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Author Topic: ESC Performance  (Read 1671 times)

sea.mariner

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ESC Performance
« on: March 12, 2009, 08:42:20 AM »

Having recently purchased a 50amp ESC on the spec sheet it quotes ' 50amp in forward and 20amp in reverse' if I was to connect this to a bow thruster would it give the same amout of power in both directions or 100% in one and less (40% ish) in the other direction ? I would like to find out before I start fitting it. Thanks in advance, Dan.
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derekwarner

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Re: ESC Performance
« Reply #1 on: March 12, 2009, 10:02:36 AM »

Dan....I am a steamer  {-) but think  :o :o :o

1) you could apply a load that created the same power in FWD or reverse...as long as either did not exceed 20 AMPS
2) you could provide a load in FWD that did not exceed 50 AMPS
3) you could provide a load in reverse that did not exceed 20 AMPS

These are rather large current values  >>:-( especially for a bow thruster.........what sort of scale are you considering???????????????????

Ideally,,.........the current draw for a bow thruster would be = in both directions........Derek
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Derek Warner

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FullLeatherJacket

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Re: ESC Performance
« Reply #2 on: March 12, 2009, 10:57:58 AM »

Having recently purchased a 50amp ESC on the spec sheet it quotes ' 50amp in forward and 20amp in reverse' if I was to connect this to a bow thruster would it give the same amout of power in both directions or 100% in one and less (40% ish) in the other direction ? I would like to find out before I start fitting it. Thanks in advance, Dan.

Dan
Save it for another model; it will only do as you suspect when used as a Bow Thruster controller. This thing was designed for model cars, irrespective of what you may have inferred from the blurb or been told by the supplier.
I suggest you purchase one which was designed for a model boat instead. PM me for further info, or suit yourself.
FLJ
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andrewh

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Re: ESC Performance
« Reply #3 on: March 12, 2009, 01:07:15 PM »

Dan,

FLJ is right, as always.

But it might be worth knowing that the power difference might not be as great as the current differnce (or it could be more) :((
Reason:  the prop in the BT tube.  I confess to not knowing the blade section or twist but most marine props  - like aircraft props -  are mainly one-directional.  If you spin them t'other way at the same INPUT power you will get much less water pumped :}

For a bow thruster the terms forward and reverse have no real meanings, but connecting your ESc so that "forward" drove the bow thruster prop in the "backward" direction and VV.  you might find you had reasonably equal thrusts in both yaw directions.
Specialist bow-thruster props are completely symmetrical and reversible (have a look at Vetus BTs http://www.frenchmarine.com/ProductsC.aspx?CID=17  )
I would have thought that probably you only need a little reversible ESC for a bow thruster.  I believe that Action do things like this

andrew

ps after writing the above I have had a look at some model bowthrusters and see that the graupner one I found - the 1785 - is S400 powered and uses a paddle, not a propellor, and the Marx one has a symmetrical prop
Apologies for a not-very-relevant post, left in case it helps anyone making one of their own
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malcolmfrary

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Re: ESC Performance
« Reply #4 on: March 12, 2009, 02:07:04 PM »

If the bow thruster motor takes less than 20A, there is no problem.  Just because an ESC is capable of delivering a given number of amps does not mean that the motor will take them, and it is the battery and motor in this situation that decides the current.
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andygh

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Re: ESC Performance
« Reply #5 on: March 12, 2009, 10:05:03 PM »

I wouldn't use an ESC for a thruster anyway, much better with a switcher in my opinion
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andygh

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Re: ESC Performance
« Reply #6 on: March 13, 2009, 09:15:33 PM »

Fair point, good luck with it
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