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Author Topic: Motor For Director Class Paddle Tug  (Read 12268 times)

Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #25 on: January 13, 2017, 07:25:22 pm »

Hi John and thank you for your help. Also thanks for the warning that the motors may overheat. If I do go ahead with my system I could drive the paddles at half speed to check on overheating or try the boat out for say 10 minutes and then check on the motors. You have got me worried a bit about my system. Is there a way of checking on overheating before I install them in the boat by running the motors outside of the model? I would need to put them under power I suppose? Any ideas I would be very grateful to run a test?  Thanks John with kind regards Colin D.
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John W E

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Re: Motor For Director Class Paddle Tug
« Reply #26 on: January 14, 2017, 10:14:56 am »

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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #27 on: January 14, 2017, 08:05:59 pm »

Hi John and thank you for the link. There are some interesting points. Still worried about the possibility of motors overheating under load. I received the 60 RPM motors this morning but I am going to keep these in my spares box for now as they won't be useable. I will now wait for arrival of the 200 RPM motors. Thanks again for the link that you sent. Regards Colin D.
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Danny

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Re: Motor For Director Class Paddle Tug
« Reply #28 on: January 15, 2017, 10:15:55 am »

A cheap and simple way of reduction is to use Meccano gears (plastic gears may also be suitable).
The shaft is divided inside the brass sleeve, under the oil hole, giving the ESSENTIAL independent control.
Mine had a paddle speed of 300 rpm which was a bit of overkill, but made manoeuvring very easy.  The geared load on the motors mean that they run very cool so no additional cooling was needed.
This method also saves on the cost of a sound unit - you can't hear it for the gear noise anyway! :)
If I were to do a paddle drive again, I would also use NON-feathering paddles!  The paddle going forwards pulls the hull down on that side, whilst the one going in reverse lifts the hull, this causes the boat to list excessively and spills the Captains tea!  %)
Cheers
Danny

Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #29 on: January 15, 2017, 02:37:27 pm »

Hi Danny and thank you for your message and picture. Your set up looks a very good system. I have ordered some gearbox motors which are fully enclosed. Please see earlier pictures. I am planning to install them with a direct drive as in picture. At the moment the motors installed   are rated at 40 RPM which hardly move the boat and the new motors will be 200 RPM. which I hope will make a big difference. My only concern is that they may over heat. What do you think? Also before going ahead with the installation is there any way of testing a motor that you can think of to see if it runs cool under load or not? Any help would be very useful. Regards Colin Duerden.
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John W E

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Re: Motor For Director Class Paddle Tug
« Reply #30 on: January 15, 2017, 03:51:08 pm »

hi Colin

The only reason I queried the motors that you are going to use was that you are the first one who I have come across who has used this type of motor on a direct drive paddle.  Under normal circumstances if the motoring gearbox is any good you generally find that three or four people have used this system. 

The only realy way to tell if the motors are up to it would be to put the model in the 'test tank' - i.e. the bath :-)  run the motors and keep an eye on them - obviously if they run hot within the first couple of mins where you are unable to touch them - you know they wont be any good - I think that is the best way to tell - unless you have motor specs

john
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #31 on: January 15, 2017, 06:06:56 pm »

Hi John and thanks for your advice. I will try this method in the bath with the 40 RPM motors to see if the motors get hot or not. If this is successful I will get the 200 RPM motors installed and assume they will not run hot. I will let you know what happened and then wait for the arrival of the motors in the post. Thanks again for your help. Regards Colin D.
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John W E

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Re: Motor For Director Class Paddle Tug
« Reply #32 on: January 15, 2017, 06:27:55 pm »

hi Colin

I think you may have the wrong end of the stick :-) its all to do with gear ratios; the 40 rpm motor will or should run cool - because due to the gearing, the paddles are  turning slower and putting the motor under less stress - therefore on the 200 rpm it has a higher gear ratio - and therefore putting the motor under slightly more stress - think of a car gearbox - you always start off in first gear/low gear - think what would happen if you tried to drive off in 5th gear from a standstill - it would put the motor under tremendous strain and stall the car - the same thing may be happening with your 200 rpm gearbox.

