chinese speed controller for single phase AC motor - Page 1
Forum section: electronics / projects

author: Milan
author_rank: Contributor
timestamp: December 22, 2013, 03:27:38 pm
content: Hello,I buy some Chinese motors and speed controls units.Motors are OK, speed control unit work fine but all part inside are on main voltage (speed control potentiometer, tachogenerator wires ....)I plan to make new control units for this motors.Can you suggest me some ideas, IC or......

author: Asim
author_rank: Regular Contributor
timestamp: December 22, 2013, 04:39:39 pm
content: if you want an easy way to control a single phase AC motor, i would suggest triac.My graduation project was about speed control of an AC motor digitally.

author: Zero999
author_rank: Super Contributor
timestamp: December 22, 2013, 06:14:35 pm
content: What load is the motor drivingA TRIAC will work but the torque at low speeds will be reduced which is fine for something which requires less torque at lower speeds such as a fan but no good in an application needing high torque at low speed.

author: Milan
author_rank: Contributor
timestamp: December 22, 2013, 11:24:49 pm
content: @Asmin, @Hero999Thanks for replayApplication is honey extractor. On picture below you can see typical Chinese solutions.But I wont to make better and safer product.During honey extractions load is changing, I have to keep constant speed.Chinese speed control unit doing job done correctly but it is not safe.

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2013, 05:14:04 am
content: What is wrong with the Chinese controller, having it all at mains is not really a problem so long as the insulation for the parts is adequate and the clearance limits are obeyed, along with making sure all parts are bonded to the mains earth. Plenty of those out there with no problems.

author: oldway
author_rank: Super Contributor
timestamp: December 23, 2013, 07:51:53 am
content: Easiest solution is to use a main isolation transformer 1/1 of the same power as the power of the ac motor.

author: Milan
author_rank: Contributor
timestamp: December 23, 2013, 08:53:23 am
content: Quote from: SeanB on December 23, 2013, 05:14:04 amWe planning to get some safety certificate, so Chinese variant is not good enough.Quote from: oldway on December 23, 2013, 07:51:53 amMotors are 90W and 140W, isolation transformer will be too big and too heavy. I thank also that owner of company will not be heapy.

author: oldway
author_rank: Super Contributor
timestamp: December 23, 2013, 12:24:08 pm
content: QuoteModify the Chinese variant so it will fulfill IEC 60950-1 Norm, class2.There are 2 problems: the potentiometer and the backside connector.Enclosure is plastic, that's ok.Connector: remove it and tap the holes.Potentiometer: remove it too and tap the hole with a plastic plug.Use a remote plastic enclosure for the potentiometer.Choose a potentiometer with plastic shaft and mount it on a isolating board at 1cm from the plastic enclosure. It will pass all tests of class 2 isolation.

author: Milan
author_rank: Contributor
timestamp: December 23, 2013, 01:24:28 pm
content: Thanks for reply.In my first post attached file "chinese speed controller" is schematic of controller.It may be interesting for someone.Milan

author: oldway
author_rank: Super Contributor
timestamp: December 23, 2013, 02:20:15 pm
content: QuoteThat is an industrial project.I do not believe that the purpose of this forum is to provide free industries projects.

author: Zero999
author_rank: Super Contributor
timestamp: December 24, 2013, 03:57:08 pm
content: Yes, you should be able to modify the Chinese controller to make it safe. Without analysing it in great detail, it appears to be a simple phase controller with feedback to keep the speed constant. A better enclosure may be a good idea.Quote from: oldway on December 23, 2013, 02:20:15 pmI didn't know that. Where's the rule saying people can't ask for help with industrial projects?

author: calexanian
author_rank: Super Contributor
timestamp: December 24, 2013, 06:20:28 pm
content: Just to to oriental motor company and give them the requirements and have them make a suggestion, or go dc gear motor and controller. You need a ready made solution to meet UL requirements because listing of a new motor/driver can cost over 100k really fast!

