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[DJW]

Afternoon All


So back in the 70's my first build was a Sea Urchin, I recall it being smallest of the Keilcraft (?) range and so most affordable. Unfortunately that boat has been lost over the decades since, but I have thought about it from time to time...  So I plan to build one again, and try to keep it roughly of the 60's / 70's era when it was designed.


I see SLEC are making the kit available, so that's where the hull will be sourced.  I've also been looking into how to power it, and I like the idea of using a Taycol motor.  To that end I managed to pick up a pair of Taycol Comets on a well know auction site for just over £20.00, they are boxed but have been used and need some restoration as neither are running at the moment. They are the ungeared versions.

















I've done some initial reading up on the Taycol range, some references over past few years in Model Boats magazine, and the excellent resource for all things Taycol at http://taycol.tk/ ( [size=78%]http://taycol.tk/[/size][size=78%] )[/size]


The Comet uses a permanent magnet rather than being 'field wound' like most of the Taycol range so I think can be treated like a normal brushed motor, I'm sure the universe will make sure I regret my assumptions at a suitable point...


And in the spirit of winding back time.  The RC unit will be my old 4ch Fleet (Fleet Control Systems) Unit which dates to the early 80's, it will have a Corona 2.4Ghz module added (on it's way from China as I type...) to bring it up to date.  Also needed as the Taycols were I believe great at creating RF interference that should be handled better by 2.4Ghz systems.  Out of courtesy to everyone else on the lake I'll be adding suppression as part of the Taycol renovation..!


I did start out with a 2 channel Waltron RC on 27Mhz back in the day, but again it's been lost to time, so the Fleet is the oldest I have.





This is going to be a slow burn build with a few hurdles on the way I think.  I'd like to get at least one running Comet from the two units that I have, of course two would be better, depends if I need any donor parts.  Then get the RC updated and working before starting on the boat build.  That's current plan anyway.


Anyone who's worked on a Comet or can advise on refurbishing the Taycols in general, well input and advice would be gratefully received.  Same with the Fleet update, I've heard it's a good unit to take the upgrade, but would be good to hear from anyone who's actually done it.


We shall see...
David.

[Treble]

David , If you get stuck , please note that I have a number of working and tested Taycols for sale . Also note that previously published information that certain models cannot be reversed is incorrect . From memory the one I managed to reverse is a Target . No problem in digging out the circuit to do this , though it was some considerable time ago.. Again from memory it involved removing the supplied links and feeding via external cables , thus allowing for the motor to be reversed .

[dodgy geezer]

The Taycol site contains a fair bit of info on refurbishment (as well as several methods of reversing all the Taycol motors with current ESCs). Yours is a permanent magnet motor, so will have no problems with this anyway.


I would check several aspects of each motor, and maybe swap components to get the best result.


You want the best magnet.  Both are probably pretty poor by now. You need to pay attention to the commutator and brushes - the least worn commutator should be picked. The site contains instructions for making new brushes - you may find the old ones are workable. Try moving the shaft
up and down to see which end plate bearings are least worn.


Lubricate the brushes and run the motors with a bit of a load to see how much sparking you get. Sparks put a lot of interference out, both on the RF spectrum and down the power leads to the ESC. The site has advice on suppression. That will probably be your biggest problem. And remember metal-to-metal interference if you are using 27MHz. Interference down the power lines can cause problems even if you are using 2.4GHz, of course, and in line inductors can be useful here...


Good luck!

[Circlip]

"AeroKits" David.


  Regards  Ian.

[Martin (Admin)]

 
Sea Urchin: https://slecuk.com/product/sea-urchin-16ins-406mm/

[DJW]

Good Afternoon All


Thanks for the support and Taycol info.  I'll be taking a look at the Comets first and will post progress updates.


David. 

