Mtronic sub4 ESC question - Mtronic sub4 ESC question

[turbobearcat]

Ok I have a question with a possible problem.

While testing the electronics on the converted Revell UBOAT, I turned off the radio to see how things would respond, man was a suprised! I seen the motor hit full speed and a hard to right rudder control!!! I'm scratching my head to why this is happening, none of my ships act this way but none are using this type of ESC or FM radio either.. So I need to know what can I do to correct this issue? Any ideas folks.. I want this baby to be ready soon.


Mark

[joeangi]

I too have this problem

I too have this problem with an Msonic speed controller, Motors jumping...stop full speed, reverse, servos running lock to lock....but I tried an LRP f1 and a novak with the same response you are having. I tried 3 receivers as well...fianlly just bought a PCM receiver.

Make sure you have 3 capacitors on your motor (s?)...try separating parts on the bench to attempt to find what is giving off the noise..


Good luck...my PCM has not arrived yet. I will let you know how that works.

[rcher]

There is no problem here.

There is no problem here. That is normal behavior for a radio system. Which is why you alway turn the transmitter on first then the reciever and turn off the receiver and the transmitter last.

Do you have a failsafe installed? What a failsafe does is sets your servos/ESC to a pre-set position in the event of a loss of radio signal. Else you can get a PCM radio with built in programmable failsafes.

[ramius-ii]

Hi Mark]http://www.subcommittee.com/forum/icon_question.gif If this is

Hi Mark]http://www.subcommittee.com/forum/icon_question.gif[/img] If this is correct, then something is producing a signal to the two devices. I would first check the batteries or what you are using to supply power to the receiver. Low receiver power can provide many "spritual" results. If you are using a battery eliminator /BEVR this can cause problems if not correctly built or if there is a component failure. Just as an FYI, the ESC and servo going to a full position, usually indicates they are receiving a 2 ms command signal. The question is, what is generating the signal.

Best, Ed

[joeangi]

I hate to disagree...but a

I hate to disagree...but a speed controller should not do anything but go to stop if it loses signal. I understand that we should not be turning off the transmitter before the receiver...but we are attempting to simulate loss of signal. If we lost signal and the boat goes to full throttle and the servos are jumping back and forth...we will never find the boat...until Dr Dave gets his sonar working.

I do agree that there is a signal being generated that is causing the electronics to jump....but narrowing it down is the problem.

[rcher]

You are probably right about

You are probably right about the speed controller. I checked and my ESCs (Castles, etc) are designed to shut down if there is a lost of signal. However Ramius may be closer to the truth. I have seen older speed controls go into full speed and the servos go full lockout when the batteries get low. I've seen my airplanes go into the death spiral from low batteries as well. You might try using a separate receiver battery and disconnecting the BEC.

Mark, Unplug your motor from the ESC and see if it happens again. Then try plugging another servo into the ESC receiver channel and see what happens.

[ramius-ii]

Hi Joeangi]http://www.subcommittee.com/forum/icon_wink.gif I was simply

Hi Joeangi]http://www.subcommittee.com/forum/icon_wink.gif[/img] I was simply providing a starting point that I've found to be common to this type of problem coupled with the reports on other posts of this nature to start the narrowing down process.

Best, Ed

[joeangi]

Dear Ed,

I agree with your

Dear Ed,

I agree with your conclusions....I am still chasing the same gremlins thought. I have taken the bec out of the equation by running a 4cell alkaline pack direct to rx and pulling the red (power) wire out of the plug from esc to rx.

The apc 3 was really driving things nuts...but there is a cap and a diode on the circuit which is supposed to eliminate this problem. I replaced the diode....same problem. Finally I ran the apc as stand alone so it was not hooked to rx....still having problems....it has to be my ballast tank switch, even thought it has been replaced by Norbert.

JR sent me a new pcm rx last night, but I have not had the time to put it in. I think for persistant problems such as this, it could be the easiest answer.

Joe

[turbobearcat]

Hi Mark]http://www.subcommittee.com/forum/icon_question.gif If this is

Hi Mark]http://www.subcommittee.com/forum/icon_question.gif[/img] If this is correct, then something is producing a signal to the two devices. I would first check the batteries or what you are using to supply power to the receiver. Low receiver power can provide many "spritual" results. If you are using a battery eliminator /BEVR this can cause problems if not correctly built or if there is a component failure. Just as an FYI, the ESC and servo going to a full position, usually indicates they are receiving a 2 ms command signal. The question is, what is generating the signal.

