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Author Topic: esc  (Read 6637 times)

gary r uk

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esc
« on: April 08, 2007, 11:24:53 pm »

Guys
I have a repaired ESC back from the maker fitted all new fusees  new leads  all wirered up  smoke & flames looks like Scharnhorst gets to spend another week in dry dock.
oh bother
gary r
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Shipmate60

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Re: esc
« Reply #1 on: April 08, 2007, 11:38:13 pm »

Are you prepared to tell us WHICH esc?

Bob
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gary r uk

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Re: esc
« Reply #2 on: April 09, 2007, 07:48:20 am »

Hi shipmate60
Its a home made job from a electronic wizz from the club he makes all sorts of stuff esc amps mixers if it goes wrong give it back he repaires it he's cheep and local so no fuss draw back is he is now on holiday so Scharnhorst is to remain in dock.
The funny thing is after that esc went pop i then put a working Electronize in there and still nothing .
cheers
gary r
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Telstar

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Re: esc
« Reply #3 on: April 10, 2007, 11:27:20 am »

Hi Gary
It sounds as if you have a duff motor/s If the motor has developed a fault it could screw up any ESC you connect it to. I would try connecting a voltage source (battery) to the motor (one motor at a time) directly, with no ESC or radio equipment involved. Preferably use a voltage less than your normal battery voltage ( IE if you run on 12v try a 6v battery). Using temporary wiring connect the motor to the battery direct, and if you have the facility check the current each motor takes.
Out of water, with no load so to speak the current of each motor should be quite small ( I would expect less than 5A for any motor) however if the motor has been overheated or otherwise damaged the current can be quite large.
If your model got hot (I seem to remember some problem on a different post) also check that the wires to the motors have not melted to each other, where they are clipped up together passing through a bulkhead or such.
Hope you get going soon

Tom
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gary r uk

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Re: esc
« Reply #4 on: April 10, 2007, 01:20:53 pm »

Hi Telstar
I will try it with 6 volts i have done everything else you have suggested .
2 years to build a static model i would have made a better job Patience running out fast
cheers
gary r
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Shipmate60

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Re: esc
« Reply #5 on: April 10, 2007, 10:28:55 pm »

I have an old buggy mechanical speed controller that I use for a trials controller.
It will take huge currents, loads of misuse and costs about a tenner.
Your ESC hasnt taken out a channel in the reciever has it.
its worth checking everything a step ata time.

Bob
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gary r uk

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Re: esc
« Reply #6 on: April 10, 2007, 10:45:33 pm »

hi shipmate60
i have never heard of a channel going on a RX i will check that out as well
gary r
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gary r uk

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Re: esc
« Reply #7 on: April 11, 2007, 09:52:29 am »

Hi Shipmate60
I have just tried the motors on 6 volts under no load and my meter said 3.36 Volts .
RX ok.
Anyother suggestions apart from new motors.
Any idea why my other ESC which is known to work in another boat was not interested in the Scharnhorst but it works ok when back in the other boat.
cheers
gary r
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Shipmate60

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Re: esc
« Reply #8 on: April 11, 2007, 02:27:38 pm »

Gary,
have you tried loading the motors up.
Can be done BRIEFLY by holding the coupling or shaft.
Was the 3.36 Amps for both motors?

Bob
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gary r uk

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Re: esc
« Reply #9 on: April 11, 2007, 02:33:14 pm »

Shipmate60
the 3.36 volts was 1 motor with no load
gary r
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malcolmfrary

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Re: esc
« Reply #10 on: April 13, 2007, 11:45:40 am »

Is it 3.36 VOLTS or 3.36 AMPS?
A reading of 3.36 volts from a 6 volt battery with only an unloaded motor indicates a seriously goosed battery.
3.36 amps is not unreasonable, especially if both motors are drawing the same, or thereabouts.
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Tug-Kenny RIP

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Re: esc
« Reply #11 on: April 13, 2007, 01:09:54 pm »


Does anyone know what voltages come OUT of the Rx, or perhaps signal waveforms.

