Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: portside II on December 20, 2006, 10:00:14 am
-
Hello forum has any one any ideas on what size /type /make of controller i will need to rum the motors on Greamsay (island supply vessel) ,had an electrinize fr15 in but seamed to struggle and blew a 10a fuse :( then tried a tornado marine 50a and that works but!! the starting speed is about 1000 rpm upwards :o ,as as there is no gearbox steady navigation around the pond is impossible any. :-\
ideas lads n lasses
-
First thing you need to do is find out how many amps the motor is drawing under full load (i.e. in the water). I recommend Mtronics controllers, I don't use anything else but that's jusr my opinion. Fuse should be rated at or just below the maximum current for the speed controller.
Hope this helps,
Scottie
-
thanks scottie that will help for a start ,i will have to do a bench test as she is not ready for the wet stuff yet
-
http://www.actionkit.co.uk/
Condor 20A ESC has "soft start" i.e. gentle acceleration from standstill. I have six of these and have never had any problems with them. BTW a 12 volt supply might be too much for this model/motor set-up, although you didn't say what batteries you are using.
-
thanks F.L.J.
i will hopefully be be using a 12v 6ah but she needs ballast then there will be two 12v 6ah's in her bowells .
The Condor 20a sounds good as a soft start is what i am after ,at the mo all i have tried is a electronize fr15 ,sea sprint 10 and that tornado but the less said about that one the better(nearly shook her to bits).
I have taken the tornado back to the shop and ordered an electronize 30a which is what i have in the big girl .
Thanks again will have a look at the Condor though.
daz
-
What voltage are you running on?
Bob
-
OK Bob
I will be on 12v as i find the higher the voltage the lower the amp's
-
portside II ,
Why I asked the question is that there aren't many true 540's that are rated for 12 volts.
If it is a genuine Mabucci it should be rated for 7.2 volts and 12 volts can cause problems with overheating of the armature windings and brush gear.
540's also can have huge stall currents (some in excess of 90 amps) so it is crucial to protect the circuit with fuses for whatever speed controller you use.
Even using the new Vipers, which are advertised with thermal protection, use fuse protection.
Bob
-
I guess that's what I was trying to say without me sounding like a smartaR5e (Bob says it much nicer anyway). Twice the volts generally equates to something like twice the RPM, so there would be a problem with low-speed handling. The only 540s I've ever run on 12 volts were a 6:1 geared one in Envoy and another on direct drive which I rewound with about 100 turns of much thinner copper wire.
The other solution to high currents might be to use two ESCs - see the article on twin motors under Electric Motors on the main Mayhem website. Go on; gi yer sen a treat - it's Christmas!
Season thingies.............and, of course, suit yourself 8)
-
right thanks lad's will have to look into what i am doing ,didnt know about the imput voltage for the motors had them running the other day in the test tank and the 30a electronize worked fine and after 10mins running at a reasonable speed the motors were still coldish and there was no smell ,also the esc was only just warm so it could be ok i am running a pair of rabosche (if thats how it's spelt) props 4 bladed 50mm
I maybe am running with the devil working the motors at 12v
A friend of mine said on asking about running the robbie bow thruster which is rated at 7.2v ,that it would be ok through a esc on12v as its the current/amp's that kills them not the voltage .
I may be wrong but am thinking about electric fence controlers high volts 20,000 low amps 50-100ma
any more imput please
thanks Bob and F.M.J.
-
If you are looking for 12 volt motors, try Model Motors Direct 777's, they are fine on 12 volt, or the Model Slipway geared 550's.
Bob
-
For a set load, the more volts, the more current. The cattle fence has a very high resistance load (until a cow rubs up against it), so there is very little current flowing.
If you apply 12 volts to a 6 volt motor, it will take twice the current, and thus give four times the power. The downside is that it will also get very hot, very quickly, and let out the smoke that makes all electrical devices work. If you run a 7.2 volt motor on 12 volts via an ESC, then the 12 volts will be switched on and off very rapidly, and hopefully, as long as you do not exceed the motor rating by turning the power up too far, it will have time to cool off in the switched-off time.
The only time that the "more volts, less amps" rule applies is when the load can be varied (i.e. use a different motor). In this case, for a given amount of power, a 12 volt motor running on 12 volts will require less current than a 6 volt motor on 6 volts giving the same power.
Hope this helps.
-
thanks Malcolm
the motors are 7.2v i think? and they have a cooling fan built into them they are also none free running ,that is to say when you try and turn them you can feel the pull of the magnet's inside .at the moment they are connected via four wires ,one to each motor terminal .Would it make any difference if i linked the motors together +to- and the the remaining + - to the esc or which ever way to produce counter rotating motors - to-,+to+ if you know what i mean?.
-
Aaaaaaaaargh!
