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Author Topic: Switching outrunner motor for  (Read 3293 times)

Siftasam

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Switching outrunner motor for
« on: January 12, 2013, 12:12:55 AM »

From siftssam, would like to use a outrunner in a straight runner, but how to switch it? Want to use this motor because I have been given it , it has been suggested that I might use a servo tester, any bright ideas would be welcome,
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Subculture

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Re: Switching outrunner motor for
« Reply #1 on: January 12, 2013, 04:32:35 AM »

A servo tester would be a simple solution. You could also make unit around a 555 timer chip if you're electrically inclined, or use something like Picaxe if you can code.

malcolmfrary

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Re: Switching outrunner motor for
« Reply #2 on: January 12, 2013, 10:12:42 AM »

Presumably a servo tester driving the ESC?
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Stavros

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Re: Switching outrunner motor for
« Reply #3 on: January 12, 2013, 09:55:49 PM »

Now I have though tof this and YES a servo swinger will work to drive the Brushless esc BUT what I think will happen is that when you immerse the prop in the water there will be a massive amp draw and could poss damage the esc UNLESS you get a very big esc.One of the best motors for straight running is a 900 series running on 24v and a 55mm 2 blade prop
 
 
Dave
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malcolmfrary

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Re: Switching outrunner motor for
« Reply #4 on: January 13, 2013, 10:29:13 AM »

The thread title says "outrunner" which implies a brushless motor despite this being the brushed motor section.  Not knowing the size, type or performance expectations of the boat in question, I would hesitate to offer a suggestion about a suitable brushed substitute.
A brushed motor in a straight runner has the advantage of not needing a controller, but a brushless motor would need an appropriate ESC and something to generate a control signal for the ESC.  Of course, it is possible that if one was not given with the motor, buying an ESC could cost more than a suitable brushed motor.  The brushless ESC is, in effect, the motor brushes as well as the speed control.
If the combination of prop, motor and ESC is correctly rated for the battery being used there should be no problem.
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Tug-Kenny

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Re: Switching outrunner motor for
« Reply #5 on: January 13, 2013, 11:37:01 AM »


You are correct Malcolm.

We've now moved it over to here.

Cheers

ken

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inertia

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Re: Switching outrunner motor for
« Reply #6 on: January 13, 2013, 11:48:55 AM »

'Steamboat Phil' Abbott uses these for that very job http://www.action-electronics.co.uk/pdfs/P22.pdf
Just set the knob to neutral, switch on the main power, turn the knob until you reach the motor speed you require and then let go.
The kit for P22 is around a tenner; built and tested it's 12 (and I make no commission on them at all!!).
DM
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Mrs Stav

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Re: Switching outrunner motor for
« Reply #7 on: January 13, 2013, 01:33:02 PM »

Beg to differ with yuo but I know for a fact Phil has not installed one in a straight runner at the moment as Phil and I were discussing the surge of amps issue not so long ago,so at the mo is untestedin practise BUT it works on the bench
 
Dave....on Kellys llap top !!!
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inertia

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Re: Switching outrunner motor for
« Reply #8 on: January 13, 2013, 01:48:39 PM »

Beg to differ with yuo but I know for a fact Phil has not installed one in a straight runner at the moment as Phil and I were discussing the surge of amps issue not so long ago,so at the mo is untestedin practise BUT it works on the bench
 
Dave....on Kellys llap top !!!

The surge of amps will happen whatever method you use to ramp up the speed controller, and any modern ESC will be designed to withstand a sudden inrush of current (unless it's Chinese and has those tiny little inscrutable Amps they so love). The slower you do it then the less of a problem it will be, but you can't get away from the fact that turning a prop in water is a load on the motor and will draw current. The servo swinger will be quite unaffected by this as it controls only the power supplied to the logic side of the speed controller, not the high-power side.
............... and get out of Kelly's lap - you'll break her!

DM
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Re: Switching outrunner motor for
« Reply #9 on: January 13, 2013, 02:18:00 PM »

Krafty Kelly is letting Dave use her laptop to rack up her posts.
At 25 posts she will be putting Dave's fleet
on the sales page  %% {:-{

Ned
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Stavros

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Re: Switching outrunner motor for
« Reply #10 on: January 13, 2013, 06:24:42 PM »

Ned stop giving her IDEAS as she has ALLREADY taken over some of MY shed to build her boat  O0 O0  And she is doing it all on HER own :-)) :-))
 
inertia I agree fully with what you have said...BUT with any straight runner we do not usually use a speed controller just a switch and a batt...I know that the ACTion servo swinger will take it BUT it is the speed controller especially if it is of Chineese origin that is what I have my doubts...but it someone is going to use a chineese one then make sure it is at least a 100 Amp one
 
Dave
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Siftasam

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Re: Switching outrunner motor for
« Reply #11 on: January 15, 2013, 10:59:06 PM »

Many thanks to all who gave some thought to the question of switching a brushless motor , having read all your answers, I am more confused than ever, beginning to think that at nearly eighty I had best stay with steam, but with the price of copper now,and the cost of silver solder, not to mention the demise of glr,kennions with whom I have had an account for over fifty years, looks like I will have to spend the winter fuel allowance on an graupner 900 brushed motor for my new wedge, length 62ins beam 6ins, first problem, where to get said motor , next, what cells to use,to give say 10 mins running time, thank you for reading this rather garbled post, your thoughts would be much appreciated,






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Stavros

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Re: Switching outrunner motor for
« Reply #12 on: January 15, 2013, 11:23:10 PM »

Right then Young Sir I think I am suitably qualified to ans your questions as I know what I am about to say is the truth.
 
