EC&M®

advanced search

About Us
Contact Us
Subscribe
Advertise
Login
Classifieds

power quality
design / engineering
ops & maintenance
market trends
product depot
lighting
voice / data / video
construction
grounding
NEC
training
- Electrical Basics

Evaluating Motor and Transformer Inrush Currents

Published Friday, December 01, 2006

Inrush currents associated with motor starting and transformer energizing can cause interaction problems with other loads in a facility or on the power system, particularly sags that trip loads. Protection devices can misinterpret these events as fault currents, if the devices are not properly coordinated. Coupled with the tendency of other constant power devices to increase current to make up for the reduced voltage, the inrush current may cause protection devices to trip. Energizing a transformer has the additional issue of harmonics in the inrush current, which can excite system resonances and cause dynamic overvoltages. <b>Fig.</span>
<h3>To continue reading this article, please register or login – it’s quick and free…</h3>
</div>
<div id=

<b>Fig.</span>
<h3>To continue reading this article, please register or login – it’s quick and free…</h3>
</div>
<div id=

Member Login

Email Address:

Password:

Remember me

Forgot password? Need Help?

Enter your email address below, and we'll email your password.

Email:

Are cookies enabled in your browser?

This site uses cookies and session data to keep track of your name and preferences while you're logged in. You cannot login without enabling cookies.

One Step Registration

Fill out the form below for instant access to the page you’ve requested.

Website members also receive access to our entire archive and may apply for a complimentary subscription to our print magazine.

All fields are required Personal Info

Email Address Required Must be a valid email

Password Required Passwords must match

Confirm Password Required

First Name Required

Last Name Required

Company Name Required

Job Title Required

Zip/Postal Code Required

Country Required

Electrical Construction & Maintenance Magazine

Yes! I wish to receive Electrical Construction & Maintenance Magazine for FREE
* Free to qualified subscribers only.
No thanks

Address Required

City Required

State/Province Required

Business Phone Required

How would you like to receive your copy of EC&M? (Check only one. If you want to receive the digital version of the magazine, we must have your email address) Print
Digital Required

Which ONE of these best describes your organization’s primary business activity? Electrical contracting
Low-voltage/communications contracting
Manufacturing; processing; warehousing
Oil & gas; mining
Commercial (office complex, hotel, data processing, financial, communications, recreational, retail).
Healthcare
Institutional (educational, religious, correctional)
Transportation services (air, rail, marine, motor)
Utility (electric, gas, water, sanitary)
Engineering; consulting; A/E; design-construct; architectural; general contracting
ESC(Energy Service Company)
OTHER (please specify) Other: Required

Which ONE of these best describes your primary job title? Owner; partner; president; v.p.; general manager
Plant electrical engineer; chief electrical engineer; plant engineer; chief engineer; maintenance engineer; facilities manager; energy manager
Project manager; job superintendent; general foreman; job foreman; supervisor; electrical foreman; maintenance supervisor
Electrical engineer; consulting electrical engineer; staff engineer; designer; architectengineer; project
Electrician; electrical technician; electrical journeyman; maintenance technician
Estimator
Purchaser
Inspector
Other (please specify) Other: Required

How many people are in your entire company or organization (in all locations)? 500+
250-499
100-249
50-99
20-49
10-19
5-9
1-4 Required

What is the month of your birth?*
*In lieu of a signature, we require a unique identifier used for subscription verification purposes by our auditing bureau. January
February
March
April
May
June
July
August
September
October
November
December Required

Remember me

Submit the form for instant access to the page you've requested.

in this issue

Commercial Breakdown
A/C and Refrigeration Systems
Nursing Home Power Needs

Subscribe to Digital Edition

what's wrong here?

What's Wrong Here?

Oct 22, 2009 11:16 PM

What's Wrong Here?

Oct 8, 2009 3:32 PM

What's Wrong Here?

Sep 24, 2009 1:13 PM

View all What's Wrong Here?

What's Wrong Here
Sponsored By:

product of the week

Fire alarm system

October 26, 2009

View all 2009 Products of the Week

Shocking Stats

2.3% More Industry Statistics

Recent Comments

More...

Exterior Fixture Box for Brick or Stone

Installing a fixture box in a brick or stone wall just got easier with Arlington�s new adjustable depth box!

Southwire's 2009 Cable Innovation Road Show

Gain years worth of insight in only 2-1/2 hours with Southwire�s 2009 Cable Innovation Road Show with Grounding Seminar. The agenda is packed with valuable information that focuses on installation tips!

More...

Sizing Gen-Sets: Facts, Hints, and Good Judgment

The complexities of today�s commercial or industrial facility, with their equipment environment of linear and nonlinear loads, places a whole new light on sizing engine-generator sets.

More...

Arc Mitigation - A Total System Approach
There�s no question the risk of arc flash hazards is real in the electrical industry. What many don�t always realize is the impact in business interruption from such events typically far outweighs the physical damage to equipment. View this On Demand Webinar!

Implementing an Industrial Ethernet Infrastructure that's Built to Last
This webinar explores the key benefits of implementing a robust complete, end-to-end Industrial Ethernet solution � from cabling and connectivity, to active components and associated hardware. View this On Demand Webinar!

More...