Help Needed Please! Electric Machine Fault.
- Thread starter AES
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ajs
Established Member
AES
Established Member
Wildman
Established Member
a simple thing but I hope you did a test to see that the on/off switch is in fact operating
AES
Established Member
If anyone is interested, the full write up on removing the PCB from this machine can now be found in the "Miscellaneous How To" section. When I've finished writing it, I'll do a similar post in the same area on how to remove the motor. Hopefully within the next few days.
Cheers
Cheers
AES
Established Member
Inspector
Nyuck, Nyuck, Nyuck!
Hmm. 
Now you have me wondering what is under the hood of my old Canadian made 30" machine. Part of me wants to see what is under the hood to compare and the other part is insisting I leave sleeping dogs lie. The other part is a lot louder. 
Pete
Now you have me wondering what is under the hood of my old Canadian made 30" machine. Part of me wants to see what is under the hood to compare and the other part is insisting I leave sleeping dogs lie. The other part is a lot louder. Pete
AES
Established Member
Hmm.
Pete
Pete, I know JUST what you mean Sir! Believe me I wouldn't have even dreamed (nightmared!) of going there id the machine hadn't suddenly gone "phut"!
Inspector
Nyuck, Nyuck, Nyuck!
I think mine is a doodle to open up. It has a tilting table with a fixed frame. The control box with innards in attached to the base with cables going to the motor and wall. Entirely self contained rather than built into the frame like yours. Motor has a belt to the shaft and arms at the rear of the machine. Might pull the box cover screws tomorrow to see if the board resembles yours.
Pete
Pete
The thread has pricked my curiousity about the history of these machines.
It turns out the original design and build was Canadian and then there have been several companies involved.
A post by King Canada company who were directly involved, tells the history in a good level of detail.
https://www.scrollsawvillage.com/articles/resources/excalibur-scroll-saw-what-happened-r101/Editing this down a little for the non American market, the timeline seems to be :
1982 - Somerville Design of Canada introduces the Excalibur scroll saws manufactured in Toronto Ontario. The saw becomes well regarded.
2003 – General International acquires the assets of Summerville Design including the Excalibur brand. G.I. sends the 21” scroll saw to Taiwan to be manufactured.
2014 + or – G.I. is sold to DMT holdings of Seattle WA. Including the Excalibur brand but not the manufacturing rights for the scroll saw. They are held by the manufacturer in Taiwan.
2015-16 - JPW ( the parent co who own the Jet, Powermatic and Wilson brands) designs their 22” saw and has it manufactured by the same Taiwan maker as the original Excalibur saws.
2016 + or – The original Taiwanese manufacturer seeks new North American distribution for the original design scroll saws. King Canada is granted distribution rights to the original 16”, 21” and 30” saws for the Canadian market, branded Excelsior in Canada and King Industrial in the U.S.
2017 – Seyco introduces a version of the saw manufactured by the same maker as the Excalibur, Excelsior, King Industrial and the JPW saws.
The Seyco and the JPW (Jet) saws are designed after the Excalibur saws with proprietary differences.
2017 - The European saws Axminster, Pegas, etc., are all made by the same Taiwanese maker. These saws were previously supplied to them by G.I.
2018 + or - General International (DMT Holdings) begins to market a Chinese made version of the 21” saw under the Excalibur name and model number.
So depending on which variant of the saw @AES has, the design of the electronics could be Canadian, Taiwanese or Chinese and the basic circuit upto 40 years old.
The biggest break in the history seems to come in 2018 as General International (DMT) did not own manufacturing rights to the original designs and presumably their Chinese made saws from this date share only the Excalibur name with the original machines.
It turns out the original design and build was Canadian and then there have been several companies involved.
A post by King Canada company who were directly involved, tells the history in a good level of detail.
https://www.scrollsawvillage.com/articles/resources/excalibur-scroll-saw-what-happened-r101/Editing this down a little for the non American market, the timeline seems to be :
1982 - Somerville Design of Canada introduces the Excalibur scroll saws manufactured in Toronto Ontario. The saw becomes well regarded.
2003 – General International acquires the assets of Summerville Design including the Excalibur brand. G.I. sends the 21” scroll saw to Taiwan to be manufactured.
2014 + or – G.I. is sold to DMT holdings of Seattle WA. Including the Excalibur brand but not the manufacturing rights for the scroll saw. They are held by the manufacturer in Taiwan.
