by means of a fan or fans integral with the machine. Explosion Proof motors (55 C rise) have an enclosing case designed to withstand an explosion of a specified gas or vapor which may occur within it, and to prevent the ignition of the gas or vapor surrounding the motor by sparks, flashes, or explosions of the gas or vapor which may occur within the machine casing. Dust Explosion Proof motors (55 C rise) have an enclosing case designed and con-