Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: daveorgan on December 03, 2011, 08:15:32 pm

Title: inline fuse
Post by: daveorgan on December 03, 2011, 08:15:32 pm
will it hurt to put a inline fuse inbetween battery and speed controller aswell as having one between speed controller and motor

ive been told if i have a fuse between battery and speed controller and for some reason it blows it can damage speed controller is this true ?

regards
dave
Title: Re: inline fuse
Post by: Subculture on December 03, 2011, 08:19:15 pm
I can't think of any valid reason why it should. I never fuse between the motor and ESC though, just between battery and ESC.
Title: Re: inline fuse
Post by: RaaArtyGunner on December 03, 2011, 09:28:20 pm
I can't think of any valid reason why it should. I never fuse between the motor and ESC though, just between battery and ESC.

Not being a "Black artist", wouldn't the ESC be damaged, if the motor pulled more, than the ESC rating.

For instance, motor draws 15 amps, while ESC is 10 amps and 10 amp fuse between ESC and battery, ESC would be "dead/dying" before fuse acts, as it is after the ESC, or have I missed something.


No wonder its "Black Art"
Title: Re: inline fuse
Post by: john s 2 on December 03, 2011, 09:36:45 pm
Mtronics are supposed to have overload protection. Rated at a high level. A fuse can only fail if the current being drawn is more than its rating. A fuse will fail more quickly the greater the current drawn.What are known as quick blow fuses can be brought. It does seem in Daves case that the esc was not despite failure, drawing enough to blow the fuse.John
Title: Re: inline fuse
Post by: dem555 on December 04, 2011, 02:37:48 am
Remember, a fuse can only protect the circuit after it.
Anything before it has no protection.
You are aiming to protect the wiring as much as the connected components.
It will do that job very well if correctly sized and rated.
It is an essential component of your model.
As in real life - such as in your house - fuse as near the supply as you can.
In a model boat that's the battery.
Therefore, if you fuse nearest the battery, anything after the fuse, no matter what, can only draw up to the maximum rated current of the fuse, or else it will pop.
There's no harm in adding additional fuses wherever, depending on your setup.
i.e. if you have 2 motors fed from 2 ESC, use 2 fuses, 1 in each leg from battery to ESC.
So, it would also be wise to individually fuse any installed devices, eg., bow thruster, sound/ smoke unit, etc.,
Or wherever you drop cable size, as in lighting.
Again as per real life.
Needless to say, all cabling and connections must be able to carry the normal running currents easily.
Unfortunately, in models, getting the fusing parameters correct is not so simple as in mains supply equipment.
Title: Re: inline fuse
Post by: RaaArtyGunner on December 04, 2011, 07:37:28 am
Remember, a fuse can only protect the circuit after it.
Anything before it has no protection.
You are aiming to protect the wiring as much as the connected components.
It will do that job very well if correctly sized and rated.
It is an essential component of your model.
As in real life - such as in your house - fuse as near the supply as you can.
In a model boat that's the battery.
Therefore, if you fuse nearest the battery, anything after the fuse, no matter what, can only draw up to the maximum rated current of the fuse, or else it will pop.
There's no harm in adding additional fuses wherever, depending on your setup.
i.e. if you have 2 motors fed from 2 ESC, use 2 fuses, 1 in each leg from battery to ESC.
So, it would also be wise to individually fuse any installed devices, eg., bow thruster, sound/ smoke unit, etc.,
Or wherever you drop cable size, as in lighting.
Again as per real life.
Needless to say, all cabling and connections must be able to carry the normal running currents easily.
Unfortunately, in models, getting the fusing parameters correct is not so simple as in mains supply equipment.


OK I get it now. Thank you.

Had it all back to front, was thinking the flow was from the ESC to the battery, when it is from battery to ESC etc.

Simple eh?  O0 O0 :-)) :-))
Title: Re: inline fuse
Post by: john s 2 on December 04, 2011, 04:19:13 pm
In a way your correct. Electricity does have a flow and return of course. But its correct practise to cut the supply not the return. Doing it this way ensures nothing is still live to touch in the advent of fuse failure.John.