FORMULAS AND CALCULATIONS FOR MOTORS

 FORMULAS AND CALCULATIONS FOR MOTORS

Guidelines (Approximations)

 

·         A motor produces 3 lb. ft. per horsepower at 1800 rpm.

·         A motor produces 4.5 lb. ft. per horsepower at 1200 rpm.

·         A 3-phase motor requires 1 amp per hp at 575 volts.

·         A three-phase motor requires 460 volts and 1.25 amps per horsepower.

·         A 3-phase motor uses 2.5 amps per horsepower at 230 volts.

·         A single-phase motor uses 230 volts and 5 amps per horsepower.

·         A single-phase motor requires 115 volts and 10 amps per horsepower.

Machine Formulas

 

Torque in lb .ft  = HP x 5250
                                http://www.generatorjoe.net/html/reliance/images/4pxlblack.gif
                                     rpm

Conversion of Temperature

·         Deg C = (Deg F - 32) x 5/9

·          Deg F = (Deg C x 9/5) + 32

·          ºR = 1.8 K + 0.6

·         K = 5/9 (ºR-0.6º)

·          ºF = 1.8ºC + 32º

·         ºC = 5/9 (ºF-32º)

·          ºR = ºF + 460º

·         K = ºC + 273º  

C = Celsius, degrees,ºF = Fahrenheit, degrees,K = Kelvin,ºR = Rankine, degrees

 

  

 Inertia in pounds per square foot equals WK2 , the acceleration time in seconds.

T = Average Acceleration Torque in Lb. Ft.

AC motors' synchronized speed, frequency, and the number of poles

   

 

ns

120 x f/ P

f =

P x ns/120

  P =120 x f/ns

       Horsepower, torque, & speed about one another

  


Motor Stall 

% Slip =ns - n

              ------------

              ns x 100

Symbols

 

·         I equal current in amps.

·         E = volts of voltage

·         Kilowatts (kW) and kilo-volt-ampere (kVA) are power units.

·         HP stands for horsepower output.

·         n is the motor's revolutions every minute (RPM) speed.

·         RPM stands for revolutions per second or ns.

·         P is the number of poles.

·         CPS stands for cycles per second, or "f."

·         T is the torque in pounds-feet.

·         EFF is efficiency in decimal form.

·         The power factor in decimal form is PF.

Similar Inertia

All rotating components in mechanical systems typically don't spin at the same speed. Therefore, the "equivalent inertia" for every moving component at a specific speed of the prime mover must be determined.

The sum of the WK2 values for each component, expressed in terms of prime mover speed, represents the system's total equivalent WK2.

  WK2EQ = lb.ft2 rpm + 100 lb.ft2 + 3,000 lb.ft2Load

WK2EQ = 3200 lb.ft2

 The WK2, the prime mover, sees when traveling at its speed as the overall WK2 equivalent.

  

Torque accelerating

The amount of energy necessary for keeping the system operating is indicated by the comparable inertia of an adaptable speed drive. However, additional energy is needed to start or accelerate the mechanism.

 


Duty Cycles Sales Orders frequently have a notation made under special characteristics like:

"Appropriate for ten starts per hour,"


Comments

Post a Comment

Popular posts from this blog

Ac Motor Introduction operation and construction

Image
  AC Motor  An electric motor transfers electrical energy into mechanical energy. It serves as the link between a building's electrical and mechanical systems.  Any electrical system needs electric motors as a crucial component. They use around 64% of the electricity produced in factories, workplaces, and residences.    Principle of Motor Operation A magnetic field will be created across a wire loop with electrical current flowing through it. An additional magnet's field will cause this loop to rotate, creating a mechanically actionable force (torque).   Basic Components of an AC Motor Basic AC Motor Parts: The following are the fundamental components of AC motors: • Enclosure.  • Stator.  • Rotor.  • Bearings.  • Cable Box.  • Face Bolt.  Important Terms Enclosure A frame, a yoke, and two end brackets, sometimes called bearing housings, comprise the enclosure. The enclosure of a motor not only keeps the moto...
Read more

Conductor Ampacity p2

Image
 Terms for Insulation Materials Compound for CPE Jacketing made of chlorinated polyethylene. Ethylene Propylene Rubber is an ozone-resistant rubber composed of EPDM. Retardant to flames A substance that is added to insulation materials to reduce their flammability, like antimony oxide (in PVC) or aluminum tri hydrate. Flame Retardant A material's ability to prevent combustion from spreading at a slow rate of motion, preventing flame transmission. MTW Insulated by thermoplastic machine tool wire: 90 to 105 °C, 600 volts. Nylon A class of polyimide polymers used to coat wire and cables. Non-Polluting PVC A polyvinyl chloride composition without plasticizer migration, which causes electrical contamination. Polyester A high-strength, resistant-to-moisture material employed as a cable core wrap is made mostly from polyethylene terephthalate. Polyethylene A thermoplastic substance that is ethylene that has been polymerized. Polymer A material composed of several chemical units of molecul...
Read more

Test & answers of electrical-p3

Image
  Test & answers of electrical-p3 100. How pressure generates an electromagnetic field 101. How magnetism generates an electromagnetic field 102. What are the common objectives of those six EMF sources? 103. What do circuit breakers do? 104. Why is Individual Branch Circuits Important? 105. What are additional General Purpose Branch Circuits? 106. What Are Multi-wire Branch Circuits? 107. What exactly are Pull Box Dimensions? 108. The Minimum Box Length is calculated in what way? 109. Tell the total of all of the following measures to angle pulls. 110. What substance is used as wire insulation? 111. Do you realize the power your kitchen possesses? 112. What is the Energy Consumption? 113. Provide AWG industry value? 114. Why are fuses unaffected by voltage? 115. What are Ghost Loads, exactly? 116. What is the outside temperature? 117. What's the location of the wattage? 118. How do you determine conductor size? 119. Who has smaller AWG numb...
Read more