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[stallspeed]

Stallspeed. speaking in riddles does not make much impression on our underdeveloped, ignorant minds.

If you can't express yourself clearly then there isn't much point in posting.

OK,the current drawn was no more than normal.
The overheating was because the three legged current carrying components are not mere switches.They are transistors.
The name transistors is short for trans-resistors because they pass through a resistive region when going from insulators to current conductors.

They are supposed to be controlled by applying either 0 volts or 4-15 volts to their control pin called a gate,to switch motor current off and on
In between 0 and 4 volts they are are poor conductors (resistors) and get hot to destruction because the controller permits the applied gate voltages to linger in the danger zone.

[DickyD]

Very clear, didn't understand a word. Probably because I am not an electronics nerd. 

[Timo2]

     HA  

They are supposed to be controlled by applying either 0 volts or 4-15 volts to their control pin called a gate,to switch motor current off and on
In between 0 and 4 volts they are are poor conductors (resistors) and get hot to destruction because the controller permits the applied gate voltages to linger in the danger zone.



   Cost me    a rebuild to a ESC unit 12v with 6V bec  input volt dropped below 9V bec cutting out magic little black bits went bang.- hot & smoky.     not good cost me more money  ( had a ticking off buy   the man in the shed )

   YES low Volt cost Money
 
    Timo2

[andygh]

Well I get it and I'm not a nerd of any kind 

[DickyD]

Working Voltage :   5-10 cells, 6-12v, NiCd, Nimh Li-po battery
BEC Current :   5v/1A
Low Battery Cutoff :   5v
Continuous Output Current :   110A forward, 40A backward
Reversion :   Yes
Low-Voltage, Cut Electricity Protection :   Yes
Dimension :    54.8 x 40 x 14.7mm
Weight :   59g
Package Weight :    ~84g

OK Andy explain to me in laymans terms, if it has  Low Battery Cutoff :   5v and the spec says Low-Voltage, Cut Electricity Protection :   Yes and it is designed for  Working Voltage :   5-10 cells, 6-12v, NiCd, Nimh Li-po battery

Why did the speed controller melt down ?

[andygh]

Don't know about any of that  I was just saying I understood Stallspeeds post

[DickyD]

Sorry thought you knew thats what he was on about.

[wombat]

Hi Lee,

Well, proferring my own opinion here.....

Looking at the spec for the ESC - 110A/40A - yeah, right. Instanteneous current maybe - for continuous use with those heatsinks maybe a fifth or a tenth of that.

Low voltage - I think that it is unlikely with a 6V VRLA. Low battery cutoff at 5V - this is for the LiPO batteries - if the incoming power drops below 5V the system shuts the output off to prevent overdischarging the LiPO and damaging it (with potentially catastrophic results).

Low gate voltage on the drive FETs can cause them to overheat - becaue the channel resistance is high, but I suspect the cause of the meltdown is not this.

Looking at the construction of the thing, I suspect one of two things has happened - possibly water has got onto the PCB - the resistance of this can be low enough to start the drive transistors to conduct so they are always on. This can then cause an overheat. THe other possibility is that the metal tabs on the FETs have shorted to each other either because they have been bent wrongly or the insulation has not be installed properly.

Remember you get what you pay for!

Wom

[Shipmate60]

Wom,
Thanks for that.
To say I was getting confused is an understatement.
The Main Drive battery is a 6 volt Gell Cell and I couldn't see  the voltage dropping down to 5 volts after less than 200 metres.
From the enclosed pic I couldnt understand where the high current came from to allow the burn out as the wiring looks intact and the heat source is FROM the ESC.

Bit like a brand new one of mine some years ago.

Bob

[wombat]

Hi Shipmate60,

That looks like a very melted MTroniks ESC - I would guess given the nature of the encapsulation on those puppies that it is an internal fault - not enough to turn the transistors on fully, but enough to get them very hot - once the junction gets above about 170C all hell breaks loose.

