HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
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. 

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
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.

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.



Partner Zone
Latest Analysis
A small team of engineers has created a tackling dummy robot that's comparable to training with human players on the football field.
Several plastics and elastomers have come out recently for different parts of cars, as well as for multi-material medical devices and for onboard base station antenna components.
Work in embedding conductive materials into commercially available yarn could lead to energy textiles that store power for use.
A ball bearing developed for turbofan engines by FAG Aerospace of Germany and MTU Aero Engines could have other uses such as turbines, pumps, and gearbox stages.
Fifty-six-year-old Pasquale Russo has been doing metalwork for more than 30 years in a tiny southern Italy village. Many craftsmen like him brought with them fabrication skills when they came from the Old World to America.
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
9/10/2015 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.
Next Course August 25-27:
Sponsored by MICROMO
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