Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: Billyruffian on January 08, 2008, 01:36:24 pm
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I have read a number of threads that refer to using fuses somehow.
I have a Viper 15 ESC and a 540 motor and have simply made the connections as per the instructions without using any fuses.
Have I done wrong and am I heading for a disaster.
Do I need a fuse and how and where do I put it.
Sorry if this sounds dumb - but I am when it comes to electrics.
Thanks for any help.
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Hi Billyruffian,
If you want to fit a fuse, then it goes in the positive supply from the battery. I suppose that a ten amp would be suitable.
With the Viper esc there is not a lot of point though. (Some will argue with that)
The Viper is designed to cut put if too much load is drawn, so wont burn out for that reason alone. The problem with an esc is that the controller will burn out quicker than a fuse will blow. Also the Viper esc is protected against motor short circuit so no problem there either.
The major problem with earlier msonic controllers was that they would keep going at maximum load until they got so hot they would catch fire. The latest generation cut out before they get that hot.
They were good in fast electric boats where we tend to water cool the controller as a matter of necessity.
When used in scale boats, they tend to be uncooled and work well. The trouble is that scale modelers tend to over load the motor with bigger props and long run times. The average for fast electrics is four to six minutes, where a scale boat can be on the pond for over an hour, with everything getting hotter and hotter. I have seen three scale models catch fire as a result of this on our club pond.
Bob
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A fuse in the main battery positive line is always a good idea as it can protect from accidental short circuits etc.
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For what it is, put one in..Easy to do and cheap so why not?
Barry
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Thanks all.
I will put one in just in case I think.
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Contact FLJ on the Forum he now owns Action who produce an excellent circuit board already fuse for around £20 thus is a fabulous piesce of kit and well worth the money, will also tidy up your wiring if necessary
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http://www.modelboatmayhem.co.uk/forum/index.php?topic=6201.0
Review of kit version by Wombat.
FLJ
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The fuse should be able to cope with the stalled motor, the ESC should be capable of handling rather more. This way the ESC limits the current allowed out to the motor to what is safe for itself. There have been cases where the ESC has an internal fault which passes almost limitless current within the ESC, bypassing the current limiting. Without a fuse in the power lead between the battery and ESC, a fire will result.
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I always play safe and put a main fuse in the positive battery line and another equating to the motor stall current between the ESC and the motor in case the prop gets jammed by weed or something else round it. Better safe than sorry and the cost is negligible.
Colin
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I always play safe and put a main fuse in the positive battery line and another equating to the motor stall current between the ESC and the motor in case the prop gets jammed by weed or something else round it. Better safe than sorry and the cost is negligible.
Colin
Snap!Seems such a logical idea that I always wonder why people ask me why I am "double-fused". Do it and save yourself a potential fortune!
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This is a brand new Viper ESC after its first outing WITHOUT fuses.
An internal short caused this.
Please fit a fuse.
Bob
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Hi guys....in my sun xx1 tug i run an mfa 400 on a gear box 2 to i reduction and an electronize esc.......i have caught weed on the prop a few times and every time the stalled motor has popped the 15 amp fuse very quickly.....No damage to the esc at all , so every boat i run now is fused O0
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Hi shipmate60,
Did you have a fuse fitted to the supply lead featured in the picture of your burnt out controller?
Bob
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BobF,
I stupidly relied on the internal Thermal Cut Out.
The ESC wast that hot it melted itself and badly scorched the upper deck.
No fuse fitted.
That is why I ALYAYS recommend fitting a fuse.
Bob
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Isn't it a pity that people can't be fitted with fuses - just think how much trouble would be avoided. ::) (On second thoughts, maybe circuit breakers would be a a better option - a tweak on the nose and they're up and running again as opposed to a minor operation)
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What are you on Colin ? :-\
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Sainsbury's 8 year old blended at the moment Richard....
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I want some of that Sainsburys stuff. It must be good.
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Can you get low voltage circuit breakers?
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Maplin do a range of self-resetting breakers from 1A to 10A. Look for AK07H on their web site. They will reset when the problem goes away. I believe Wingertaz does a 'Press to Reset' version - not sure about the ratings.
Barrie
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What fuse would you need to use on a 30A speed controller with a motor that stalls at 43A, and if possable would you advise somewhere I can get them.
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I know someone will argue with me but I use 15 or 20amp spade type car fuses [ the larger of the two ] and cut the positive wire and fix spade connectors to it. The car fuse is then pushed in the spade connectors. O0
You can get them all from Maplins.
Works for me.
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I know someone will argue with me but I use 15 or 20amp spade type car fuses [ the larger of the two ] and cut the positive wire and fix spade connectors to it. The car fuse is then pushed in the spade connectors. O0
You can get them all from Maplins.
Works for me.
Concur. Spades are quick,easy and cheap. USE THEM...or join the bankrupt club.
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What fuse would you need to use on a 30A speed controller with a motor that stalls at 43A, and if possable would you advise somewhere I can get them.
I would have looked for an ESC that could handle the stall current, but, having said that, if stuck with a 30A controller, I would check the current draw under load, hope it was considerably less than 30A, and, that being the case, use the highest value fuse under 30A. As others have said, use spade type connectors and blade type fuses, available most car accessory shops.
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I was alway of the understanding that the speed controller should be rated near the nominal operating current to give you better speed control. I.e. if the normat operating current of your motor is, say 5 Amps, then you should use a 10 or 15 Amp controller and fit a 10 or 15 Amp "slow blow" fuse to protect it..... is that still true of modern high freqency ESC?!?
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In the days of resistance controllers, a close match was essential. This is no longer the case with PWM ESCs. Generally, what will handle a lot, will handle a little. There will be some exceptions such as ESCs designed specifically for high performance where accurate low speed control is not a requirement, and a certain amount of coarseness can creep in.
A PWM ESC, by switching full-on and full-off, varies the proportion of full power offered to the motor, either by having a constant pulse rate and varying the length of time the pulse is "on" or having a set pulse length and varying the rate at which the pulses are generated. The motor is always offered the full power when the controller is "on", but if the controller is only "on" for 25% of the time, the motor gets 25% power, with speed to match. Provided the motor can handle the voltage, and the ESC can handle the current and stand up to the voltage, the same level of control is available over a wide range of motor and voltage with the same ESC.
Hope that makes sense.
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It's a completely different language isn't it ? :-\
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Just some more details on the speed controller, its a Electronize Type FR30 HX
Smooth P.W.M. forward and reverse speed control.
Selectable operating mode.
Low frequency mode: 100Hz
Variable frequency mode: 10 to 1000Hz
High frequency mode: 2000Hz
Low loss Power MOSFET current switching. (Only 2.7 milli-Ohms)
Low loss heavy duty cables. (0.25mm2)
High current automotive relays designed specifically for high power motor control.
Precision pre-set neutral.
Adjustable speed range to match throttle stick travel or scale speed.
6 to 24 volt motor battery operation. (5.5 volt min.)
30 amp. continuous load rating in either direction.
90 amp. short term stall rating. (continuous MOSFET rating)*
540 amp. peak rating.
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It's a completely different language isn't it ?
When you look at the innards, the phrase "I couldn't do that" springs to mind.
The modern controllers (i.e. electronic) are a LOT easier to set up and much better behaved than the stuff that went before. What downsides there are are easily worked round, usually by reading the instructions. Official fusing recommendations would be good, though. At the moment we are doing the practical thing of discussing the whys and wherefores, and hopefully a useful formula will appear sooner or later that will both work and be easy to follow for a beginner, especially one without an electrical background.
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I'll second that.