My reason for asking is that this goes to the ESC, and I was considering building my own speed controller.



Cheers...Ken
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wombat

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Re: esc
« Reply #12 on: April 13, 2007, 01:25:23 pm »

Hi Kenny,

not checked on a scope, but IIUC the rail voltage for the RX is typically 5V. The servo signal is a TTL squarewave, with the high portion between 1mS and 2mS in width, with 1mS representing one extreme of travel and 2mS representing the other.  (Or is it 1mS mid scale and 500uS for lower limit)......

But anyways you can use an integrator to turn the pulse width into a DC voltage which you can then use to drive a PWM. International Rectifier do some nice FETs and things for the output.

Wom
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gary r uk

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Re: esc
« Reply #13 on: April 13, 2007, 04:25:26 pm »

Hi Guys
Well after a long week of what the f^%k is going on here it has been sorted,don't know why or how buy now that i have put a separate battery powering the RX it works like it says on the tin.
Separate power for the RX was not done on the previous set up and it worked OK.
Anyway all done many thanks for all your help Scharnhorst is now the most checked out battleship electrically speaking on the planet.
cheers
gary r
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malcolmfrary

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Re: esc
« Reply #14 on: April 14, 2007, 10:30:34 pm »

Hi Wombat
The TTL standard gives a lot of scope to manufacturers to create confusion.  A logical "1" should be half line voltage, or greater, a logical "0" is 1 volt or less.  Some receivers put out line voltage and ground, some half line and ground.  If the device being driven, servo, ESC, switcher or whatever requires the full RX line voltage as a logical "1", then problems can occur if used with an RX that only puts out a 2.5 volt "1".
Having done a component count on a few likely circuits I came to the conclusion that its actually cheaper, as well as more compact, to buy ready-made.  The only time I don't now is when I do a small one, when I butcher a servo.  This gives an ESC and a motor in one go.  The limits are a very narrow deadband, and a max of 6 volts supply and a motor that doesn't draw more than 500mA.
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wombat

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Re: esc
« Reply #15 on: April 15, 2007, 08:35:08 am »

Hi Malcolm,

Actually, I would say that the use of a TTL output, which appears to be the standard choice is a pretty well established standard used by the majority of logic chips and ASICs.  The critical parameters for TTL are VIH and VIL - the minimum voltage than an input will recognise as Logic 1 (VIH) and the maximum voltage that an input will recognise as a logic 0. For standard TTL, these are 2V and 0.8V respectively. These levels will be met IIRC also by 3.3V CMOS outputs.  There may be problems if you try to drive pure CMOS devices such as 74HC or similar families with some outputs because VIH and VIL are significantly different, but there are ways around this - usually a pull-up resistor on the driving output is enough. 

It may be cheaper to buy in an ESC, but less fun if you fancy that as a project, or if you require something a little bit special.

Wom
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FullLeatherJacket

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Re: esc
« Reply #16 on: April 15, 2007, 10:07:24 am »

I remember a guy at University who sat patiently through half an hour of a lecture on Vectors and then said "Excuse me, but I'm afraid you've lost me a bit". Not wishing to appear unsympathetic, the Prof said "How far back would you like me to go, John?"
"Well," says our hero, "if you start with "Good morning" I'll take it from there". I know now how he must have felt.
I eagerly await the English translation of this thread.......or maybe a DVD........
Come back to Planet Earth, boys - we might need you again! ;)
FLJ
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OMK

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Re: esc
« Reply #17 on: April 15, 2007, 12:36:41 pm »

Oh you ignoramous! This is the first half-decent techo-babble we've had in ages! Enjoy, I say!!
TTL... narrowband... deadband... micro-second pulses...
Bliss! You're only jell-us because you don't know the difference 'tween a 74 series and a 74HC series. Man!!
(What's a vector, anyway?)

