MOTOR CUTTING OUT WHEN USING RUDDER

[andrew greenfieldParticipant @andrewgreenfield50901]

Hi all new to this boating game . but i have a boat that i have just finished . but when running it up at 1/4 throttle and using the rudder the motor just cuts out . and the only way to get it going again it to turn off then on again the esc . could this be the motor drawing to many amps or the servo

[andrew greenfieldParticipant @andrewgreenfield50901]

[TelstarParticipant @telstar]

Hi Andrew You will need to give more information before anyone can make a good guess at the problem.

 

What radio gear, Esc, batteries etc. and perhaps a picture of the layout.

Lots of guy’s on the forum are willing to help, but we do need a little more

 

cheers Tom

[andrew greenfieldParticipant @andrewgreenfield50901]

well i am running a johnson 600 motor with 110amp esc off 12v 2.1amp battery . 27mhz 3 channel radio gear . but i think i may have found the problem . the motor i got off ebay . and i have found some reports that say they arnt 2 good and draw to many amps . so i am going to change the motor over for a graunper speed 600 with a reduction gearbox . i need longtivity not speed you see . what sort of prop size would be best . the boats about 3ft long v hull

[Colin BishopModerator @colinbishop34627]

A 2.1 amp battery is very small for that size of hull. Depending on the shape I would think you need a bigger one. From what you say, the motor won’t have helped either.

 

The effective capacity of a lead acid battery is about half the nominal amperage so you need to take that into account too. You may be better off with a 6 volt battery or a 7.2v NiMH pack and a low drain motor if you are only looking for modest speed. What type of model is it? A three foot tug is quite a big model but a thre foot destroyer will weigh less than half as much.

 

Colin

[Bob Abell 2Participant @bobabell2]

Andrew

 

Does the motor still cut out when you don`t touch the rudder?

 

Bob

 

[andrew greenfieldParticipant @andrewgreenfield50901]

the boat itself is a bait boat for fishing . i put a speed 600 motor in this afternoon but that starts to smoke at half throttle so no go there i think . i have used high torque servo for the rudder . is it worth changing to a normal servo ? . and Andrew the motor dosnt cut out if i leave i dont touch the rudder . i would prefer to run 12v if possible . you see i have a lot of 12v batterys lying around

[Bob Abell 2Participant @bobabell2]

Hello Andrew

 

Just had a thought!

 

Is the rudder fouling the propellor?

 

Bob

[Colin BishopModerator @colinbishop34627]

As Bob suggests, if the motor is smoking and stopped it sounds as if it is jammed.

 

Colin

[TelstarParticipant @telstar]

Hi Andrew

 

Try disconnecting the coupling and propshaft from the motor and try it, this would confirm or eliminate any mechanical problems

 

 

Tom

[andrew greenfieldParticipant @andrewgreenfield50901]

Hi Bob/colin . i think the motor was faulty . prop etc is all ok , have now installed a mfa 540 motor . this seem to be so much better . no cutting out , think i will also change the servo to a normal one . the high torque one was a little bit overkill i think ( came out of one of my fg marders used for steering . what prop size would you recomend ?

[Dave MilbournParticipant @davemilbourn48782]

Andrew

Don’t run the MFA motor shown on 12v; the bearings won’t last very long (more smoke for you). Servos described as High Torque these days are frequently the “digital” type which draw a lot more current than the “normal” type, so I would advise using a standard cheapo job such as the Futaba S3003.

Dave M

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Hi Andrew,

must agree with dave – those MFA motors shown state 3 – 9V – and to me that means 6 – 7.2V if on maximum throttle for any length of time. No motor is designed to run at its max voltage for extended periods, and you are trying to run 3V over the recommended.

 

Kimosubby.

[ashley needhamParticipant @ashleyneedham69188]

Andrew. Graupner do a speed 600 that is for 12v, and couple this with a two blade plastic 35mm prop “S” pitch if poss, or an ordinary brass 3 blade type..should give adequate performance.