2015-16 - JPW ( the parent co who own the Jet, Powermatic and Wilson brands) designs their 22” saw and has it manufactured by the same Taiwan maker as the original Excalibur saws.
2016 + or – The original Taiwanese manufacturer seeks new North American distribution for the original design scroll saws. King Canada is granted distribution rights to the original 16”, 21” and 30” saws for the Canadian market, branded Excelsior in Canada and King Industrial in the U.S.
2017 – Seyco introduces a version of the saw manufactured by the same maker as the Excalibur, Excelsior, King Industrial and the JPW saws.
The Seyco and the JPW (Jet) saws are designed after the Excalibur saws with proprietary differences.
2017 - The European saws Axminster, Pegas, etc., are all made by the same Taiwanese maker. These saws were previously supplied to them by G.I.
2018 + or - General International (DMT Holdings) begins to market a Chinese made version of the 21” saw under the Excalibur name and model number.
So depending on which variant of the saw @AES has, the design of the electronics could be Canadian, Taiwanese or Chinese and the basic circuit upto 40 years old.
The biggest break in the history seems to come in 2018 as General International (DMT) did not own manufacturing rights to the original designs and presumably their Chinese made saws from this date share only the Excalibur name with the original machines.
MorrisWoodman12
Established Member
From AES's replies I surmise he is an excellent Mechanical engineer who has absolutely zero electronics knowledge (apologies AES if I've oversimplified things). Could it be that the manufacturers are similar? An outstanding mechanical design and build but rely on external electronic design services? And once they have what they see as a suitable design component that they really don't understand, they just keep using it without being aware of the potential of newer components and techniques.
That could be the problem, because they are the best leading brand then like so many other companies that get to that position they just stop product development until one day they get woken up by the competition and then have to play catchup, always best to have continous ongoing product development to just keep that one step ahead of any competitors. The electronics were good in the day, simple concept of you set the switch on point and it always switches of at the zero crossing point so effectively chopping lumps out of the sine wave and ties them into that low voltage motor. Things have progressed, just they cannot see any value in doing so at the moment, for some idea of modern processors I am working with a dsPIC that is no bigger than your thumbnail but can provide upto sixteen complementary PWM outputs which can be used for all types of motor control and syncronous rectification and the baby of the family has just 28 pins and is much smaller which would be ideal for speed control of these type of machines.
AES
Established Member
Well Morris. That just about sums it up!
I did learn some very basic electrics and electronics as a school kid, and later on, during my apprenticeship. And still later I learnt a lot about how electrics work, mainly in modern airliners (AC & DC). But NEVER to the extent of knowing what actually goes on inside the various black boxes, just what they do. And of course, how to find out which black box needed replacement and how and where to find a "new" one!
That's it.
As to your "EXCELLENT" re mech eng, thank you very much Sir! Though I didn't fully appreciate it at the time, the apprentice training I got was actually first class, and fortunately, a lot of that has stuck, even though I started that course back in 1961.
I did learn some very basic electrics and electronics as a school kid, and later on, during my apprenticeship. And still later I learnt a lot about how electrics work, mainly in modern airliners (AC & DC). But NEVER to the extent of knowing what actually goes on inside the various black boxes, just what they do. And of course, how to find out which black box needed replacement and how and where to find a "new" one!
That's it.
As to your "EXCELLENT" re mech eng, thank you very much Sir! Though I didn't fully appreciate it at the time, the apprentice training I got was actually first class, and fortunately, a lot of that has stuck, even though I started that course back in 1961.
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Looks like it went peatong in around 2014, mass produced in Taiwan and sold in a few liverys which we are all aware of with the current line up of various machines with different badges. This is probably why there is no product development as there is no competion, yes my XL700 does come to mind and sales are good so again down to the customer who is still buying. We all complain about different aspects of the machines but are still buying .
ajs
Established Member
I did want to reply to multiple recent posts but can't remember how to get the multi-quote thing to work, particularly across page separations, so I'll just summarise my thoughts instead.
This is a design that has clearly evolved over time - e.g. those vertically mounted highish power resistors clearly were not the ones originally specified, they have been substituted at some point for cost or availability reasons but the board design has not been adjusted to fit. People are criticising it as being antiquated technology but to be fair I don't really see that - the board as shown clearly lacks sufficent switching components (transistors etc) to be carrying out much of the underlying logic. I suspect it is that daughterboard with the surface mount doing all that, from what I can make out that could easily be a microcontroller based approach. It could date from perhaps 1990 onwards but I think it more likely post-millennium.