[roycv]

Hi, as Dodgy has said the magnet will be less than it used to be.  I have not tried this on my Comet motor, but on an old Trix motor, I just added a small (8mm) neodimium magnet to one of the poles and it rejuvenated the motor.
If you run 2.4Ghtz it will probably not need the usual capacitors, BUT whenever you come near another electric model boat you will introduce RF interference to the esc and any non-2.4Ghtz RC model.
I still use 27 and 40 Mhtz RC equipment so I hope we do not 'meet' on the water!Roy

[Abandon Ship]

If you know anyone into vintage model railways, you might be able to find someone with one of these:


https://www.youtube.com/watch?v=0A-hLYS9RvU


Don't know if your magnets will fit, but it could be a way to maintain originality rather than going down the neodymium route. 

[Circlip]

Have a PDF copy of a "Model Engineer" design showing construction of a remagnetizer which looks incredibly like the one above. Anyone who fancies a copy, supply E-mail address via a PM (DON'T publish e-mail address's on open forum)


  Regards  Ian.

[dodgy geezer]

.......
If you run 2.4Ghtz it will probably not need the usual capacitors
.....

It's a good idea to use caps to cut the sparking as much as possible. The sparks send a huge jolt up the power lines into the ESC, and that can cause a lot of trouble to the controls. It's not only RF you have to worry about...

[HMS Invisible]

It would seem odd for DJW to use an esc over a rheostat control after picking a retro motor and Tx.

Suppression capacitors don't cut brush arcing, but higher frequency pwm escs do.
So if you want to suppress the arc and maximise brush life, avoid low frequency pwm (~50Hz) controllers. That would include PIC processor based controllers, post Y2K, where the designer didn't immediately make the obvious desirable jump to > 500 Hz pwm.


 

[DJW]

Morning All


Interesting comments, thanks for the input.  I'd thought the only RF interference issue to be addressed was interference with the controlling radio system (mine and others in vicinity...) and I intend to address this part of the problem by adding suppression and using 2.4Ghz.  I'd not realised there were considerations with the ESC used.  I'd also not really given thought to rheostat or ESC as a speed controller yet, does anyone have any specific hardware recommendations that have been proved to work with this motor type..?  My thought had been to 'look' like a vintage build, but with 2.4Ghz control, modern servos / lightweight batteries, maybe 3D printed fittings so I'm not too worried about speed controller being authentic, just functional as it can be hidden / disguised.


I had briefly wondered about the magnets on the Comets and how to rejuvenate them if needed, that train related re / demagnetiser is interesting and seems very effective.  And @Ian, I'll be contacting you for those plans, thanks for the offer.


I did power up one of the Comets yesterday on a bench PSU as the shaft was pretty free running, not much play at all in the bearing surfaces and it looks fine apart from being dusty. It ran first time, plenty of arcing and sounds like a bag of nails.  But it runs and I'm happy with that, I ran it briefly at 5V and pushed the current to 2A.  The second Comet does not rotate as freely and may have a cracked paxolin end plate, so I didn't attempt to run it, I think a stripdown is in order now for both units for some clean up and lubrication and see where that leads.


Thanks again for the comments.
David.

[dodgy geezer]

Interesting comments, thanks for the input.  I'd thought the only RF interference issue to be addressed was interference with the controlling radio system (mine and others in vicinity...) and I intend to address this part of the problem by adding suppression and using 2.4Ghz.  I'd not realised there were considerations with the ESC used.... 

The Radio Frequency emissions from the sparks do cause problems at 27MHz which are minimised by the use of 2.4GHz. But the sparking can also produce spikes at the battery voltage back down the power lines - and sometimes, with the field-wound motors, considerably higher voltages due to induction.  This dirty power can have all sorts of unwanted effects. Sometimes I have been able to avoid it by not using the ESC BEC, and powering the receiver with a separate battery.  However, I think the problem can be worse on a field-wound Taycol with a poor commutator - a permanent magnet Comet may have less powerful spikes (though I don't like the sound of the bag of nails!)...

I did power up one of the Comets yesterday on a bench PSU as the shaft was pretty free running, not much play at all in the bearing surfaces and it looks fine apart from being dusty. It ran first time, plenty of arcing and sounds like a bag of nails.  But it runs and I'm happy with that, I ran it briefly at 5V and pushed the current to 2A.  The second Comet does not rotate as freely and may have a cracked paxolin end plate, so I didn't attempt to run it, I think a stripdown is in order now for both units for some clean up and lubrication and see where that leads.