These sound like the dreaded fan-cooled 550 nightmares which have bedevilled the members of this forum for eons (well, a couple of months). Friendships have been made and lost over these motors. Portside - these motors are NOT suitable for 12 volts, irrespective of what you may have read or been told about them when you bought them. If it were down to me I'd have the world's supply of these things destroyed - or at least labelled clearly "NOT suitable for model boats if run on more than 6 volts". Research the threads of this forum if you require further members' experiences of them; it's not just my opinion.
Take my advice and cut your losses; buy some proper motors e.g. from Electronize or any retailer who sells Graupner Speed 600 ECO motors.
For wiring see article on main Mayhem website http://www.modelboatmayhem.co.uk/Common/Electrics/Images/setupsA4JPG.jpg
Suit yourself, mate - but these are really poor fare.
-
Try not to use timed motors "the type they use in cars" as they only run one way efficiently.
Peter
-
FLJ, apart from Ms. Sinbad and a couple other rogues, you're one of the few who actually sticks some decent punctuation in your scribes.
But while you're on the subject of motors, when I were younger and stupid'er, and before learning how not to buy a motor, the smoothie in the shop swore that the 540 was rated for 7.2v. "Look... it even says 7.2v on the box!". It did. So that clashes with your statement. But, if truth be known, I didn't believe a word of his so-called patter - or the bumph written on the box. And even though I was skint at the time, and a ten-quid motor meant a lot to loose, I still bought it. A boating desperado HAS to have his motor and he HAS to know how it works, right? So I shoved 7.2v up there.
It died shortly after.
Nope - not being pernickety, it's just an observance of how misleading certain information can be. But from the stuff that I have learned, I'd put my money on what you said already.
Portside, if you've got your ears on, buy that man a drink. Not just for his grammatical skill, but for steering you in the right direction.
Last word to FLJ...
If you don't mind my asking, what swg did you use on that 100-turn rewind?
-
I've been asked (via email) to add this to the discussion.....
These are pictures of the rogue 550 fan-cooled motors which have caused several members some grief over the last year. They are available on E-Bay as well as at shows and from certain retailers. The legend on the can says simply “Johnson”; there is no further ID except the numbers around the flux rings (which mean nothing to me). These are three-pole motors with an internal plastic cooling fan which can be seen through the slots in the case just in front of the brushes. The backplate is a dark grey metal casting as opposed to the usual 540-style white plastic moulding or silver-coloured steel pressing. The case is substantially longer than a stock 540 – some 65mm from end to end, and the motors have two steel flux rings pressed around the forward half of the case.
We have found that the motors are not suitable for “normal” scale models if run at anything over 6 volts. For example, one member has two of these things fitted into a Graemsay ferry and has discovered that he has “low speed handling difficulties running from 12 volts” – probably the understatement of 2006. Another member reports that the stalling current is astronomical and I can personally vouch for the high current consumption, even at relatively low speed on 7.2 volts. They also get very hot very quickly and should be water-cooled for all installations.
In short I wouldn’t recommend anyone to buy one of these unless they are very familiar with all aspects of operating high-speed DC motors. Indeed, the only reason I have one to photograph is that it was given to me. Personally I wouldn’t install it in anything but a wheelie bin………but suit yourself, eh?
-
Well said Martin. The fact that some retailers will sell you these things without blushing as they do it, just goes to prove how suspect 'expert' advice can be from some people in the model trade.
Do I win a prize if I guess correctly who sent you that e-mail?
"Suits you sir!"
-
Do I win a prize if I guess correctly who sent you that e-mail?
"Suits you sir!"
Kayem
Is there nothing which escapes your eagle eye and razor wit? I'm afraid no cigar this time, matey - someone called Anmo has already rung in with the right answer......... 8)
FLJ
Portside II
I'm sorry this has wandered off thread - blame Kayem - but the technical bit above holds true; you can cheerfully ignore the persiflage which follows it...but suit yourself anyway ;)
-
Oh dear thanks for the doom and gloom ,i wonder what next year will bring .Don't worry about the diversion ,i'ts nice to wander .
right let's se if i can recall some sanity i have taken one of the motors out of gramesy for you all to look at they are marked as
www.huntersystems.co.uk
RS540SF
fan cooled 27x1
order code HS3
and if the pic comes up all the better as they don't look like the ones posted by Mayhem (well not from this angle)
AM I DOOMED?? ??? ;)
-
Portside
You're right! They're not the Johnson fan-cooled type. I have a sneaking feeling they are Sun motors. Strangely the Hunters Systems website doesn't list them any more - well, I couldn't find them anywhere. I wonder if they were a job-lot? I haven't come across fan-cooled Sun motors before but I did once have a couple of Sun 3-pole 540-sized ones which were very snappy indeed. I gather that Sun are a cheap copy of Mabuchi motors and are fitted in cheapo rechargeable drills etc from the ROC.