The thing with PWM ESCs like this, the transistor is either on or off - these cases are the points where the FETs dissipate minimum power - the heatsinking is designed for this condition. As soon as you get one or more of the FETs partially turned on the power dissipated in the ESC increases rapidly - though this is still relatively small compared to the overall power of the system.
With a bidrectional ESC, if any one of the transistors is partially turned on becaue of a fault the ESC will continuously draw current and this will convert to heat - and that will result in a meltdoown

Wom

[malcolmfrary]

Its also very possible that if the ESC was enclosed in a close fitting box, there was no cooling airflow.  If it was working at near its real maximum rather than that suggested by the sales blurb it passed the limit and died.  If a transistor, having been well cooked, fails to switch off, when reverse is engaged, you have a short across the power leads and instant doom for everything inside.

[ajb68]

Firstly hi to all , ive had a break from the hobby for a couple of years but back now 
I had a M TRONIXS  esc that did the very same thing and i phoned them and told them what had happend and as i bought it direct from them and they couldnt see any cause as a result of the motor i installed they replaced the esc no problem , i am not sure where your esc was bought from but i tend to buy from model shops or direct i just think its safer that way rather dealing with somebody who maybe wont care cos he has got his money , im not saying this is the case but just my point of view ,, good luck and i hope you get going soon , Andy

[Wasyl]

Having read whats gone on over these two pages,Ooooo,I hope i never have anything like this happen to me,it looks ever so complicated,thats why i,ve gone for over kill,i.e.fuses covering fuses,

Wullie

[Shipmate60]

malcolmfrary,
There was plenty of air circulation around the ESC as what is shown is the board which sat under the superstructure.
When it melted it burnt a hole through the thin wooden deck some 2-3 inches above it.

Bob

[malcolmfrary]

malcolmfrary,
There was plenty of air circulation around the ESC as what is shown is the board which sat under the superstructure.
When it melted it burnt a hole through the thin wooden deck some 2-3 inches above it.

Bob

While this may well be true of the picture that you refer to, I was commenting on the subject of the original post, where mention was made of the probability of restricted airflow for cooling.

[peter.dwight]

Greetings.
Re your spectacular melt down.
You didn't by chance connect it the wrong way round on a previous occasion. It may be that the reversed voltage on the components may have affected their performance, so when it was put in to service the damage was already done?
Just a thought, as modern electronics are very votage sensitive and we have no idea of what components are buried away inside those heatsinks.
Yield not to dispair, you just keep paying the money and you will have success.
Regards.
Peter.

[andygh]

Just to stick my oar in again. I blew one of these apart a couple of weeks ago WITH a 20A fuse fitted, battery voltage was good etc.
My prop caught a submerged pollybag and WHAMMO, 8 quid up in copious amounts of very smelly smoke. I reckon the current rating of 100A isn't just optimistic it's on cloud 9

[pompebled]

Hi guys,

I'm running this ESC in my tug ( http://www.modelboatmayhem.co.uk/forum/index.php?topic=19477.0 ) and the motor powering it is just a 380.

After I came home from a run around our city (an hour and a half full throttle), the ESC was still warm, when I opened the hull after walking home from the waterfront.

I imagine this motor is just about the limit, this ESC can handle for a longer period of time (running on 7,4V).

I hope, the topicstarter didn't wire the motor the wrong way, and ran the ESC in reverse in order to go forward, as the ESC only has two transistors for reverse versus three for forward.

Reading all this mayhem on this cheap ESC, I think I'll add a small fan for the long hauls...

Regards, Jan.

[stallspeed]

Jan,the component you mistake for an extra transistor is actually the bec regulator.

[pompebled]

My mistake, I haven't taken the ESC far enough apart to be able to read what's on the 'black thingies'..., I only wanted to be sure the transistors had physical contact with the heatsink.

I guess it would have to be three transistors for forward and just one for reverse than, to reach the big difference between 110A and 40A.

Maybe, if I have absolutely nothing to do, I may take the ESC apart and trace the wiring to sketch its layout.

Regards, Jan.

[stallspeed]

No need!
There are plenty burnt out ones for that.

