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Author Topic: Fused or not?  (Read 2168 times)

tomocj

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Fused or not?
« on: January 26, 2009, 01:32:16 PM »

Do you need to include a inline fise between battery and speed controller?

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Martin [Admin]

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Re: Fused or not?
« Reply #1 on: January 26, 2009, 01:47:32 PM »

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Peterm

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Re: Fused or not?
« Reply #2 on: January 26, 2009, 01:49:46 PM »

Martin is bang on!   Pete M
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FullLeatherJacket

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Re: Fused or not?
« Reply #3 on: January 26, 2009, 01:51:39 PM »

Do you need to include a inline fise between battery and speed controller?

Only if you're inordinately fond of buying speed controllers, in which case I know just  the place..................... ok2
(Fusses or fise - it doesn't matter which!)

FLJ
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Martin [Admin]

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Re: Fused or not?
« Reply #4 on: January 26, 2009, 01:57:50 PM »

Martin is bang on!   Pete M

I've peaked too early, it's only January and I've used up my years quoter of correct answers!  {:-{
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Shipmate60

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Re: Fused or not?
« Reply #5 on: January 26, 2009, 04:23:30 PM »

This Speed Controller had thermal protection but NO FUSE.

Your Choice!!

Bob
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amdaylight

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Re: Fused or not?
« Reply #6 on: January 26, 2009, 04:37:04 PM »

Martin is bang on!   Pete M

I've peaked too early, it's only January and I've used up my years quoter of correct answers!  {:-{


Martin,

We won't tell any one, so in June or July you can give another right answer and every one will have forgot this one.  ;D  :}

Andre
over yonder in Portland Oregon
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tomocj

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Re: Fused or not?
« Reply #7 on: January 26, 2009, 05:08:16 PM »

thanks for that and after that pic of shipmate60 fuses it is then.
A further question why do aero modelers not use fuses?chris

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Mankster

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Re: Fused or not?
« Reply #8 on: January 26, 2009, 05:35:26 PM »

thanks for that and after that pic of shipmate60 fuses it is then.
A further question why do aero modelers not use fuses?chris



Because a hot ESC is cheaper than a lost plane, lots of submariner dont uses fuses for the same reason.

malcolmfrary

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Re: Fused or not?
« Reply #9 on: January 26, 2009, 06:42:19 PM »

Usually, an ESC should be chosen to carry about twice the maximum running current of the motor.  Any protection in the ESC will be happy with whatever the motor tries to do at it.  The fuse between the battery and ESC protects the battery and the wiring to the ESC from problems within the ESC, and should be rated somewhere between the motor max and the ESC rating. 
The motor is liable to stall in a boat if it finds weed - this is unlikely on a plane.  A plane ESC will not usually need reverse, and its a fault in the reversing circuit that incinerates ESCs like the one above by putting a short across the power supply.
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Shipmate60

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Re: Fused or not?
« Reply #10 on: January 26, 2009, 08:52:58 PM »

Malcolm,
That particular ESC had an internal short caused by poor insulation which broke down under load.
It was a known fault in a small number and immediately exchanged.
Didn't help the deck above on my model as the heat burnt right through it.

Bob
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malcolmfrary

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Re: Fused or not?
« Reply #11 on: January 27, 2009, 11:15:47 AM »

Yes Shipmate,
The non-relay ESCs have a bridge of four transistors to drive the motor arranged like a "H", with a transistor in each arm and the motor in the crosspiece.  These work in two pairs, top left and bottom right for forward, top right and bottom left for reverse.  If any one of these is either shorted or caused to remain switched on, then when the other pair switches on, there is a direct short across the power line, with a consequent enormous current and heat dissipation.  Even with a fuse, there is the possibility that a fault could occur that would result in a massive power dissipation in the ESC because mother nature makes strange and unlikely circuits, but a fuse covers most eventualities.
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