Yes but that's another bit you omitted, what else have you omitted in your low cost alternative? Start adding this up and you will soon see where you are.
-- Regards,
John Stevenson Nottingham, England.
No re-read it. He was terming your little episode as an inventor as cobbling up, then went onto giving an insight into EMC testing. An expensive episode you tended to miss, or perhaps Poundland don't do this??
-- Regards,
John Stevenson Nottingham, England.
Sorry old Bean, just been thru the same thing on some industrial machines. Have a word with BSI on what is needed BY LAW.
-- Regards,
John Stevenson Nottingham, England.
You clearly haven't actually tried driving a rotary table of the kind most hobbyists are likely to use. On the other hand, I have.
Regards, T>The use of stepper motors to drive a rotary table in
Utter nonsense. Unless, of course, my bench PSU is reading back to front on the current scale. Perhaps I'd better send it back to Magenta for repair...
Regards, T>You're not right there. the holding current is less
...so now you're changing the rules (as usual). You started this particular thread by stating:
"For those of us who like to "Roll our own", (isn't that all of us?) it would seem that the cost of manufacturing our own Quotient Mistress, using off-the-shelf professionally produced circuit boards, is about £36."
Now, having had it pointed out to you that this was total cr@p, you start talking about using a different chip. Where are the hobby board kits to support that? apart from in your imagination?
Regards, Tony
Go read the legislation. Clearly you haven't.
Regards, T>You're not right there.
So what are you suggesting? That the hobbyist goes out & buys the necessary test gear to do EMC testing at home? Give me a break.
Self-certification just isn't an option either for the hobbyist or the small manufacturer.
Regards, T>These days you self-certify to CE using your own test logs.
Pity. I would have enjoyed seeing you fail.
Regards, Tony
Don't be nasty Tony. Remember we as tax paying citizens are funding any work done by Harricot and the other 4 Beans. When I send my next cheque in for the very nice National Insurance people I shall put an exemption slip in with it so none of it goes to the NHS for Mr Beans medication because he's obviously not taking it.
-- Regards,
John Stevenson Nottingham, England.
Don't mislead. You yourself said that the current was controlled by your unit (and therefore is not indicative of the actual holding current required). If you were to conduct an experiment whereby you measured the current at which the retaining torque failed against the load, then you would, indeed, find that the holding current is less than the stepping current.
One really has to ask whether your contribution quoted below is a serious contribution to a discussion amongst hobbyists seeking to produce something by their own efforts?
It seems to be a somewhat childish rant to me.
"you're changing the rules (as usual)"? This is a thread exploring how we the hobbyists might do things for ouselves much cheaper than the "cynical" (your word) traders would charge us for the same thing. You yourself have contributed many articles over the years persuading the hobbyist to do just that.
"changing the rules (as usual)"? Not at all. In a design project carried on by the NG, we will get to our final design by discussion; a proposal is made, a discussion ensues, and a conclusion is reached. In this case, I saw the products advertised by Magenta and proposed them. You brought into play your experience of using them, and so the discussion progressed. There is really no need for you to employ such childish forms of self-expression such as you do below.
If you argue that the Magenta products are, based upon your experience, unuseable, what do you expect to happen? That someone in discussion with you who hasn't actually used those particular products will gainsay you? Of course not! As the inevitable result of your freely contributing to the design project (very brave for a trader who suggests that he is in "competition" with the project, I might add; good on yer!) I will react to what you say and change my proposals accordingly. That is normal progress in a civilsed technical forum.
For you to have introduced your experience and then to castigate me for taking on board what you have said is just silly. "Now, having had it pointed out to you that this was total cr@p, you start talking about using a different chip"? Have you been playing with Mr.Stevenson in the school playground again?
What you are stating appears to be a scare tactic to frighten everybody off from rolling their own electronics. If what you originally said had any import whatsoever, then the whole of the hobbyist electronic market would collapse, and your friend at Magenta would go out of business.
As to comments about Ham Radio, the whole point _IS_ to produce equipment that has _HUGE_ amounts of RF emissions.
Your preponderance of childish jibes would seem to indicate that you are now in a headlong panic that the hobby will realise how cheaply they can do things for themselves. Certainly you are not reacting in the way one would expect of a professional trader who has enjoyed a good trading period.
Not at all. There is no requirement for the hobbyist to behave as such. If there were, the hobbyist market would not exist.
When you were playing with the kits produced by Magenta, did you go out and spend £800 per day to have them certified?
Of course you did not.
QED.
If you must resort to silly childish jibes, then you can do no better than to take on the services of Mr.Stevenson as a tutor.
Do you mean to say that the very light duty example that you were parading at Donnington was a con trick? Were you not attempting to sell your goods based upon an illustration of how simple clock wheel cutting could become?
QED, once again.
Please go ahead, then we can all laugh at your failure and make you feel even more depressed. With a bit of luck you might even elecrocute yourself in the process and do the world a favour!
-- Steve Blackmore
No QED at all because they were not offered ON SALE to a MEMBER OF THE EEC
Before you spout one more piece of misinformation go to your local library and look up the rules on EMC for RETAIL items in the EEC. It's on CD there.
-- Regards,
John Stevenson Nottingham, England.
He does do, the monthly cheques are gratefully received.
NO QED again at all. Tonys Division master was designed to output 2amp so it wasn't a con. If it was only putting 1A out then it could have had problems. You program the output needed, a point you omitted off the third beer mat in your design. For the record I have one of these on a 6" brand new vertex table and it draws 1.8 amps at 24 volts. I also have one running on a large Hoffman table that weighs around 250 pounds. This one takes 75 volts at 7 amps using an external driver box.
-- Regards,
John Stevenson Nottingham, England.
Glad you brought up the clock wheel cutting engine that I demonstrated on the DivisionMaster stand at Donnington. The motor used for the dividing head is 140 oz-in, rated at 2A/phase as it happens. The other "light duty" application was the Sherline rotary table - probably the easiest table to drive that I have seen so far (and actually easier to drive than the dividing head on the wheel cutting engine, as it happens), as it has ball races on the wormshaft and on the table spindle, versus the plain bearings approach in the Vertex tables and on the worm shaft of the dividing head. Sherline themselves recommend (and sell) 140 oz-in motors for that table; in reality, the 100 oz-in motor that I used to demonstrate it works well enough, but it still requires 1.5A/phase. All the other motors I was using on the stand needed to be driven at between 1.5A and 2A. With the general trend away from L/R drives towards using bipolar chopper drives, it is increasingly hard to obtain decent motors that are rated as low as
1A/phase.Like I say, you clearly haven't tried to drive these sorts of machines with stepper motors. On the other hand, I have.
Regards, T>If you must resort to silly childish jibes, then you
Talk is cheap. If you think you can do it, get on with it.
Regards, T>If you're buying in maths libraries then perhaps that
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.