[pompeyone]

i had finally got my little bait boat all ready, all new receiver gear and esc, new Yuasa 6v 12ah battery's new hand set.
so set out to my local lake to break a bottle of champers on her hull and give her the first outing....

all was going well on the way out to about 170metres and then on the return trip she just stopped :-(
fortunately i had tied a fishing line to her as it was the first trip so was able to bring her in, but when i had a look inside the esc had melted!!!

the original post on what i was putting in her is found here: http://www.modelboatmayhem.co.uk/forum/index.php?topic=16475.0

so what i am asking is why? is it because;

A; it was the wrong esc?

B; it was because i stupidly put the esc back into the fairly tight electronics housing which the original radio gear etc was in? therefore pretty much covering the heat syncs :-(

C; i did not have any cooling going to the heat syncs ie; water cooling?

D; a combination of the above?

i could do really with getting her back up and running asap, so can anyone shed any light on this and/or recommend a replacement esc and some cooling?

all the info i have on the boat is on the original thread.

thanks very much in advance

a very disheartened Lee

hello lee,i have got ELmodel 110amp esc,from hongkong,also mine worked for five minutes then melted,since then i have fitted 20amp viper and had no problems ,so i think its down to 110amp esc crap.i have emailed suppler but had no replys.

[FullLeatherJacket]

Remember you get what you pay for!
Wom

Sometimes you don't even get that  much, but the maxim holds true with these things. Eight quid for a speed controller, including P&P from halfway round the world, beggars belief. We used to call it "dumping" when a country sold off bulk stocks of unwanted goods at silly prices on the world market. It rather looks like the folk who part with their money for these items stand a good chance of getting dumped on.............

And before we get the usual "I've got one and mine  works fine" postings - all very helpful and well-meaning, I'm sure - then I must say that we have perhaps 20+ customers who weren't as fortunate with their examples. As for that 110A continuous rating, who are they kidding? Maybe Chinese amps are smaller than UK ones?

FLJ

[andygh]

You are of course 100% correct Mr FLJ BUT I have lately bought my esc's from your good self (and perfect they are too) but you don't make one for the current/voltage rating I need, I have the choice of buying a 60A esc for around £60  or trying one of these Chinese jobbies for £8, I didn't expect much but decided it was worth a gamble, OK it didn't pay off, hey ho never mind. To paraphrase a very wise man I pleased myself  Lesson well and truly learned, back to the drawing board
PS. I have purchased several other items from the same source in China and I have been happy with all of them 

[FullLeatherJacket]

you don't make one for the current/voltage rating I need, I have the choice of buying a 60A esc for around £60  or trying one of these Chinese jobbies for £8, I didn't expect much but decided it was worth a gamble, OK it didn't pay off, hey ho never mind.

Andy

My posting wasn't a sales ploy, mate. If you really do need something which works at >30v and/or 30A then yes, we don't make one. Looks like goodbye to sixty quid, doesn't it? I'd rather recommend a competitor's products which I know will work reliably than something which will likely not live up to expectations and be unrepairable as/if/when it goes bang. Having bought one of these and then have it go wrong is galling for you, but I see a lot more instances from this side of the counter. You have been around a few model boats and you therefore should know what you're doing/looking for; there are far more who don't.

I must get a couple of phone calls every week from people who've either taken a leap of faith like you and Lee both did or - worse - been flogged something off a shop shelf by an assistant or proprietor who neither knew nor cared about what was the right item for the job. Have you heard the one about the 15-turn stock 540 sold with a 60mm 4 blade prop and a 15A speed controller to run in a 32" tug on 12 volts? No? How about a pair of Speed 700BB Turbo 9.6v motors and X45 racing props for a 1/96 Fleetscale battleship? Believe; I've had both victims on the phone in the last seven days. It grieves me to listen to these stories and I wonder how some traders sleep at night, but human nature being what it is then these sob stories will keep on cropping up.

I don't normally like criticising other folks' stuff but these particular Chinese-built ESCs really seem to be a liability - you should hear what our Aussie agent says about them (no - maybe you shouldn't!!). My message to anyone who is contemplating buying one is to think twice. There are two Mayhemmers here who won't do the same again and many other people who would agree.

Suit yourself, but caveat emptor and all that jazz.

FLJ