Dont get the Graupener 900 it is to expensive BUT all is not lost....Give Steve Tranter a ring at Steve's Model boat bits and he will sell you a caldecraft 900....same thing  :-)) :-)) :-)) :-))
 
Prop wise all you will need is a std plastic 2 blade 55mm prop....dont belive me then ask Steam Boat Phil
 
Batts well thast simple really...Component shop 12v Nimh 4300mah stick packs
 
Running time well TBH you should get around 30 mins of straight running with a wedge....I know for a fact that Phil and Myself have run His 1 mtr boat at Wicksted at least 30 times up a 70m Straight running course.
 
You will obviously need to run this Motor on 24v (that is 2x 12v packs) and Water cool it....If you can not make a cooling coil then just pm me and I will make you one as they are not commercially available.
 
 
Dave
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Siftasam

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Re: Switching outrunner motor for
« Reply #13 on: January 17, 2013, 12:38:45 AM »

Would it be possible that someone out there would be good enough to do a drawing showing what brushless motor I should need to power a wedge class boat approx 62 ins long 6 ins max beam to move at just under the max speed allowed 12 mph, being an old duffer I need a wiring diagram showing what wire goes where, and what components I shall need, ie servo tester, ESP, cells etc, many thanks to Stavros for help offered, afraid the motor he suggested is no longer in production by the way Stavros I was speaking to steamboat phill at the mpba grand regatta about his very quick metre class boat, very impressive, he was interested in my steam wedge, he questioned me about the boiler, and was congratulatory when I got three bulls, thanking all for interest shown
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inertia

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Re: Switching outrunner motor for
« Reply #14 on: January 17, 2013, 08:51:23 AM »


inertia I agree fully with what you have said...BUT with any straight runner we do not usually use a speed controller
Stav
The difference between a brushless and a brushed motor re speed controllers is that you can just connect a brushed motor to a battery and run it that way. The brushless ESC is essential - without it a 3-wire brushless motor simply will not run. I'm prepared to be corrected by anyone who knows better.
DM
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nick_75au

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Re: Switching outrunner motor for
« Reply #15 on: January 17, 2013, 10:35:47 AM »

That is correct, the ESC takes the place of the brushes and commutator in a brushed motor, the motor is electronically commutated instead of mechanically commutated, in all other respects the motors are the same including a surge of current as a sudden load is placed on the motor.


Nick
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inertia

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Re: Switching outrunner motor for
« Reply #16 on: January 17, 2013, 11:42:17 AM »

Like this.
You'll need an ON/OFF switch between the battery and the ESC to power up the whole shebang. The Servo Swinger is used to increase the speed of the motor until you get to what you need, then let go of the model. This will actually reduce the sudden surge of amps if you put the model in the water to start with e.g. a straight runner.
Trust me - I used to make these things.
DM 
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Re: Switching outrunner motor for
« Reply #17 on: January 17, 2013, 12:27:39 PM »

Most servo controllers I have seen and used provide their own 5 volt feed (not much use otherwise!), so generally you want to isolate the 5 volt line from the esc.

Siftasam

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Re: Switching outrunner motor for
« Reply #18 on: January 19, 2013, 01:13:50 AM »

Many thanks , but I still don't know what motor to purchase, and I suppose a servo swinger is a servo tester,  these seem to come in 6 and 12 volt, what do I need, I have a fear of seeing some expensive equipment going up in smoke and of me having no idea why! Thanks to all who have tried to help
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inertia

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Re: Switching outrunner motor for
« Reply #19 on: January 19, 2013, 10:17:30 AM »

I suppose a servo swinger is a servo tester,  these seem to come in 6 and 12 volt, what do I need,
See my first post on this thread above.
As regards a suitable motor, I have no experience of using brushless motors so the floor is open to anyone who has.
DM
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malcolmfrary

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Re: Switching outrunner motor for
« Reply #20 on: January 19, 2013, 12:06:02 PM »

I suppose a servo swinger is a servo tester,  these seem to come in 6 and 12 volt
All of the servo testers that I have seen have been for use on 5 volts, equals the normal 4 cell battery pack for a receiver.  Many ESCs will have a circuit (the BEC) built in to provide this 5 volts from the main battery, be it 6 or 12 volts.
Some servo testers do some extra automated tricks, moving the servo through a pattern.  For this job, this is not needed, just the simplest tester will do the job, e.g. the ACTion one.
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nick_75au

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Re: Switching outrunner motor for
« Reply #21 on: January 20, 2013, 01:11:37 AM »


Straight running is not a model boat activity practised here so I'm slightly clueless to the performance requirements, but going by the steam video on youtube the boats are travelling at displacement speeds, 12 MPH maximum speed according to a previous post.

OK, for the motor, with a 55 mm prop I would reckon a 800 Kv out-runner motor that is 36 mm in diameter.


http://www.giantshark.co.uk/xyh3548-790kv-brushless-outrunner-p-404598.html
as an example.




I think that this motor on around 6-8 volts would be good, you can, if using Nimh change the voltage by increasing or decreasing the cell count to achive the desired speed to a reasonable extent, Li-pos have a bit to big a jump in voltages when your experimenting. A 3800 mAH pack should easily get 1/2 hour total run time.[size=78%] [/size]To use a higher pack voltage then a lower Kv motor would be required or 2:1 gearing on this motor


Nick
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