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Author Topic: Fuse requirements for Big Brushless?  (Read 6669 times)

inertia

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Re: Fuse requirements for Big Brushless?
« Reply #25 on: March 03, 2016, 01:43:52 PM »

This has probably been asked before, but where should the fuse go - between Battery and ESC or ESC and Motor?
Always between battery and ESC (by convention, in the positive wire). The other one is optional but has prevented damage on occasions.
DM
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sparkey

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Re: Fuse requirements for Big Brushless?
« Reply #26 on: March 03, 2016, 01:49:32 PM »

 :-)) Simples between battery and E.S.C. :-))
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Charlie

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Re: Fuse requirements for Big Brushless?
« Reply #27 on: March 03, 2016, 02:48:28 PM »

Thanks :-))

martno1fan

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Re: Fuse requirements for Big Brushless?
« Reply #28 on: March 03, 2016, 07:38:50 PM »

Ohh i dont know about that Dave people are always telling me i dont know what im talking about  :D lol .
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JimG

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Re: Fuse requirements for Big Brushless?
« Reply #29 on: March 03, 2016, 10:20:56 PM »

Always between battery and ESC (by convention, in the positive wire). The other one is optional but has prevented damage on occasions.
DM

If the esc has a BEC to provide power to the receiver this will lose power to the radio if the fuse blows.

Jim
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inertia

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Re: Fuse requirements for Big Brushless?
« Reply #30 on: March 03, 2016, 11:20:17 PM »

If the esc has a BEC to provide power to the receiver this will lose power to the radio if the fuse blows.
Jim

I may not have thought this through all the way (and it's well known that I am no fan of BEC), but if the motor has stopped then what advantage is there in having a working receiver? If the alternative is to have full control while the electrical installation burns then I know which I'd prefer.
DM

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martno1fan

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Re: Fuse requirements for Big Brushless?
« Reply #31 on: March 04, 2016, 08:15:27 AM »

Steve sent you a pm mate  :-)) .
Mart
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JimG

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Re: Fuse requirements for Big Brushless?
« Reply #32 on: March 04, 2016, 10:20:11 AM »

I may not have thought this through all the way (and it's well known that I am no fan of BEC), but if the motor has stopped then what advantage is there in having a working receiver? If the alternative is to have full control while the electrical installation burns then I know which I'd prefer.
DM
If you have  two motors then you can get the model back to shore. Also with most good modern esc designs there is overload and over temperature protection built in so the motor will cut leaving everything working and may restart when it cools down.
In 40 years modelboating I have never fitted a fuse to any of my models, fast electric and scale. In that time I have only had 1 esc failure in a fast electric where it overheated and melted the solder on the main board, lost the BEC with the motor at full power. The only case where having a fuse would have helped. Scale models I have had the prop weeded up completely stalling the motor without damaging the esc, all you need is to use the throttle stick and set to neutral when you see the boat stop moving.

Jim
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inertia

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Re: Fuse requirements for Big Brushless?
« Reply #33 on: March 04, 2016, 10:36:45 AM »

Jim
You didn't mention twin motors in your scenario - that's cheating!
As for the rest of your reply, much the same applies to you as does to Mart and my anonymous friend. If you understand and are very familiar with your equipment and you fit and operate it properly then there should be no need for fuses. Unfortunately from my experience as a manufacturer of model boat electronics I would say you are part of a vanishingly small minority.
Of course some folk fit a fuse because it makes them feel better about the safety of the model; I wouldn't argue with that either. It's not compulsory one way or the other.
(You know what's coming......)
Suit yourself.
Dave M
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malcolmfrary

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Re: Fuse requirements for Big Brushless?
« Reply #34 on: March 04, 2016, 11:00:22 AM »

A fuse between battery and ESC is generally a good idea.  It does protect the boat against any internal fault inside the ESC.  There have been recorded instances of ESCs having component failures that result in a short across the power supply.  Rare, but they can happen.  A fuse loses you control, but gives the chance of getting the boat back rather than watching it burn down to the waterline out there. 
A good friend, years ago, commented that "Any transistor will protect any fuse".  Power transistors were a bit delicate back then, and tended to go pop and disconnect.  More modern ones are more robust, and can melt to a short circuit.  Old time transistors could be their own fuse, modern ones might need a bit of help just in case something else fails and causes them to switch on (or not switch off) when they shouldn't.
In a fast boat where maximum power plus a bit for luck might be wanted, a judgement call is needed.  A fuse works because it is a bit of extra resistance in the wiring, do you want the extra weight, inherent fault liability of a deliberate weak link in the circuit and weight plus the fractional bit of extra resistance, or the perceived extra bit of performance? 
When a fuse blows, there is always the question of "Why".  Was it something that broke, was it something that was straying out of parameters, was it just the fuse or its mount getting old and tired?
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