Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

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Electrical units, amps and electrical wiring, wire gauge and AWG, electrical formulas and motors

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12 Volt Current and Maximum Wire Length

Maximum copper wire length with 2% voltage drop

Abbreviations According the International Electrotechnical Commission

Conforming abbreviations according IEC

AC - Active, Reactive and Apparent Power

Real, imaginary and apparent power consumption in AC circuits

AC Circuit - Voltage, Current and Power

In an AC circuit - alternating current is generated from a sinusoidal voltage source

Aluminum Conductor Characteristics

Characteristics of all-aluminum conductor (AAC)

Amps and Wire Gauge in 12V Electrical Circuits

Maximum current - amps - through a 12V circuit - related to size (AWG) and length of wire

Asynchronous Induction Motors - Electrical Data

Electrical motor data - nominal current, fuse, start ampere, contactor and circuit breaker of asynchronous induction motors

Automotive 12 Volt Electric Wiring

Car - 12 V currents and maximum wire lengths

AWG - American Wire Gauge and Circular Mils

AWG, diameter mil, circular mil, diameter in mm and area in mm2

AWG vs. Square mm - Wire Gauge Converter

American Wire Gauge (AWG) vs. cross sectional area in square mm.

AWG Wire Gauges Current Ratings

Common US AWG wire gauges and amps ratings


Capacitors and capacitance - charge and unit of charge

CE Marking

The European Machine Directive

Charging Electrical Vehicles - Voltage, Amps and Power

EV - Electrical Vehicle - Charging Stations - Power vs. Amps and Voltage - AC vs. DS - Single Phase vs. Three Phase

Circles within a Rectangle

The maximum number of circles possible within a rectangle - ex. numbers of pipes or wires in a conduit

Circuit Wiring - Single Phase 230V Electrical Motors

Recommended copper wire gage and transformer size for single phase - 230 Volts - electrical motors

CM - Circular Mil Area

The circular mil area - CM - is a unit denoting the cross-sectional size of a wire or a cable

Color Temperatures

Light sources and color irradiation

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Copper and Aluminum Wire - Electrical Resistance

Electrical resistance in plain copper or aluminum wire

Copper Wire - Electrical Resistance

Gauge, weight, circular mils and electrical resistance

Coulomb's Law

The electric force acting on a point charge

Current Divider - Online Calculator

Electric current divider

DC Motors - Full-load Currents

Full load amps in 120 and 240 volts DC motors

Dielectric Strength of Insulating Materials

Ability to act as an electrical insulator

DIN VDE Standards

DIN VDE power installations

Electric Cable Installations - Current Rating

Current ratings and cable sizes for fixed installations within buildings

Electric Circuit Diagram - Drawing Template

Online shareable electric circuit diagram.

Electric Heating of Mass

Electric heating of an object or mass - energy supply and temperature change

Electric Motor Calculator

Calculate amps, hp and kVA

Electric Motor Efficiency

Calculate electric motor efficiency

Electric Motor Wiring - 480 Volt

Electrical motor wiring data - NEMA amps, starter size, HMCP size for motors ranging 1/2 to 500 hp

Electric Motor Wiring - Three Phase 230 & 460V Circuits

Recommended dimensions of copper wire and transformers for tree phase 230 & 460V electrical motors

Electric Motors - Torque vs. Power and rpm

Speed of electrical motors - output power and torque

Electric Shocks

Physiological effects of electric shocks

Electric Wire 240 Volts Single-Phase - Maximum Length

Maximum length of wire with 2% voltage drop

Electric Wire Cross-Section Equations

Calculate single and bunched wire cross-sections and diameters

Electric Wire Resistance Various Materials

Copper, Aluminum, Brass, Constantan, Nichrome, Platinum, Silver and Tungsten

Electrical Conductivity of Elements and other Materials

Elements ability to conduct electric current

Electrical Formulas

The most common used electrical formulas - Ohms Law and combinations

Electrical Inductance - Serial and Parallel Connections

Serial and parallel inductance

Electrical Induction Motors - Synchronous Speed

The speed at which an induction motor operates depends on the input power frequency and the number of electrical magnetic poles in the motor

Electrical Metal Tubing - EMT - Conduits

Electrical Metal Tubing (EMT) conduits trade sizes and max distance between supports

Electrical Motor - Locked Rotor Design Code Letters

Locked rotor indicating code letters electrical motors

Electrical Motor Power and Maximum Cable Length

Maximum cable lengths for electrical motors

Electrical Motor Shaft Power

Electrical motors are rated in horsepower or watt

Electrical Motors - Frame Dimensions

NEMA electrical motor frame dimensions

Electrical Motors - Full Load Amps

Full load currents for 460 volts, 230 volts and 115 volts motors - single and 3-phase

Electrical Motors - Horsepower and Amps

Horsepower rating of electrical motors compared to their ampere rating

Electrical Motors - Insulation Classes

Temperature and insulation classes for electrical motors

Electrical Motors - Speed vs. Frequency

The speed of electrical motors with 2, 4, 6 or 8 poles at 50 Hz and 60 Hz

Electrical Motors Efficiency Ratings

NEMA - electrical motor efficiency ratings

Electrical Motors Speed at Operating Loads

Speed of an operating electrical motor with load is lower than the synchronous speed (no load) of the motor