author: Milan
author_rank: Contributor
timestamp: December 24, 2013, 06:57:41 pm
content: All this Chinese motors and speed controllers are very similar (almost identical) with panasonic product.I need to have ability to control motor speed from PIC (PWM + RC) so I need to change this schematic anyway.Milan

author: calexanian
author_rank: Super Contributor
timestamp: December 24, 2013, 07:37:47 pm
content: Well, still to this day the best thing the Chinese can really do is figure out ways to make something cheaper and not really design their own things. When they do you get travesties like this..http://www.thewirelesscatalog.com/wireless/Garden_3IA/View-all-Garden_3IB/Item_s-LIGHT-UP-RAINBOW-SPRINKLER_VM7512.html

author: SeanB
author_rank: Super Contributor
timestamp: December 24, 2013, 07:46:16 pm
content: Just proves there is a market for them, and an enterprising group made a gamble and started to supply this niche market.You get pretty good stuff in China, it may be rough and ready, but it works, especially the manufacturing machinery they make. They even have clones of them that work better and have interchangeable parts that are better quality than the original.

author: Rick Law
author_rank: Super Contributor
timestamp: December 24, 2013, 08:59:16 pm
content: Quote from: calexanian on December 24, 2013, 07:37:47 pmIn the not too distant future, we in the USA and the "west" will be in more direct competition with the Chinese - not in manufacturing alone but in high-end "brain" stuff. The worst one can do is to underestimate one's adversary.- We in the USA now is not even top 30 in the OECD PISA math & reading scores. The Netherlands and Germany are occasional top-five's. We have not seen ourselves anywhere near the top 5 in the last decade and longer. These days, China (Shanghai), China (Hong Kong SAR) trade back and forth being number one and number two.If you think we are so much better than they are and having nothing to worry about, I think you are not very well informed. As many would put in their article or TV show, for the past 1000 years, China has the world's highest standard of living for 900 of them.We damn well show them the respect they deserve as we fight hard to compete with them. Under estimate one's adversary is the short route to defeat.

author: calexanian
author_rank: Super Contributor
timestamp: December 24, 2013, 09:53:19 pm
content: I mean no insult to the future owners of this broke country. But they really have little innovation over there. Still so concerned with cheap cheap cheap. They have a long way to go to realize that you can't survive very long with that business plan because there is always somebody else willing to do it for less. Show me some products completely designed and originated in main land china in the last 25 years that did not start out as an idea from the outside. And I don't mean a smaller cheaper version of something that already existed.

author: Rick Law
author_rank: Super Contributor
timestamp: December 24, 2013, 10:45:05 pm
content: Quote from: calexanian on December 24, 2013, 09:53:19 pmWell, we in America should be the last to call them broke.I don't see any insults. I don't think you insulted them at all. However, you seem not to be aware that many historians consider that "in the last 1000 years, China had the highest standard of living for 900 of them."Sure, the 100 of which China was behind was the most recent 100. None the less, we cannot dismiss them as serious competition just because they failed to industrialize and felt behind. Particularly, a country with a long history of innovation and leadership in technology as they were.I am sincerely worry for ourselves. We have been living on our laurels - on the reputation and advancements we built in the past as the youths of other nations passed us by.This is what I wrote a couple of months back in another tread. The numbers are still current. (2012-2013 school year). Given how they are preparing the kids for their future, I would think we have a hard fight in this competition if we are to win:Quote from: Rick Law on June 02, 2013, 09:00:12 pmhttps://www.eevblog.com/forum/chat/what-languages-should-engineers-learn/60/

author: calexanian
author_rank: Super Contributor
timestamp: December 24, 2013, 11:08:37 pm
content: The most successful innovative people i know did not even complete, or even go to college, and those that did had majors in fields other than what they became successful in.