john
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #33 on: January 15, 2017, 07:38:00 pm »

Hi John I see what you mean. I have tried the bath test on the 40 RPM and I ran the motors for 15 minutes. No trouble at all motors were cold to the touch. But I am aware that the 200 RPM motors may behave differently as you suggest. One other idea has ocurred to me. What would happen if the motors were wired in series so the motors would use 3 volts each. Would  each motor  run at 100 RPM? Please let me know your ideas on this as this may be enough to power the paddles. I don't know which way to turn. Thanks again for for your help.  Regards Colin D
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malcolmfrary

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Re: Motor For Director Class Paddle Tug
« Reply #34 on: January 16, 2017, 09:34:16 am »

Yes they would run at a lower speed, probably 100rpm, but might be more susceptible to the load affecting performance.  Since the power input to each motor will be reduced, there might not be enough to give the performance required.
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #35 on: January 16, 2017, 10:32:36 am »

Thanks Malcolm I will bear that in mind. I will have to choose which motor to use as I have now ordered two 3 volt 100 RPM motors. At the end of the day I am going to finish up with a few spare motors for my spares box. Thanks with kind regards Colin D
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BarryM

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Re: Motor For Director Class Paddle Tug
« Reply #36 on: January 16, 2017, 11:01:42 pm »


Colin,
My Director tug 'Grinder' (photos elsewhere on the Forum) uses a pair of  MFA geared motors driving feathering wheels via separate ESC. The wheels can be independently controlled or switched to single joystick control. Although there is a working rudder I find that this is rarely called upon.
Paddle wheel rotation of about 120 RPM is ample for realistic speed and this is transmitted by toothed pulleys and rubber belt drive. I did start with Meccano gears and chains as a drive system but scrapped it when I found it created unacceptable radio interference.
Regards,
Barry



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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #37 on: January 19, 2017, 07:53:02 pm »

Hi Barry and thank you for your message. I am sorry not to have replied before now but I have been ill for the last three days. It was interesting to find out that 120 RPM was an ample speed for the power. I am going to install motors with a rating of 60 RPM and hope that would be enough. The other point being that these motors may over heat being gearbox motors. One point mentioned in the forum is that they will overheat but the only way to test this being to just try them. Heres hoping it can be worked out this way.  With Kind Regards Colin Duerden
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BarryM

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Re: Motor For Director Class Paddle Tug
« Reply #38 on: January 19, 2017, 08:15:37 pm »


Colin,
Perhaps I should have also mentioned that my model has feathering paddle wheels and 120RPM is the calculated 'out of water' speed. Once in the water this will drop to what? - 100 RPM?


If you are transmitting power on a 1:1 basis then my experience is that you will find 60RPM is too low and have to step up the revs by 1:2 gearing. Of course (?) you will not be motoring at full belt all the time.
What does the performance data for your motors say in terms of full load current?
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tobyker

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Re: Motor For Director Class Paddle Tug
« Reply #39 on: January 19, 2017, 11:31:58 pm »

a firm called motionco (search on web) does very nice toothed pulleys and belts.
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #40 on: January 20, 2017, 10:28:52 am »

Hi Barry and thank you for your message. I am planning to run the motors on direct 1:1 drive. I have not got any motor data. With the 40RPM motors on 1:1 drive it works reasonably well but a little slow but motors do not over heat and I was hoping that the 60 RPM may be enough and will not over heat either. This may gve a boat which moves 50% faster. This is what I am hoping anyway. The only thing to do is try it. ???
Also thank you toby for your message about motionco. Kind Regards Colin D.
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Re: Motor For Director Class Paddle Tug
« Reply #41 on: January 20, 2017, 10:42:50 am »

A good rule of thumb for deciding on a suitable motor and reduction ratio is that when on load, the motor should be running at no less than about 75-80% of it's unloaded RPM. Doing so indicates the motor is too heavily loaded.