Electrical Resistance in Serial and Parallel Networks

Resistors in parallel and serial connections

Electrical Units

Definition of common electrical units - like Ampere, Volt, Ohm, Siemens

Electrode Potential and Galvanic Corrosion

Introduction to electro chemical series and corrosion of metals

Electromotive Force - e.m.f

Change in electrical potential between two points

Energy Stored in Capacitors

Potential power and energy stored in capacitors

Energy Stored in Inductors

Energy stored in magnetic fields

Extension Cords

Size of extension cords - full load ratings with 115 V

Heat Loss from Electrical Motors

Heat loss from electrical motors to the surroundings

IEC - NEMA Electric Motors Standard Torques

IEC and NEMA torque classifications of electrical motors

IEC Duty Cycles

The eight - S1 - S8 - IEC duty cycles of operating electrical motors


Electro Magnetic Field - EMF - induced into a circuit

Induction Motors - Synchronous and Full Load Speed

Synchronous and full load speed of amplitude current (AC) induction motors

Intermediate Metal Conduit - IMC

Lighter and lower cost metal conduits

IP - Ingress Protection Rating

IP - Ingress Protection rating is used to specify the environmental protection - or electrical enclosure - of electrical equipment

Kirchhoff's Laws

Kirchhoff's current and voltage laws

LENI - Lighting Energy Numeric Indicator

Energy consumption of lighting systems

Lights and Power Installations

Lights power installations in common types of buildings and rooms

Luminous Efficacy

The visible light produced by light sources

Max Amps in Copper and Aluminum Wire

Maximum current in copper and aluminum wire

NEMA - National Electrical Manufacturers Association

National Electrical Manufacturers Association

NEMA A, B, C and D Electrical Motor Design

NEMA has established four different designs - A, B, C and D for electrical induction motors

NEMA and IEC Enclosure Classifications

NEMA enclosure classifications versus IEC enclosure classifications

NEMA Enclosure Standards for Electric Motors

NEMA enclosure standard for electrical motors

NEMA Insulation Classes

Electrical insulation systems rated by standard NEMA classifications to maximize allowable operating temperatures

Nema Starters

Nema sized contactors or starters

Nickel-Chromium Wire - Electrical Resistance vs. Temperature Rise

Electric resistance and temperature rise

Ohm's Law

Voltage, current and resistance

Online Wire Gauge - AWG - Calculator

Calculate AWG, mil, mm, CM or square mm

Parallel and Serial Connected Capacitors

Capacitance in parallel and series connected circuits

Parallel Circuits

Resistance, voltage and current in parallel networks


Electromagnetism and formation of magnetic fields

Potential Divider - Online Calculator

Output voltage from a potential divider

Power Factor - Inductive Load

Inductive loads and power factors for electrical three-phase motors

Power Wiring - Color Codes

Color codes used in power wiring

Rechargeable Batteries - Battery Life Calculator

Properties of rechargeable batteries and accumulators

Relative Permittivity - the Dielectric Constant

Some common materials and their relative permittivity

Relative vs. Absolute Voltage

Electric circuits and the voltage at any point

Resistance and Conductance

The reciprocal of electrical resistance is conductance

Resistance and Resistivity

Electrical resistance and resistivity

Resistivity and Conductivity - Temperature Coefficients for Common Materials

Resistivity, conductivity and temperature coefficients for some common materials as silver, gold, platinum, iron and more

Resistors - Color Codes Calculator

Color codes for fixed resistors - values and tolerances - online calculator

Resistors - Letters and Digit Codes

Letter and digit codes to indicating resistor values

Resistors - Standard Values

Preferred number series for resistors

Rigid Aluminum Conduit - RAC

Rigid Aluminum Conduit dimensions

Series Circuits

Voltage and current in series circuits

Service Factor

Service factor - SF - is a measure of periodically overload capacity at which a motor can operate without damaging

Single Phase Power Equations

Single phase electrical power equations

Single vs. Three Phase AC - Amperage

Convert between single phase (120, 240 and 480 Voltage) and three phase (240 and 480 Voltage)

Slip in Electrical Induction Motors

Slip is the differentiation between synchronous and asynchronous speed

Smaller Circles within a Larger Circle

Estimate the number of small circles that fits into an outer larger circle - ex. how many pipes or wires fits in a larger pipe or conduit

Soil - Resistivity

Types of soil and their mean value of resistivities

SWG - Standard Wire Gauge

Imperial Standard Wire Gauge used for sheet metal and wire

Three Phase Electrical Motors

Full load amps, wire and conduit sizes for three phase electrical motors

Three-Phase Power Equations

Electrical 3-phase equations

Torques in Electrical Induction Motors

Torques describes and classifies electrical motors


Alternating voltage and induced electro magnetic field - e.m.f. - in a transformer


A transient is a high voltage spike caused by an external or internal transient source

Types of NEMA Electrical Enclosures

Description of NEMA electrical enclosures types

Voltage by Country

Typical voltages and frequencies used for domestic appliances

Voltage Drop in Electric Circuits

Ohm's law and voltage drop in an electric circuit

Voltage Imbalance - Derating Factor in Polyphase Motors

Efficiency of electrical polyphase motors decreases with increased voltage imbalance

Wire - Convert from Square mm to Diameter mm

Convert from square mm to diameter mm


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