As to whether you are doomed I can't say for sure! I would imagine that any motors which have internal fans are going to run fast and furious, which isn't what you really want for a workboat. Why not try them on 6 volts anyway - what have you got to lose? If they're still nasty and spiteful then save them for the MTB and try a couple of the new 5-pole Electronize 545-12 motors. They look just right for your model and they should fit straight into it with no modifications.
Suit yourself, sir.......it's a free country!
-
thankyou F.L.J. at last some good news well at least better will have a go at 6v the other thing i would like to know is ,on the setup link you posted it dont show what i asked for ,that is if i can/cannot wire the motors together as one and if not why as this would (i think) reduce the voltage i have put a sketch on here ,a bit basic but !!
-
Portside. This would give each motor 12 volts and double your trouble. The amps would double and the ESC would need to be twice as big IE. 30 amps ( at that price too !!)
Fulleatherjacket, can you tell me about the motors you mentioned please ( 5 pole 545's) Would these be better for my 'Aziz' instead of the 540's that I currently run. Where can I find out about these, IE price and details etc.
Hope you can help
Cheers...Ken
-
Ken
PM on its way. For anyone else, just Google "Electronize". I don't think 545-12 motors would be man enough for Aziz, which has 50mm x 4-blade props running in fixed Korts. Better using the recommended ones, which are geared 540s from Slipway.
Portside
Wiring the motors in series should give 6 volts across each; your diagram shows them in parallel. Having said that, I would personally never use one speed controller for two motors unless they were very low-current jobs and/or the model was too small to carry two ESCs. I have to emphasise that this is purely a personal opinion and so I don't want to get into a tangle with anyone who feels differently. Life's too short and, like I always say, suit yourself anyway.
-
;D
-
As a personal opinion, I would always avoid connecting motors in series. The result is that both motors get the same current, but due to the fact that it is impossible to guarantee that both motors are equally efficient, and that both are identically loaded, one will "win", and hog power from the other. This makes for a boat that will be determined to sail in circles.
-
When wiring 2 motors in series AND using them with contrarotating propellers(one motor reversed), won't one motor be MUCH more efficient than the other... something to do with motor / commutator timing?
Another 540 (Speed 600) sized motor to consider are:
'Model Motors Direct's - 555
'MFA's' - RE - 550/1 (3 POLE )
..... and if you really want to 'push the boat out'.... a medical motor like the Charles Austen Pumps motors! ( aka CROUZET motors)
A real Rolls Royce motor! - A friend gave me a "bad" 2nd hand motor and it's still better than anything I've seen before... then again, a 540 motor at £93 each plus VAT!!!!
Have a look at the Farnell website to see what real motors are available.... if your pocket is deep enough!
http://uk.farnell.com/jsp/search2/browse.jsp?N=500015+1004985 (http://uk.farnell.com/jsp/search2/browse.jsp?N=500015+1004985)
-
Great list on Farnel, Martin. You're right about 'pockets' though.
Another question springs to mind. What revs are the norm for model boat propulsion. I appreciate that it depends on the prop, but I was thinking of the noise level. Being a Volvo driver, I'm not used to hearing the engine, and wondered if this could be carried over to model boats.
Cheers...ken
-
one will "win", and hog power from the other. This makes for a boat that will be determined to sail in circles.
When wiring 2 motors in series AND using them with contrarotating propellers(one motor reversed), won't one motor be MUCH more efficient than the other... something to do with motor / commutator timing?
Yep! That's at least two of the reasons I can think of...........any more offers?
Logic and experience both say 2 x Motors = 2 x ESCs + 2 x Batteries + 2 x Rx outputs + 2 x sticks on the tranny (you'll need steering and throttle with a mixer). Owt less is more trouble, especially for a relative novice to the game.
-
gOD I HATE COMPUTERS
i had wrote a reply and at the lend of it after i had done the spell check decided to insert a smiley then post it
and thats all you got ,a smiley!.
thanks for the imput F.M.J. thats what the forum is here for and all imput wheather good or bad is greatfully recieved will have a think about what i am doing with the motor set up and maybe put a couple of electronise 540's in with a pair of bearing shafts .
will keep you all posted
daz
-
As a rule of thumb, for scale boats with scale props somewhere between 2500 - 3000 rpm.
Small tugs with large props less, fast partol boats more.
Deccaperms run about 2750 from geared end.
Bob
-
Thank you Shipmate 60
Happy new Year
Cheers...Ken
-
Whoa some of the parts for this hobby are pricey enough without looking at motors from the Farnell website ,damn they are expensive some of the geared motors would make great radars and a fully operational towing winch (just make sure it's strapped down).
A big thanks to Mayhem Martin and all the members who give their knowledge so freely .
