Basic Motor Formulas And Calculations

The formulas and calculations which appear below should be used for estimating purposes only. It is the responsibility of the customer to specify the required motor Hp, Torque, and accelerating time for his application. The salesman may wish to check the customers specified values with the formulas in this section, however, if there is serious doubt concerning the customers application or if the customer requires guaranteed motor/application performance, the Product Department Customer Service group should be contacted.
Rules Of Thumb (Approximation) motor formulas motor formulas motor formulas motor formulas motor formulas
At 1800 rpm, a motor develops a 3 lb.ft. per hp
At 1200 rpm, a motor develops a 4.5 lb.ft. per hp
At 575 volts, a 3-phase motor draws 1 amp per hp
At 460 volts, a 3-phase motor draws 1.25 amp per hp
At 230 volts a 3-phase motor draws 2.5 amp per hp
At 230 volts, a single-phase motor draws 5 amp per hp
At 115 volts, a single-phase motor draws 10 amp per hp
Mechanical Formulas motor formulas motor formulas
Torque in lb.ft. = HP x 5250 rpm HP = Torque x rpm 5250 rpm = 120 x Frequency No. of Poles
Temperature Conversion
Deg C = (Deg F - 32) x 5/9
Deg F = (Deg C x 9/5) + 32
High Inertia Loads
t = WK2 x rpm 308 x T av. WK2 = inertia in lb.ft.2t = accelerating time in sec.T = Av. accelerating torque lb.ft..
T = WK2 x rpm 308 x t
inertia reflected to motor = Load Inertia Load rpm Motor rpm 2
Synchronous Speed, Frequency And Number Of Poles Of AC Motors
ns = 120 x f P f = P x ns 120 P = 120 x f ns
Relation Between Horsepower, Torque, And Speed
HP = T x n 5250 T = 5250 HP n n = 5250 HP T
Motor Slip
% Slip = ns - n ns x 100

Code KVA/HP Code KVA/HP Code KVA/HP Code KVA/HP
A 0-3.14 F 5.0 -5.59 L 9.0-9.99 S 16.0-17.99
B 3.15-3.54 G 5.6 -6.29 M 10.0-11.19 T 18.0-19.99
C 3.55-3.99 H 6.3 -7.09 N 11.2-12.49 U 20.0-22.39
D 4.0 -4.49 I 7.1 -7.99 P 12.5-13.99 V 22.4 & Up
E 4.5 -4.99 K 8.0 -8.99 R 14.0-15.99
Symbols
I = current in amperes
E = voltage in volts
KW = power in kilowatts
KVA = apparent power in kilo-volt-amperes
HP = output power in horsepower
n = motor speed in revolutions per minute (RPM)
ns = synchronous speed in revolutions per minute (RPM)
P = number of poles
f = frequency in cycles per second (CPS)
T = torque in pound-feet
EFF = efficiency as a decimal

WORLD POWWWER

Electric power is defined as the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt.


Electrical power is distributed via cables and electricity pylons like these in Brisbane, Australia.When electric current flows in a circuit with resistance, it does work. Devices convert this work into many useful forms, such as heat (electric heaters), light (light bulbs), motion (electric motors) and sound (loudspeaker). Electricity can be produced by generation or from storage such as batteries.

ELECTRONIC CITY

Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information. Although considered to be a theoretical branch of physics, the design and construction of electronic circuits to solve practical problems is an essential technique in the fields of electronics engineering and computer engineering.

The study of new semiconductor devices and surrounding technology is sometimes considered a branch of physics. This article focuses on engineering aspects of electronics. Other important topics include electronic waste and occupational health impacts of semiconductor manufacturing.

FATHER OF ELECTRICITY

Early developments
Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.[2] However it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise on Electricity and Magnetism.[3]

ELECTRICAL ENGINEERING

DISCIPLINE OF A PERSON

DISCIPLINE OF A PERSON

To discipline thus means to instruct a person or animal to follow a particular code of conduct, or to adhere to a certain "order," or to adopt a particular pattern of behaviour. So for example, to discipline a child to wash its hands before meals. Here, 'washing hands before meals' is a particular pattern of behaviour, and the child is being disciplined to adopt that pattern. 'To disciple' also gives rise to the word disciplinarian, which denotes a person who enforces order. An ideal disciplinarian is one who can enforce order without coercion. Usually however, the phrase 'to discipline' carries a negative connotation. This is because enforcement of order - that is, ensuring instructions are carried out - is often regulated through punishment.


Self-disciple refers to the training that one gives one's self to accomplish a certain task or to adopt a particular pattern of behaviour, even though one would really rather be doing something else. Thus, self-discipline is the assertion of willpower over more base desires, and is usually understood to be a synonym of 'self control'. Self-discipline is to some extent a substitute for motivation, when one uses reason to determine a best course of action that opposes one's desires.