author: calexanian
author_rank: Super Contributor
timestamp: December 24, 2013, 11:41:49 pm
content: Ok, I gotta apologize for myself. I wont go back and change my post like to dork though. That was a very harsh thing to say. Yes, I am the first to admit this country has a real problem with the lack of education and declining standard of living. I do not coun't a big screen TV in every home to be a high standard. I mena things like debt and social problems. Erosion of family and loss of direction and a general apathy towards life. I blame it on not have star trek on the air anymoreThank God for the Maker movement and the fact that geek is kinda back in style a little bit. However China does have some problems. They are going through their growing pains and many of the men in control of businesses over there have less that just goals or business practices, just as we have had here and in europe over the last few centuries. We have the attitude now of what can we get from somebody else rather than what can I do for myself.

author: mianchen
author_rank: Regular Contributor
timestamp: December 25, 2013, 10:32:28 am
content: Quote from: calexanian on December 24, 2013, 11:41:49 pmEvery country has it's own problems. When looking at China, you cannot use western "standards" to evaluate it. It's run by a tightly controlled central "engine" that's capable of pursuing long term goals and realizing big projects. Most people only see the "cheap" manufacturing side of things and jump to conclusions. Because that's all they know about China.sent from Mars

author: oldway
author_rank: Super Contributor
timestamp: December 25, 2013, 10:34:19 am
content: Quote from: Hero999 on December 24, 2013, 03:57:08 pmEasiest way to solve this problem is to use an isolation 1/1 main transformer.A 150 VA isolation transformer is not "too expansive" if it's a project for one or two units.If you look at the schematic, you'll see that there is 0-5V DC input for speed setup.Speed can thus be controlled by an external 0-5Vdc voltage.Nothing has to be modify.It seems to be a mass production, and not one or two units.But "the owner of company will not be heapy"...he seems to be happy only with free projectsI like to help people who need it really but not owners of company. If they want some help, they are rich enough to pay for it.

author: Milan
author_rank: Contributor
timestamp: December 25, 2013, 11:14:51 am
content: @ oldwayIf you look at the schematic, you'll see that there is 0-5V DC input for speed setup.It is my modified schematic. Original schematic are in my first post.But "the owner of company will not be heapy"...he seems to be happy only with free projectsThis is always true.It seems to be a mass production, and not one or two units.No, plan is about 250 per year.The average monthly salary for someone who deals with the electronic or programming here is about 500 EUR (~700USD)From this you can pull conclusions.Maybe there was a misunderstanding.I work (my second job) for a company that uses these motors.I did not so lucky to have my own company.

author: oldway
author_rank: Super Contributor
timestamp: December 25, 2013, 12:28:22 pm
content: QuoteAnd you will work for peanuts ?This is not always thrue...Quote250 isolation mains transformers /year seems not to be a problem.QuoteThis is a good reason for not to do it free...You have to react or you will became a slave.

author: Milan
author_rank: Contributor
timestamp: December 25, 2013, 12:41:40 pm
content: hehehQuoteNo, but one job is not good enough to live here.QuoteIt is big problem, from company owner perspective. (only $$ is important to him)QuoteOf course I do not work for free.Milan

author: oldway
author_rank: Super Contributor
timestamp: December 25, 2013, 01:45:15 pm
content: QuoteWhy would we help for free you to do the job you are paid for ?

author: Zero999
author_rank: Super Contributor
timestamp: December 25, 2013, 01:56:28 pm
content: I've no problem with helping someone with a job they're being paid for, even though I don't receive any money myself.I think it will be much cheaper to use an isolation transformer, by the time labour and materials have been taken into account.

author: Milan
author_rank: Contributor
timestamp: December 25, 2013, 01:57:25 pm
content: Because I don't care when someone ask me for this kind of help.I posted schematic of original control unit here and when I finish this I will post my final solutions.

author: oldway
author_rank: Super Contributor
timestamp: December 25, 2013, 02:30:00 pm
content: Quote from: Hero999 on December 25, 2013, 01:56:28 pmI agree, it seems to be the smartest solution.We tried to help for free, but "that is not enough"...