HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Feature
Automation & Motion Control

Factory Automation Design & the AC-DC Equation

NO RATINGS
Page 1 / 2 Next >
View Comments: Oldest First|Newest First|Threaded View
Rob Spiegel
User Rank
Blogger
AC or DC?
Rob Spiegel   12/5/2013 10:53:12 AM
NO RATINGS
Good article, David. You showed just how complex this question actually is.

William K.
User Rank
Platinum
The decision between motor types
William K.   12/6/2013 8:57:24 PM
NO RATINGS
This is an interesting post that does provide some useful insight. But the slant toward brushless low voltage motor controls is sort of obvious. So clearly the choice needs to be based at least partly on just exactly what the motor need to do. But other concerns include the cost of controls and the maintenance of those controls. A standard small three-phase motor can go for many years with no attention at all, and if something does eventually fail there are lots of folks qualified to do the repairs. Brushless motors are quite a bit more complex, and servicing their systems requires a good bit more skill and education.

So the choice is not always simple and straight-forward.

Cabe Atwell
User Rank
Blogger
Re: The decision between motor types
Cabe Atwell   1/20/2014 5:36:50 PM
NO RATINGS
Indeed, some factories require both AC and DC, which can further complicate matters.

William K.
User Rank
Platinum
Re: The decision between motor types
William K.   1/20/2014 8:54:22 PM
NO RATINGS
We have an interesting statement here, "AC motors must generate a magnetic field in order to operate. As a result, AC motors typically have high inrush currents." My experience is that ALL motors must generate a magnetic field to operate. Sort of an interesting argument. PM motors don't need to generate two magnetic fields, so they are a bit more efficient in that aspect. 

What is indeed certainis that some kinds of motors are easier to control than others, and some are much simpler to ramp up the speed with than others. But just running on a lower voltage actually reduces efficiency because the resistance losses are greater. The 24 volt DC motor is probably a lot simpler to use as an intermittant duty motor with the speed ramped up and down, and it is undoubtedly more efficient than an AC motor running constantly with a slip clutch slipping when things are halted. 

My point here is that the benefits come from the application of more complex control schemes, not because of some particular technology. Variable speed AC drives can also deliver some real savings. 

Partner Zone
Latest Analysis
A South African startup is combining recycled plastic with solar power to give underprivileged school children a stylish schoolbag that also supplies them with light to study by.
An in-depth survey of 700 current and future users of 3D printing holds few surprises, but results emphasize some major trends already in progress. Two standouts are the big growth in end-use parts and metal additive manufacturing (AM) most respondents expect.
Technology and global expansion are playing key roles in making manufacturing an attractive field for women to join, more than ever before, said the president of a woman-owned family of companies.
A few years ago, reshoring roared onto the scene as the next great movement in manufacturing, but the data so far reflect otherwise.
In another sign that self-driving cars are on the distant horizon, Ford has been granted a patent for an “autonomous vehicle with reconfigurable seats.”
More:Blogs|News
Design News Webinar Series
8/13/2015 11:00 a.m. California / 2:00 p.m. New York
6/25/2015 11:00 a.m. California / 2:00 p.m. New York
6/24/2015 11:00 a.m. California / 2:00 p.m. New York
6/11/2015 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Aug 31 - Sep4, Embedded System Design Techniques™ - Writing Portable and Robust Firmware in C
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service