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## An example of calculating transformer size and voltage drop due to starting of large motor

Limited Time Offer: Save 15% on Pro Plan with discount coupon: MX15. Study specialized LV/MV/HV technical articles and studies.

Electric Motor

# Motor Starting via Chokes or Resistors

The series-connected chokes (Figure 1) or resistors (Figure 2) reduce the voltage at the motor and hence also the starting current. The starting torque is reduced by around the square… Read more

Mar 07, 2014 | By Edvard Csanyi

Electric Motor

# Inspection and test procedures for Rotating Machinery, Synchronous Motors and Generators

Visual and Mechanical Inspection Electrical Tests Test Values Visual and Mechanical Tests Electrical Tests Pictures: Electrical machine wired for electrical testing The Electrical Machines Laboratory TABLE 100.10 – Maximum Allowable… Read more

Feb 19, 2014 | By Edvard Csanyi

Electric Motor

# Calculating the short-circuit current across the terminals of a synchronous generator

Calculating the short-circuit current across the terminals of a synchronous generator is very complicated because the internal impedance of the latter varies according to time. When the power gradually increases, the… Read more

Jan 13, 2014 | By Edvard Csanyi

Electric Motor

# Heat as one of the most common cause of motor failure

Heat is the most common cause of motor failure before reaching rated service life. Every increase of 10 degrees Centigrade of a motor’s windings above its design operating temperature cuts… Read more

Nov 22, 2013 | By Edvard Csanyi

Electric Motor

# Identity Card of Every Asynchronous Motor

A motor is characterized by different electrical and constructional parameters which identify its correct application field. The whole of all these parameters constitutes the rating of the machine and is… Read more

Nov 18, 2013 | By Edvard Csanyi

Electric Motor

A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments when electrical… Read more

Nov 06, 2013 | By Edvard Csanyi

Electric Motor

# 4 motor designs identified in NEMA MG1

Performance requirements for various types of induction motors for use on standard sinewave power supplies are identified in NEMA MG1. Some of these types of motors are suitable for use… Read more

Nov 01, 2013 | By Edvard Csanyi

Electric Motor

# Testing and commissioning procedure for electric motors

It should be noted that the scope of motor testing depends upon the motor type and size, this being indicated on the inspection forms. Motor vibration shall be measured in… Read more

Sep 20, 2013 | By Edvard Csanyi

Electric Motor

# Sizing The DOL Motor Starter Parts (Contactor, Fuse, Circuit Breaker and Thermal Overload Relay)

Calculate size of each part of DOL motor starter for the system voltage 415V, 5HP three phase house hold application induction motor, code A, motor efficiency 80%, motor RPM 750,… Read more

Sep 11, 2013 | By jiguparmar

Electric Motor

Good Evening all, in this session I’m going to present some of the issues in drive design in the field of Electric Vehicle. I’ve organized the whole series into modules… Read more

Aug 21, 2013 | By Vishy

Electric Motor

# 7 Most Common Motor Enclosure Types Defined By NEMA Standards

The enclosure of the motor must protect the windings, bearings, and other mechanical parts from moisture, chemicals, mechanical damage and abrasion from grit. NEMA standards MG1-1.25 through 1.27 define more… Read more

Aug 09, 2013 | By Edvard Csanyi

Electric Motor

# Motor Service Factor (SF) Defined By NEMA

Motor Service Factor (SF) is the percentage of overloading the motor can handle for short periods when operating normally within the correct voltage tolerances. This is practical as it gives… Read more

Aug 07, 2013 | By Edvard Csanyi

Electric Motor

# NEMA Definition Of Motor Full Load Nominal Efficency (Standard MG1-12.54.2)

Efficiency is defined as the ratio of the power output divided by the power input. Machine losses are in the form of heat, and include: Stator winding loss, Rotor loss,… Read more

Aug 02, 2013 | By Edvard Csanyi

Electric Motor

# Selection Of Crane Duty Motors (Part 3)

Continued from second part: Selection Of Crane Duty Motors (Part 2) N = Duration of motor operation under rated conditions R = Duration of motor at rest and de-energised ØMax… Read more

Jul 27, 2013 | By Ashok Parikh

Electric Motor

# Selection Of Crane Duty Motors (Part 2)

Continued from first part: Selection Of Crane Duty Motors (Part 1) Following two types of motors are widely used for crane duty applications. Squirrel Cage Crane Duty Motors Slip ring… Read more

Jul 24, 2013 | By Ashok Parikh