" " " " help " " " "

[ICAUKdj]

Help ! ! ! ! ! ! how do I tune a tuneable electric type 540 motor??

Have got an multimeter to check amp draw and I am geting about a 2.40 to 2.60 amp draw peaking at 5.20 on start up, on a 7.2V 1800mAh battery on a straight thro concetion (no resistor) BUT blows a 10 & 15 amp fuze when in the water.

Is it high amp draw, listen to the revs, = max speed

(dont have a Rev counter)

or is it high revs, listen to the revs = high tourqe

"WHATS" wrong

"ANY" help would be great, and yes the Arrows in trouble again, no not the boat this time, its ME trying to set it up. PS took it out, see my other posting for how it went with trim tabs ! ! . . . ........... Steve

 

[scottie2212]

Hi Steve,

I'm assuming your stated current draw of 2.4 to 2.6 amps was measured 'on the bench' i.e. no load situation.

It is normal for an electric motor to draw more current when under load i.e. your boat is in the water. Current draw is affected by voltage, higher voltage = higher current and propellor size/pitch, larger prop and/or coarse pitch will increase load on motor and therefor draw more current.

If you've got a meter with a high emough rating test current draw when the boat is in the water - i usually do this in the bath.

Hope this helps,

Scottie

 

[bogstandard]

When using these tuneable motors you must remember that these were designed for model cars and had very little loading on the motor.

If used in model boats you should always go for a smaller prop size to relieve the motor loading to reduce the amperage, and keep the motor as fast as possible, which is its premium setting. This is why people put these motors onto a geared system (and a larger prop), rather than a straight drive.

Expect this motor, on a straight drive, to pull over 50 amps when loaded, and on an 1800mah battery expect runs of less than about 4 minutes.

You will need a speed controller to be able to take this sort of amperage, some of the car ones which use these hot motors can go as high as 200 amps (and nearly as many £'s)

You are delving into the realms of the bottomless wallet.