What I do see is that it's been built to a price and seemingly to be assembled with basic equipment, I believe this is a hand populated wave-soldered board, probably no more than a dozen people on the assembly line doing fairly unskilled work. It isn't inappropriate if you want to keep that in house and are shifting low thousands of machines a year.
The "cheap" part is eliminating an isolated power supply. I've spent the day on and off considering how I would do this. If I was doing this in quantity 1 (i.e. minimise design effort) I'd proably throw a biggish torridial transformer on in it and crudely smooth it with biggish caps. Transformer would be perhaps £30 and caps £10 in qty 1, perhaps a quarter of that in bulk. I wouldn't bother regulating the motor drive since it's of no benefit so using common values for parts you'd end up with a supply that varies between perhaps 55-65V over the mains cycle (using a 48V transformer) but it would be isolated from the mains.
For series production I'd probably spend the time to nut out a switch mode supply. I'm not an expert in such things but could probably cook something up inside a week with a few hundred pounds of whatever components take my fancy. Rough guess for BOM would be £10 for the supply only in unit quantities, half that at scale.
Pulse width modulation (turning the motor on and off rapidly) isn't a bad approach for controlling this kind of motor, it gives good slow speed control and preserves torque at low speed. It's the approach I would take. As I think it was Spectric commented, I'd use a microcontroller to do that but vary it between on 0-100% of the time at ~60V instead of 0-25% of the time at four times its specified voltage. I made something similar as a hobby project while still at Uni for controlling model trains, with a switch of transistors that would be a simple drop-in for this job.
If the pressure to reduce the BOM was too great and had to drop an isolated supply I may go for a similar overall approach for the motor drive but at least power the control circuit from a small, cheap (£2 by the unit) board mounted transformer and feed the control signal to the mains side with an optoisolator (20p). That would at least mean the entire circuit isn't potentially live. I'd also take a careful look at board layout since that one doesn't appear to conform to the minimum spacing (3mm) between mains traces on a PCB. Even then I'd have reservations, particularly as I noted yesterday you need to ensure the motor windings are good for mains from an insulation perspective, even at that reduced duty cycle.
Yes, it works and presumably works well, but I wouldn't feel comfortable signing off on it.
Sorry, it seems everything I post on this ends up as an essay answer.
This is a design that has clearly evolved over time - e.g. those vertically mounted highish power resistors clearly were not the ones originally specified, they have been substituted at some point for cost or availability reasons but the board design has not been adjusted to fit. People are criticising it as being antiquated technology but to be fair I don't really see that - the board as shown clearly lacks sufficent switching components (transistors etc) to be carrying out much of the underlying logic. I suspect it is that daughterboard with the surface mount doing all that, from what I can make out that could easily be a microcontroller based approach. It could date from perhaps 1990 onwards but I think it more likely post-millennium.
What I do see is that it's been built to a price and seemingly to be assembled with basic equipment, I believe this is a hand populated wave-soldered board, probably no more than a dozen people on the assembly line doing fairly unskilled work. It isn't inappropriate if you want to keep that in house and are shifting low thousands of machines a year.
The "cheap" part is eliminating an isolated power supply. I've spent the day on and off considering how I would do this. If I was doing this in quantity 1 (i.e. minimise design effort) I'd proably throw a biggish torridial transformer on in it and crudely smooth it with biggish caps. Transformer would be perhaps £30 and caps £10 in qty 1, perhaps a quarter of that in bulk. I wouldn't bother regulating the motor drive since it's of no benefit so using common values for parts you'd end up with a supply that varies between perhaps 55-65V over the mains cycle (using a 48V transformer) but it would be isolated from the mains.
For series production I'd probably spend the time to nut out a switch mode supply. I'm not an expert in such things but could probably cook something up inside a week with a few hundred pounds of whatever components take my fancy. Rough guess for BOM would be £10 for the supply only in unit quantities, half that at scale.
