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[cassf1]

Hi

Just a quick question i have graupner 900bb none of the terminals are marked as positive, i have run this both ways with amp meter seem to pull about the same amps either way round so does it matter which way i connect them.

Thanks

[Stavros]

Not at all it will do the same job either way.I have never been fussy which way to connect the terminals on a motor for the simple reason if it is running the prop in the wrong direction one has to servo reverse anyway so what difference does it make.............in my opinion for all it's worth none at all ....make up your own mind


Stav

[cassf1]

Hi Stavros


Thanks mate your opinion good enough for me

[wombat]

Hi

Just a quick question i have graupner 900bb none of the terminals are marked as positive, i have run this both ways with amp meter seem to pull about the same amps either way round so does it matter which way i connect them.

Thanks

A lot depends on the type of the motor - positive is normally marked to indicate the direction of rotation - i.e. if you feed positive into this terminal the motor will rotate clockwise when viewed from the shaft end. It can make a difference if a motor is tuned to run in one direction - in this case even if the current flow is similar, the rotation speed in one direction will be higher than the other.

The fact you motor does not have an indication suggests it is neutrally timed and will run the same in both directions (though I am surprised positive is not marked ot give direction of rotation)

Wom

[warspite]

I found sometimes if no red mark a small square molded into the plastic end of the motor next to the terminal - don't know if this helps.

[cassf1]

Hi

Thanks warspite just looked at the terminals and the insulation around one is slightly L shaped so i will us this as positive

[warspite]

or in the case of this motor - which do you use the little circle or the indentation - hard to tell isn't it 

[malcolmfrary]

The markings if any just give a clue as to the likely direction of turn.  This will be important if using multiple motors and you want them counter rotating or not.
Best bet for getting them the wrong way round - DONT USE SERVO REVERSE.  Reverse the motor connections to get the prop shoving forward when you move the stick forward.  If you are running the ESC in permanent reverse, on some ESCs that have a relay reverse, you will be pulling considerable extra current from the RX supply, cutting run time.  Some ESCs have reduced performance in reverse.

[catengineman]

as an addition to malcolmfrary some ESC's also have a delay if operated in a reverse mode, had a twin screw boat (not mine) that needed rudder over to port to drive a straight line and seemed a lot stronger on thrust on one side more than the other and then berthing was not easy either, going astern the vessel also had some strange actions. I changed motors over (side for side) but the problem stayed the same? then by chance I used a different transmitter (without servo reverse) so had to change the wires over hey presto a straight running vessel with straight rudders!
took a while to find that one out.

So now I make sure I wire up my motors in the direction I want them to run and that way (with luck) my ESC's will also operate in the right directions

R.

[cassf1]

Thanks fellas well explained

[red181]

If  A brushed motor is second hand, then the brushes will have been "worn" or bedded in with the motor turning a certain way, so it might be worth making sure its still turning the correct way by means of the pos mark. I had a Graupner 9.6v motor new last year, it had no pos markings, and I asked the Graupner rep at the Ellesmere show last aug did it matter, he said it did, as the motors where supposed to run better one way. Trouble is, if its not marked, how do you know?/ other than amp or rev testing in both directions, Graupner rep could not answer that one, but on inspecting the motor he was suprised there where no markings