Best, Ed

yes I get this but turning off the transmitter just to see what would happen if the reciever would lose the signal.

I checked one thing, the motor only has 1 cap on it, and I'm not sure of the size but I will run out to Radio shack and grab some 1uF caps.. and I hope this resolves the problem.

I don't have a failsafe installed, which in a sub it should be installed
unlike one of my surface ships it's easy to recover.

Speaking of my newest warship HMS HOOD is a excelllant ship for rough water I found out, handling waves that swapped my Musashi and yet no water was inside the Hood..

I changed the Musashi's weight around since I'm trying out a new battery system, I added too much weight to the front of the boat which resulted in it driviing alittle too hard into the waves..and believe me the waves were nearly 1 foot tall!

Now the Wallyworld sub..it seems to live for the moment and can operate very close to shore without fearing if being driven under like Tyler's Destroyer which came too close to shore..OUCH!

I'm stating to think that Subs are going to be my main stay and my ships will be retired as they wear out and become models to gawk at.

Mark

[ramius-ii]

Hi Joe and Mark]http://www.subcommittee.com/forum/icon_wink.gif

Just

Hi Joe and Mark]http://www.subcommittee.com/forum/icon_wink.gif[/img]

Just as an FYI, capacitors with a value of less than 1 mfd are considered non-polarized. That is, they do not have a + and -. Capacitors of 1 mfd and above ARE polarized and only want to see + on the + lead and – on the – lead. If you reverse polarize a polarized cap, you run the risk of having a small “fire cracker” go off inside your sub. Some caps (like tantalum) will act as a diode and thus produce what looks like a short to some circuits.

About the only place for a polarized cap would be on the power and ground wire of a servo to assist in reducing servo twitch or nervous servo. This occurs when using a servo with small wires and the initial current requirements of the servo are higher than the wires can support. The capacitor value is generally greater than 10 mfd.

Hope all this helps, Best Ed

[turbobearcat]

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[color=#0000FF]]

[Guest]

I'm not precisely sure why

I'm not precisely sure why you are getting the problems you are, however try another servo in it's place, and see if the problem remains.

Also I don't readily recommend PCM radio for submarines, for the following reason- they have built in safety controls that trigger instantaneously on the loss of signal.

What's the problem with that you may ask?

Well although failsafes are a good and essential thing in a sub, you do want some kind of time delay, i.e. 2 seconds or more before it triggers, to prevent a slightly corrupted signal (which is always happening when we submerge our boats in the wet stuff) from trigguring the PCM failsafe.

The PCM failsafes are designed for aircraft use, where the signal is likely to remain strong, and in instances where high speed can lead to disaster in the event of even a momentary loss of signal.

Andy

[turbobearcat]

"Without the ground wire, as

"Without the ground wire, as the brushes spark, you now have a “Spark Gap Transmitter” like from the days of Marconi"


I think I might have left this step out, I will add the extra wire and see if this fixes the problem (ground wire to battery)

once more I search for the truth..

[ramius-ii]

Hi Mark]http://www.subcommittee.com/SubComm/faq_sub_basics.cfm#various
where there is information

Hi Mark]http://www.subcommittee.com/SubComm/faq_sub_basics.cfm#various[/url]
where there is information on "common point ground". The problem with bench testing is there are a ton of signals that can have an effect. Flourscent lights, wireless dog fences, cordless phones, etc., etc., etc. This is what makes grounding so important. Your ground(s) are your shields from unwanted signals. How you run your wiring is equally important. A short time ago, one member wrote a post about running the power wires down one side and signal / control down the other side to keep them seperate. Another technique is to take the power and ground wires, put them in the end of a drill and twist them together.

The receiver has it's own "filtering" to only allow the correct frequency to be processed. This is done via devices such as ceramic resonators, band-pass filters, etc.

Hopefully, all this hasn't given you an Excedrin headache. If you like, you can take some pictures of the wiring and I'll be glad to see if there is anything obious.

Best, Ed