Pulse width modulation (turning the motor on and off rapidly) isn't a bad approach for controlling this kind of motor, it gives good slow speed control and preserves torque at low speed. It's the approach I would take. As I think it was Spectric commented, I'd use a microcontroller to do that but vary it between on 0-100% of the time at ~60V instead of 0-25% of the time at four times its specified voltage. I made something similar as a hobby project while still at Uni for controlling model trains, with a switch of transistors that would be a simple drop-in for this job.
If the pressure to reduce the BOM was too great and had to drop an isolated supply I may go for a similar overall approach for the motor drive but at least power the control circuit from a small, cheap (£2 by the unit) board mounted transformer and feed the control signal to the mains side with an optoisolator (20p). That would at least mean the entire circuit isn't potentially live. I'd also take a careful look at board layout since that one doesn't appear to conform to the minimum spacing (3mm) between mains traces on a PCB. Even then I'd have reservations, particularly as I noted yesterday you need to ensure the motor windings are good for mains from an insulation perspective, even at that reduced duty cycle.
Yes, it works and presumably works well, but I wouldn't feel comfortable signing off on it.
Sorry, it seems everything I post on this ends up as an essay answer.
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AES
Established Member
UPDATE:
New PCB arrived today, correct, plus the 2 x extra fuses. Fine, except that I doubt I'll have time to install and test before I go travelling for a week.
BUT:
Also included was a 2nd PCB, completely different to mine (even physically larger, and only 3 x retaining screw holes as opposed to my 4 off), plus several bits of cable, some with in-line fuses (no such thing on my machine), etc.
Called Dictum and they told me to keep all the extra stuff (or throw it all away). Strange!
Anyway, as quite a few of you seem to have got a lot of interest (enjoyment?) from discussing the electronic aspects of my machine (even though I have myself only understood less than 10% of it) then I thought you'd like to see the new, MUCH different PCB.
Here (alongside my correct and the removed PCBs):
As anyone can see, even me, the "extra" PCB is MUCH different to the original.
"Enjoy" (!!)
Cheers
AES
New PCB arrived today, correct, plus the 2 x extra fuses. Fine, except that I doubt I'll have time to install and test before I go travelling for a week.
BUT:
Also included was a 2nd PCB, completely different to mine (even physically larger, and only 3 x retaining screw holes as opposed to my 4 off), plus several bits of cable, some with in-line fuses (no such thing on my machine), etc.
Called Dictum and they told me to keep all the extra stuff (or throw it all away). Strange!
Anyway, as quite a few of you seem to have got a lot of interest (enjoyment?) from discussing the electronic aspects of my machine (even though I have myself only understood less than 10% of it) then I thought you'd like to see the new, MUCH different PCB.
Here (alongside my correct and the removed PCBs):
As anyone can see, even me, the "extra" PCB is MUCH different to the original.
"Enjoy" (!!)
Cheers
AES
From the labels stuck on the big inductor and capacitor of the green PCB we might deduce that at least those parts, if not the circuit board are made by MeanWell, a very reputable manufacturer of switched mode power supplies used for LED lighting, servo and stepper motor power supplies and more.
If the green one will fit, use that
If the green one will fit, use that
AES
Established Member
Well, it wouldn't be a huge job to make a couple of mechanical mods so that it will fit - physically that is. But what about wiring it up? Everything (I mean cables, etc) look much different. Frankly I would know where to start, and the machine itself is not exactly "portable"!From the labels stuck on the big inductor and capacitor of the green PCB we might deduce that at least those parts, if not the circuit board are made by MeanWell, a very reputable manufacturer of switched mode power supplies used for LED lighting, servo and stepper motor power supplies and more.
View attachment 169545
If the green one will fit, use that
The green PCB is itself marked www.atm.ch. Don't know if it's relevant in this case, but usually on internet, E-mail. etc, ".ch" usually means Switzerland! (Like the "GB" sticker on the back of UK cars, mine has a "CH" sticker. Means the same thing (this car is registered in "GB" in your case - in Switzerland in mine). But you're right, at least a couple of the bigger components are marked exactly as you've shown above.
P.S. Following the above "link" for "atm" it does indeed come up as a Swiss company specialising in "industrial automation" (amongst other things) and they're based in a place called Greppen, not far from Luzern, about a 1 hour drive from me. Perhaps "someone" has been monitoring this thread and has noted all your electronics criticsms.
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MorrisWoodman12
Established Member
Since atm is a Swiss company perhaps they can supply a circuit, well at least a connection diagram. It's worth a try.
Martin
Martin
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