A happy new year to you all :D
-
Looking at the motor in question, it looks like the motors shipped with the Club500. Having a brief look on the Johnson web-site for matching motors, the closest match seems to be for ride on cars. In this case the stall curent is around 90Amps
The critical factor on this motor, and the similar ones are rated for operation at a maximum of 9V - they are designed for operation off a 7.2V pack.
Tim the Wombat
-
Oh dear thanks for the doom and gloom ,i wonder what next year will bring .Don't worry about the diversion ,i'ts nice to wander .
right let's se if i can recall some sanity i have taken one of the motors out of gramesy for you all to look at they are marked as
www.huntersystems.co.uk
RS540SF
fan cooled 27x1
order code HS3
and if the pic comes up all the better as they don't look like the ones posted by Mayhem (well not from this angle)
AM I DOOMED?? ??? ;)
Hi Guys
Just to let you all know that the motor in question is not the dreaded 550 that alot of people have had problems with. It is, as the label says RS540-SF and comes from the Mabuchi stable via the States as it is not imported in this country apart from by us. It is a fan cooled 27 turn motor that due to its physical built-in fan runs cooler than most motors. The idea is that the cooler a motor runs the more inefficient it is - this relates to less power loss and higher revs. (you get more running time for your bucks).
It has a wider voltage range too 4.8 to 12 volts. And yes, it is available at the above on-line shop.
Hope this clears up the questions
-
Hi all, good information from Shipmate60
Many years ago I made a tachometer to measure rpm of model boat props.
It came in useful when trying to get the power right on a steam driven "Streamlinia" 40 inch launch. It was using a 50mm brass prop. It needed 1800 rpm to just about plane. The steam plant could not maintain this power, which was about 30lbs cont.
So I converted to electric, I had a Duplexcraft 9 volt motor (550 size) with a gear reduction of about 2.3 : 1 and 12 volts applied. Running quite cool at the high end of its' rev range, not possible with a direct drive to this size prop.
Current (measured) was 2.8 amps so giving just under 30 watts of power and she planes very nicely with rpm of 2000, and used to run for about 25 mins. from a 12 volt 3Ah SLA battery.
I could have used a smaller propeller but the gear box looks a lot like a steam turbine and now has a "plastic" boiler to hide the battery and maintain the fiction of steam.
I have one of the dreaded motors mentioned above (a gift), I have never used it as it is only useful at about 3 volts which means that you would need to use a mechanical controller, but that, if matched electrically would work.
Some years ago Model Boats published an article on the 540 family of motors. If you can get the 4 numbers that follow, i.e. 540 / 5 / xxxx (5 pole motor) I think the first pair of x's are the armature wire dia. and the 2nd. pair the number of turns on the armature.
For model boats look for lots of turns on the armature like 30+.
The low number of turn motors give high acceleration characteristics useful to model cars.
The "higher voltage less current and more efficient" remarks earlier are applicable to say the Graupner or Marx range of motors where there is a similar power design motor available at different voltages. Then it is mainly the lower losses across the brushes at the higher voltage that make them a few % more efficient.
The reference to the Farnell motors shows precision motors intended in the main to be used as servo motors. All good motors, but unless you buy in bulk too expensive.
I would suggest that model boats do not need precision motors to drive a propeller in a pond. But if you can get them cheap then great.
Our friends at Model motors Direct and Electronize have looked through the 1000's of different specs of motors, and suggest specific motors for various tasks.
I take their advice! It is simpler in the long run.
Hope I have not gone on too long, regards to all, Roy
-
thankyou Hunter
i shal keep the motors in Greamsey as they are running ok and just getting warm and not hot like some of the other motors available at least thats all cleared up .
cant fault them and the electronize 15a esc runs them together
daz
-
It takes a worried man.....
I was sold a pair of the "rogue" Johnson 550s pictured by Martin as speed 600s to power a perkasa on 6v, and advised they would give a moderate planing performance as opposed to 700s which would cost a lot more, but would give superb performance. Do I fit them anyway and restrict them to 6 or at most 7.2 V, or am I wasting my time? Are they intrinsically bad motors, or can they just not take more than 6V?
-
Tobyker
There's nothing intrinsically bad about the Johnson motors. As someone pointed out earlier, they are supplied with the Club 500 racers. It's just that they are not suitable for, say, a scale ferry or trawler - especially on 12 volts. Planing boats are a different matter. As you've bought them then why not give them a shot, but keep the pack size down to 6 cells? Water-cooling might be a good idea as well, although not perhaps vital.
Maybe you'd let us know how you get on?
Good luck.
FLJ
-
Thanks, FLJ - I'll press on and report back idc. I wonder if the problem is that some people are trying to get too much torque out of them in heavy scale boats?
-
They run OK up to 7.2 volts and are fast, 9000 plus if my memory is correct, anything over 7.2 volts and they draw excessice currents.
Bob