Dc Motor and Drives Training

Does anyone happen to have any good links for learning dc motors and dc drives.

I have no experience with dc drive and motor systems and no money for some of the videos from coastal and such.

I have been looking but can't find anything free that is very helpful.

Any suggestions?

Look at Baldor and Reliance web sites. Fairly good for motor theory and some on DC drives.

Local library. Here in Wa King County Library has a fantastic inter library loan program. Get me books from all over. Got me one from Australia. No charge. They budget for $700 per cardholder yearly for this service.

Maybe you can get high school let you attend junior college or even a university (too much calculus at this stage I think) and get dual high school and college credit.

With you going to school and working when are you going to have the time to study?

Dan Bentler

try the online webcast of microchip.com they have webcast about DC motor basics and theory.

hope it can help.

Den Mark

Try this

http://www.sea.siemens.com/step/default.html

Hi PLC Kid:
This is not exactly for DC drives and DC motors but for motors in general.
http://www.baldor.com/pdf/manuals/PR2525.pdf

Dan

I am currently taking 2 college classes and 1 class at my technical school for senior year high school credit.

As far as studying I get some done at work when things are slow (my boss is trying to help me) and on weekends I pack a lot in when not working on Saturday.

Graduation in 5 more weeks and then I am going start looking at what I can do on college courses.

I did find a few good things on a couple different areas of automation at the local library and have got the info to setup on the loan program. Thanks for that info I never knew they did that. I just have never used our public library that much as I do the high school and college library. There are some good books at the tech school but I am trying to buy only what I need for my classes as I am cash strapped. My mother is on disability and so I kind of have to help buy stuff to keep the home up and all.

Been having to dump a lot of money into home repairs and such and I am also trying to learn that as I go just to save money.

It’s not easy but I am going into automation and I am going to get my engineering degree come h$*^ or high water.

Thanks for all the links and help guys I am going to try and go through a lot of this this weekend.

Sorry for taking so long to respond but it has been a real tough week.

im lost wit scape

i wrote a program 2 years ago for a line welder control 4 stepper motors and analog sensors. used automationdirect plc. got a another big project coming up my problem is and i have to go to horner ocs which runs cscape and i dont understand the program langush any pointers how to get over that hump

With all the irons in the fire and all you are doing I see no reason to apologize.

Any way I can help let me know.

Took a look at http://www.baldor.com/pdf/manuals/PR2525.pdf
It is a good general referance that is good to keep for future use when you have to look up "now what did I know about intertia and have forgot" Has some DC control in it but not all you need.

It is just my opinion BUY if you want to study something I would concentrate on VFDs. I theorize DC motors and controls in industry will mostly be a thing of the past in 10 or 15 years. As an example when has anyone seen an operating Ward Leonard drive? On other hand if the plant you are working in has lots of DC then it would definitely be worth your time.

IF Dick DV gets in here listen to him he is the motor and drive guru.

Dan Bentler

A while ago I was looking to brush up on drives and found that the Indian Institute of Technology has posted almost all of their lectures on Youtube.

There are 40 videos on Industrial Automation and Control-each video is about 1 hour.
http://www.youtube.com/view_play_list?p=E8F9BF5CB1201D23

This is for Industrial Drives, 37 videos.
http://www.youtube.com/view_play_list?p=ED1B6C0DE8A84B6E

These are actual college courses, I have only watched a couple but they seem to be pretty good if you already have a background.

Our plant is something like 70% dc drive systems and 3o% ac drive systems.

We have alot of older dc drives of various brands that are being changed to power flex dc drives.

I wish the applications could be changed to ac and some have but the vast majority need dc motors so say the oem.

I do not buy that fully. In some of our apps yes but many that are dc and are being converted to newer dc drives are apps that i have seen before using ac drives.

I do not currently know enough of the dynamics of either to make a good argument. I am pretty good at troubleshooting basic setup and programming of ac drives but the knowledge required to size and spec for a new or retofit system or to convert from ac to dc is what i am primarily seeking.

We have a rockwell ac/ dc motors and drives class here in atlanta in june and i will be attending that also.

I hear those are pretty good but still alot of info to pack into 4 days.

Thanks for the education guy's

The question of when and when NOT to switch to AC from DC is one to save for that class.

These are the guys to ask questions to.

Get lots of sleep buy a water cooled pen and take lots of notes. These classes are expensive so you may as well get best advantage of your employer dollar.

Dan Bentler

PLC Kid, I think your instincts are correct regarding conversion of DC systems to AC. After over 15 years in the field doing these conversions in a huge variety of applications, I can confortably say that the application where DC is the best choice based solely on performance is getting exceedingly rare. The choice to stay with DC is almost always a commercial (that would be cost) one. And, I mean initial cost, at that. Anyone doing life-cycle costing would choose AC with precious few exceptions.

Just a couple of key points:

All things being equal, AC is far less motor maintenance than DC. AC will, on average, get you 6% better energy efficiency. If your application would benefit from an enclosed vs. open motor, it is far easier and cheaper to build an enclosed AC motor. If you have to do high torque work at or near zero speed, AC is preferred today because of commutator damage under those conditions in DC, and finally, in hazard-rated atmospheres (explosion-proofing) DC is simply not a candidate due to brush arcing.

Now I'm sure someone out there will have some reason why DC is just right for their application and they might be right but, in general, the above reasons make DC a second choice technology and, in many cases, a distant second choice.

For me personally, while I work on DC regularly, I've never liked the inherent instability of DC motors. By that, I mean the fact that they will run away to overspeed on field failure or that they are not near-synchronous devices like induction motors. I've always disliked the need for a tach or encoder to get any kind of speed accuracy in DC, and, with compound-wound DC machines, the problems associated with directionality due to the polarity of the series field connections.

Maybe I'm just not old enough (at 63yo that's hard to believe!) to appreciate DC but, then, I really am not fond of analog drives whether AC or DC either!