If you can't measure the RPM, then measure the current being used when the motor is loaded.
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John W E

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Re: Motor For Director Class Paddle Tug
« Reply #42 on: January 20, 2017, 05:05:23 pm »

Hi ya there Colin,

Are these the motor gearboxes you are using to drive your tug? in the link below - I have been trying to work out the amperage draw underload on them.

https://www.aliexpress.com/item/25MM-DC-12V-160RPM-6V-80RPM-Motor-370-dc-gear-motor-Powerful-High-Torque-Gear-Box/32755377340.html?spm=2114.10010108.1000023.9.REjSxC

John

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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #43 on: January 20, 2017, 09:40:10 pm »

Hi John and thank you for message and link. Yes these are very similar but mine are shorter in length and are described as 6 volt gearbox motors and are in 3 types that are 40 RPM or 60 RPM or 200 RPM. These are on ebay but now I cant find them. So this may not be much use. Regards Colin. 
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #44 on: January 20, 2017, 10:22:54 pm »

Hi

 John I have found the exact wording to put into ebay uk to locate the motors these being   6V DC 60RPM High Torque Electric Gear Box Motor
Same again you should be able to locate with 6V DC 40 RPM High Torque Electric Gear Box Motor and again 6V DC 200 RPM High Torque Electric Gear box Motor. Hope this will locate the motors for you. I hope to hear from you soon. With regards Colin D
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malcolmfrary

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Re: Motor For Director Class Paddle Tug
« Reply #45 on: January 22, 2017, 08:46:48 am »

http://www.ebay.com/itm/6V-DC-200RPM-High-Torque-Electric-Gear-Box-Motor-/330738349135?hash=item4d018ab44f:g:0RwAAOSwoJZXSAhN
If tat is the right link and motor, It should guess that the motor is about the size of a CD player platter motor.  Since the overall size is about that of a plain 400 series motor (which does not have space taken up by a gearbox), I would guess that it would simply not have the power to do the job.  The other solutions have used a full sized 385 or similar, then added a gear arrangement.
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derekwarner

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Re: Motor For Director Class Paddle Tug
« Reply #46 on: January 22, 2017, 09:24:27 am »

The specification is given in the last page of thread text....Derek

______________________________________________________________________

"Swap out a poorly running or downright faulty gear box motor for this brand new, high quality 25mm, 6V, 20RPM replacement and give your electrical and testing equipment a new lease of life.

Benefiting from high torque and low noise, this motor is solidly constructed and ready to install in numerous applications.

Specifications:

•Torque: 20 N*cm

•6V DC

•20RPM

•Diameter: 25mm

•Length (excluding shaft): 45mm

•Shaft length: 12mm

•Shaft diameter: 4mm

•Weight: 72g

•Brand new and unused"
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #47 on: January 22, 2017, 12:45:34 pm »

Hi Malcolm Yes this is the correct motor at 200 RPM I am glad you have found the right one and the link leads you directly to the ebay item so thank you for that. In derek's dimensions printed  the speed mentioned is 20 RPM. It is NOT this one. It IS the 200 RPM which you have found. Regards Colin D.
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John W E

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Re: Motor For Director Class Paddle Tug
« Reply #48 on: January 22, 2017, 01:23:31 pm »

hi ya Colin

I am going to put a link on to MFA motors - have a look at the link - you will see a torque power of some of the geared MFA motors and basically what you require is a motor with a similar torque output - I have looked at the motors on Ebay using the links which have been put on by yourself and Malcolm - and I cannot find out what particular torque these motors are.



http://www.mfacomodrills.com/pdfs/919DLN%20series.pdf
John
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Colin Duerden

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Re: Motor For Director Class Paddle Tug
« Reply #49 on: January 22, 2017, 06:07:30 pm »

Hi John and thank you for your post I don't fully understand the torque ratings in the link you have sent me. However there is a torque rating in the post sent by derek warner showing specifications for a similar motor (see above posting by derek). It is for a motor of a speed of 20 RPM which I am not using but may be some guidance to someone like yourself who understands torque ratings. This rating is 20 N*cm. I wonder derek have you got this torque correct ie WAS it the 20 RPM or the 200 RPM. Could you clear this up? Best Wishes Colin Duerden
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