Note that, if you want, you can mount a small ball-bearing in each of the paxolin end-plates. Not authentic, but should result in much smoother running...   

The Taycol site not only has lines for cutting new paxolin end-plates, but also for creating a new commutator! These motors were assembled very simply by hand using stamped components - in some cases on a kitchen table (private communication with Taylor's grand-daughter). So it would be fairly authentic to replace the commutator and brushes with home-made items. Once disassembled, it would be interesting to see photos of the commutator and brushes. Don't run without lubrication of the brushes if you can help it...

[HMS Invisible]

dodgygeezer, the sparks are not the cause of any problem. They are only the visible indicator of chopping current at the stall rating of the motor.

Morning All


Interesting comments, thanks for the input.  I'd thought the only RF interference issue to be addressed was interference with the controlling radio system (mine and others in vicinity...) and I intend to address this part of the problem by adding suppression and using 2.4Ghz.  I'd not realised there were considerations with the ESC used.  I'd also not really given thought to rheostat or ESC as a speed controller yet, does anyone have any specific hardware recommendations that have been proved to work with this motor type..?  My thought had been to 'look' like a vintage build, but with 2.4Ghz control, modern servos / lightweight batteries, maybe 3D printed fittings so I'm not too worried about speed controller being authentic, just functional as it can be hidden / disguised.
...

  My point was to avoid 50Hz pwm controllers and don't experiment with cap values in the hope of suppressing sparks.
   Most Chinese manufactured escs these days are fixed at 1kHz or 2kHz.
Mtroniks run at ~ 3kHz, FR40 has a 4kHz setting.
Hobbywing 1060, among other model numbers have an 8kHz pwm setting.

This 12 to 24 volt resin-pottable esc has a fixed 8kHz pwm and 8volt l.v. cutout.
https://www.aliexpress.com/item/1005003766285546.html
The going rate is ~ £14 for 100 sale days out the calendar year.
Use the Find Similar button or come back at the next sale date to see better pricing.
 

[dodgy geezer]

dodgygeezer, the sparks are not the cause of any problem. They are only the visible indicator of chopping current at the stall rating of the motor.

They are an indication of the state of the brushgear, and I have found that the worse the sparking, the greater the disturbance to a connected ESC. On a bad Taycol the current is probably being interrupted continuously, even while the brushes are passing over the contact area of the commutator... 


I take your point about the higher-frequency ESCs, however. These are likely to be better-designed all round and better able to withstand a dirty power line.  I tend to run with 'Cheap Chinese', and these are probably very susceptible to any disturbance.

[dodgy geezer]

Have a PDF copy of a "Model Engineer" design showing construction of a remagnetizer which looks incredibly like the one above. Anyone who fancies a copy, supply E-mail address via a PM (DON'T publish e-mail address's on open forum)

  Regards  Ian.

Circlip - if you send a copy to the Taycol hotmail address (see bottom of the Taycol Tales section of the site) I can add it to the list of useful items for Taycol refurbishments...

[HMS Invisible]

They are an indication of the state of the brushgear, and I have found that the worse the sparking, the greater the disturbance to a connected ESC. On a bad Taycol the current is probably being interrupted continuously, even while the brushes are passing over the contact area of the commutator... 

You can further beef up suppression to round off corners of problem transients, improve matters, yet still have the same firework display at the motor. Again, sparking at the brushes is a related symptom, but not a cause.
 I don't share your specific reservation regarding Chinese escs.  However, a surface mount linear bec sharing a 1" square pcb with drive transistors is an inbuilt week point that kills escs at 12v input and 1/2 amp servo load on the bec. But that is also the same corner cut by a UK brand fabricated in China.
 The esc I linked at Aliexpress has a 3-amp switching bec so does not cook the drive transistors supplying high bec current at high input voltage.
 You'll now see switching bec offered on some small budget Chinese escs.

[ChrisF]

David, it will be strange reading about you building anything other than a Riva! But interesting.

Chris

[dodgy geezer]

You can further beef up suppression to round off corners of problem transients, improve matters, yet still have the same firework display at the motor. Again, sparking at the brushes is a related symptom, but not a cause.

