Model Boat Mayhem

Dry Dock / Shipyard: Builds & Questions => Any Other Builds => Topic started by: snoopy on July 09, 2006, 09:20:11 AM

Title: In-line Fuse
Post by: snoopy on July 09, 2006, 09:20:11 AM
New to modelling.  Forgive my ignorance. I have a 6v 4amp battery and am using a 540 motor and a marine 15 ESC. I want to put an in-line fuse in.  Where do I put it and what should the fuse rating be ? Does the in-line fuse go between he battery and the ESC ??
Title: Re: In-line Fuse
Post by: Peterm on July 09, 2006, 10:23:38 AM
Hi,  For my similar set-up I use a 10 Amp fuse fitted between the battery and the ESC.   The best type of fuse is the plug-in auto fuse.   Pete M
Title: Re: In-line Fuse
Post by: Malcolm Reade on July 09, 2006, 10:31:23 AM
Hi Snoopy

Fuses are protective devices. They are intended to protect a device that has a voltage applied to it.

The fuse rating needs to be lower than the maximum current rating of the connected device, but higher than the current drawn in normal use.

It would be pointless trying to protect an ESC rated at 15 Amps with a 25 Amp fuse - the ESC would be damaged before the fuse blew.? Pete is correct - if the current drawn by the circuit is less than 10 Amps.

The fuse needs to be positioned in the circuit where it will protect the intended device.

With DC circuits, the fuse will blow when the current passing through it rises sufficiently to melt the fuse media itself. ?The voltages normally used in model boats are not dangerous, but higher DC voltages are far more potentially dangerous than the equivalent AC voltage, simply because the current in the circuit continues to increase until the fuse blows.

Hope this helps.

Regards

Malc



Title: Re: In-line Fuse
Post by: snoopy on July 09, 2006, 11:09:11 AM
Hi Peter and malcolm, many thanks for your time and effort. I will now go ahead with that.  once again many thanks
Title: Re: In-line Fuse
Post by: quiksilva on July 09, 2006, 12:41:00 PM
New to boats but used to fly electrics (badly? :-\), Only thing i would add to the above is if you are using a speed controller with BEC (no rx battery required uses main power pack instead) you must ensure that any fusible link is between motor and controller not battery and controller as you will lose complete control.?
? ?Saw a guy maiden a powered glider with fuse between battery/ Speed controller using BEC which of course blew (sods law) and was amazed how easily a 1.8 metre kit fitted so easily into a black bin bag? ::)

Andy
Title: Re: In-line Fuse
Post by: Tug on July 09, 2006, 06:28:46 PM
Hi Snoopy,

I always fit the fuse between the motor and speed control,
  if you get a bu+++red speed control during the guarantee period they will usually change it,
not the same if you cut their wires or plugs off.
Title: Re: In-line Fuse
Post by: Ghost in the shell on July 09, 2006, 10:20:43 PM
also it may be a good idea to put a meter on the motor to see what your running load is first
Title: Re: In-line Fuse
Post by: BobF on July 10, 2006, 10:48:28 PM
Hi all,

With regards to the above topic.

If a fuse is fitted between the battery and the ELECTRONIC speed controller, would it protect the controller from reverse pollarity connection?

All my ESC,s protect themselves from overload, but not incorrect battery connection.

Bob
Title: Re: In-line Fuse
Post by: Tug on July 11, 2006, 10:13:52 AM
BobF, I would say a definate No! to that one

It would take some diode to stop say 100 Amps times two,
I would say it could be done but the added costs of diode's and bigger size of the heat sink would make the weight/size prohibative,
not to mention the power losses ( Doc, I said not to mention those)

Ken
Title: Re: In-line Fuse
Post by: BobF on July 12, 2006, 12:35:19 AM
Hi Tug,

Thanks for the info.
I thought that would be the case but I'm not really into electronics.

Bob
Title: Re: In-line Fuse
Post by: snoopy on July 26, 2006, 07:01:20 PM
Hi all
sorry for the delay, just back from hols.  Thanks to everybody for their time and effort in replying and the info.  Will certainly follow the advice.  many thanks.
Title: Re: In-line Fuse
Post by: A Model World on July 27, 2006, 08:56:25 AM
there is a gismo available that protects incorrect polarity on the esc's but without buying this a tip is to not only use different colours as we all do generally red black but also use different style plugs.
You would be amazed at the number I reckon it averages out to at least one person a day that does them back to front, though thats maybe not surprising considering is it some 60 people a day according to I think AA put petrol in diesel vehicles or vice versa
Title: Re: In-line Fuse
Post by: BobF on July 27, 2006, 03:20:56 PM
Petrol in a deisel tank? I've done that.  >:(
Title: Re: In-line Fuse
Post by: Tug on July 27, 2006, 05:46:39 PM
And on the basis of that Bob, fit one way plugs very soon,
is it Westbourne that do a set?