You're right, Wom... it is 1.5mS pulse for neutral. Unless, of course, it's a Futaba. The crafty buggers upped the lefmost servo position from the usual 1mS to 1.12mS.

Dave, me ol' mate. TTL? Depends which side you're batting. Could be Transistor Transisor Logic, or Total Total Logic.
See?... fascinating, innit?
Fee for this folly?... Nah, on the house. Nay, better still -- your message didn't reach my hotmail address. Try again.
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anmo

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Re: esc
« Reply #18 on: April 15, 2007, 01:13:33 pm »


(What's a vector, anyway?)


I've got one of those. It's parked outside, has four wheels, and was made in Sweden.
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OMK

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Re: esc
« Reply #19 on: April 15, 2007, 04:27:43 pm »

Oh, my mate drives one of those! Or was it a Vauxhall Victor?

Hey, gary r uk... when your ESC went belly-up... did you enjoy that looooong, cooooool, succulent whiff of burnt wire insulation? That's the good thing about home-brew gadgets... you gets to enjoy little moments like that.
But you're breaking my heart, Sir. I hate to see a man in dry dock. Even if his grammar IS up the shoot.
Would this be of any help to you?.....
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John W E

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Re: esc
« Reply #20 on: April 15, 2007, 04:45:22 pm »

pmk my son, do you get a free lighter and packet and Golden Virginia free with the speed controller  ;D

Anmo just had to get rid of my Swedish car, but bought another one - different model though, and different Company  ;D they make marine diesel engines ::)

aye
john e
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gary r uk

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Re: esc
« Reply #21 on: April 15, 2007, 05:24:03 pm »

Hi PMK
It would if i knew what it was??.
Scharnhorst went back to sea today and was fine a little under powered by the new MFA480's but thats OK.
Yes the smell of burning insulation takes a while to go.
cheers
gary r
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FullLeatherJacket

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Re: esc
« Reply #22 on: April 15, 2007, 05:37:54 pm »

Oh you ignoramous! This is the first half-decent techo-babble we've had in ages! Enjoy, I say!!
TTL... narrowband... deadband... micro-second pulses...
Bliss! You're only jell-us because you don't know the difference 'tween a 74 series and a 74HC series. Man!!
(What's a vector, anyway?)

You're right, Wom... it is 1.5mS pulse for neutral. Unless, of course, it's a Futaba. The crafty buggers upped the lefmost servo position from the usual 1mS to 1.12mS.

Dave, me ol' mate. TTL? Depends which side you're batting. Could be Transistor Transisor Logic, or Total Total Logic.
See?... fascinating, innit?

B100dy hippies........... >:(
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OMK

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Re: esc
« Reply #23 on: April 15, 2007, 07:56:56 pm »

Hippy?

Hehee!

Gary r, old chip, since you don't know what it is...
And Bluebird... Now because you're so eagle-eyed, the aforementioned ESC, lighter AND waccy-baccy is all yourn if you can tell me what THIS is.
Is it...

A) Six Geordies flat-linging after a typical Saturday night? Or...
B) The most cleanest output wave-form of any ESC you've ever seen? Or...
C) Same as A, but photo taken while said ESC is being subjected to just about all the unwanted interference you could chuck at it, while still retaining that usually elusive and super-clean signal purity so beloved by the modelling fraternity throughout the lands?

Your answer, please, on the reverse of a blank cheque, posted direct.
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John W E

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Re: esc
« Reply #24 on: April 15, 2007, 08:05:13 pm »

Hi there PMK my son - its obviously an oscilloscope  ;D and I think the signal on the screen represents the pulse from a Futaba receiver to a thingamajig an ESC or a switcher  :-\ timing cycle.

~Cant be 6 Geordies flat-linging my mate, I dont think 6 Geordies would stay friends lang enough - at least not on this forum

ah, can I phone a friend, or ask the audience

aye ya fathor thinks its C son - the answer is C  ::) ::) ::)   got no friends left to ask  ;D ;D


aye
john e
bluebird
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