 

Also, ensure your propshaft setup is not binding, or one of the nuts is loose, leading to possible tightening up when rotating.

 

Ashley

[andrew greenfieldParticipant @andrewgreenfield50901]

i think the picture was wrong just for reference . it states the following 4.5-15volts on the spec . i would on very few ocations be running at a full 12v . would the 35mm prop still be ok with this ? .

MFA RE-540/1 3 -Pole DC Motor

Low Drain High Power Motor
Operating Voltage 4.5 to 15 volts.
Current approx. 2.85A at max efficiency.
RPM at 6/12V – 6180/13360 at max efficiency.
Weight 146g (approx) Shaft Diameter – 3.2mm (1/8″)
Part No: 457RE540/1
More Information…

[ashley needhamParticipant @ashleyneedham69188]

Yes, on both counts, motor rating (for 12v) and also prop; a 35mm prop would be ok, at least, they are ok on a couple of boats I have with those MFA motors.

 

Dont use an “X” pitch prop though, not very efficient at lower speeds.

 

Ashley

[andrew greenfieldParticipant @andrewgreenfield50901]

what amp battery would be best . at the moment i have some 2.1amp and 4amp ones

[ashley needhamParticipant @ashleyneedham69188]

Big as possible, really depends on the size hole you have for the battery, and the weight the boat can carry. Lots of different size batteries available (as gel types) for all fits.

 

Ashley

[andrew greenfieldParticipant @andrewgreenfield50901]

ok new motor instaled . swoped the servo over to a normal one . now the servos are twitching more and more as i increase speed . and when on full throttle the rudder servo goes all the way over on one side and then the motor cuts out again . ohh and i am running 6v now

[Dave MilbournParticipant @davemilbourn48782]

This sounds like a classic case of interference from the motor brushes (that MFA motor is particularly prone to it). Have you fitted RF suppressors to the motor? Could you take a photo/photos of the installation and post it here so we can see what the problem might be?

DM

[andrew greenfieldParticipant @andrewgreenfield50901]

the motor came with suppressors allready on . they did look a little small for the job though . is it worth moving the reciever further away from the motor ? i will upload some pic tonight

[andrew greenfieldParticipant @andrewgreenfield50901]

well heres a few photos of my set up . i have used alli for mounting the servos and metal posts . these are screwed to plywood . esc is a 100amp one . just a thought could the alli be one of the problems maybe amplifying the interferance from the motor ?

[ashley needhamParticipant @ashleyneedham69188]

Andrew.  MFA do sell suppression kits… 3 capacitors, one big `un across the terminals and one each smaller ones from each terminal to the casing. If yours has one between the terminals already then just the ones from terminal to casing will have to be fitted. I have never understood why the motor capacitor Graupner sell (the yellow one) is so LARGE??

Sometimes, I find in some of my boats (as room is tight) I get interference and it`s simply sorted out by seperating the wires a bit. Try not to cross too many wires to the reciever.

To run through the list of things you COULD do..

Suppress motor with capacitors,

Ensure seperation of wires especially reciever ariel,

Earth motor body to water via a strap from one mounting screw to the propshaft body (needs a bare bit of shaft to contact the water)

Twist motor wires together,

Use a ferrite core (from Maplins for instance) around motor wires,

Use seperate battery pack to power reciever,

ummm…

 

To be honest, I have loads of boats and the most I have had to do is suppress the motor with capacitors.

Ashley

 

 

Edited By ashley needham on 16/02/2012 20:33:27

[Bob Abell 2Participant @bobabell2]

Andrew

I suspect the problem may be the aluminium baseplate?

Temperarily remove it and see what happens?

Before going down Ashley Avenue!

Bob

[andrew greenfieldParticipant @andrewgreenfield50901]

Well i think it may be sorted . i have changed the mount to a plastic one . also change the motor to a 3-9v mfa . and reduced the battery to 6v/10ah . and all seems ok . all i have to do now is try it out on the lake , i would still like to run 12volts though but a least its running ok

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