Alas, I have a dicky scope (hoping for a new one for Xmas!). When I get it, I will be able to have a look at the power leads with/without suppression...

I don't share your specific reservation regarding Chinese escs.  However, a surface mount linear bec sharing a 1" square pcb with drive transistors is an inbuilt week point that kills escs at 12v input and 1/2 amp servo load on the bec. But that is also the same corner cut by a UK brand fabricated in China.

I suspect that my operative word is 'Cheap'. Most of my boats are small and low-cost, and so ESCs at under a fiver are what I use a lot of. Mostly, they work. But I rarely use 12v...

[roycv]

The re-magnetizer is for very small OO gauge open frame magnet motors.  The unit works by sending a large current into coils for a second at most. like a Zap.  I looked at making my own but decided it was too dangerous!
I think there is an article on-line from Model Engineer magazine 70+ years ago using very large capacitors that discharge through 2 magnetising coils with the magnet to be zapped in between.  It looked dangerous!
When industrial size magnets are moved on lorries by rail they are only magnetised when they are in the location where they are situated.  The equipment to magnetise them is moved with them and the work done in situ and then the magnetising unit is taken back to the manufacturers.
You are not allowed to transport very large magnets.  That is the law I don't think it has changed.
I think experimenting with neodimium magnets is cheaper, they sell at 50 at a time.  So cheap to try out. 
Some 40 or so years ago I made my own unit for OO gauge railways that would burn its way through anything on the track that stopped the current getting to the loco.  I worked out a circuit I think it was a Colpitts oscilator that only worked if the track to loco circuit was broken then it oscillated and produced a large AC voltage between the loco pick-up and the track.  I connected it up and it would cut through dried paint on the rails.
I left it in use with our son using it.  One day there was a separate problem and my bare arm touched the track and I got a hell of a shock.  My oscillator was turning out 1400 volts AC!  It was disconnected and broken apart it was dangerous.
The small unit referred to was over £100 when I checked some years ago.  It was cheaper to get the motor/magnet done by post with a company specialising in the job.
Interesting though.
Roy

[roycv]

Hi Dodgy you have a PM
Roy

[HMS Invisible]

Alas, I have a dicky scope (hoping for a new one for Xmas!). When I get it, I will be able to have a look at the power leads with/without suppression...

I think you'll find high frequency digital storage scopes are needed to pick up that stuff.

Next best pondside tech toy after a handheld scope is a dc current capable clamp meter. £14.34 is the discounted price for those new to the store. I don't need another, but I checked that is a hall effect type that does d.c.
Some reviewers have not sussed you have to store a reference zero reading before each true reading.https://www.aliexpress.com/item/1005005757085279.html

I suspect that my operative word is 'Cheap'. Most of my boats are small and low-cost, and so ESCs at under a fiver are what I use a lot of. Mostly, they work. But I rarely use 12v...

I was seeing them for just over a pound each during the last sale.

[DJW]

Afternoon All


I did have a quick look at the PDF sent over by Ian for the magnetiser, and must admit I wasn't quite prepared for the '...the draw will be around 110 Amps, so use a large battery...'  !


Moving on.  Here are a few pics of the Comet.  First the brushes, and to me they don't look too bad at all.





And the Commutator








Doesn't look too bad to me, this is as removed so I'll clean it up and post the results.  There could be some damage maybe done by the arcing to the commutator, see the 9 o'clock position where the brushes have been running.


The coils look OK but some of the varnish (?) is peeling away, is that an issue..? Shaft has no apparent damage or grooving so should clean up OK I think.








Any other observations..?


Best regards
David.

[Circlip]

...the draw will be around 110 Amps, so use a large battery...'  !"  - - - - - Rubber gloves and a hazmat suit


  Battery IS a car battery and you only give it a pulse, Never zapped the whiskers from a DEAC?


 Copy gone Dodgy.


  Regards Ian.


  Looking at this, just shows how the instant gratification era has pampered today's muddlers.

[Martin (Admin)]

 I might have missed it... have you powered up the motors as yet?

  How do they run?