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[leachim]

I think I have just done a really stupid thing and would like some assistance to understand where I went wrong.
Just finishing off my Ulyses tug kit that my darling wife bought me for my birthday last year. Needing to check out what ballast I need it went in the bath this afternoon.
While it was there i decided (probably wrongly as it turns out) to test the drive. Turned everything on and all seemed ok rudder moved and motor ran albeit backwards but that's just a quick reversal of wires to the motor so all ok, or so I thought. Slowly reversing down the bath the motor stopped and the esc let out a wonderful puff of smoke and all went dead.


I am running an MFA RE 540/1 motor off a 6volt NIMH pack through a Mtronics Viper Marine 15 plug & play ESC swinging a direct coupled 40mm brass three blade prop. No i didn't have a fuse inline as i said this was only a first test in water, it all worked fine on the bench.


1) Have I got a duff ESC?
2) Is the motor wrong for the boat? If so what shoul I have bought?
3) Should I have bought a larger ESC? If so which one?


I have read a lot on this forum regarding motors and ESC's which left me thoroughly confused and bought what i thought was the correct combination for my boat which is 830mm long x 180mm wide.


Thanks in advance for your assistance


Mike

[Martin (Admin)]

 

Adding reference photo for ...... reference!

[Martin (Admin)]

1) Have I got a duff ESC?
2) Is the motor wrong for the boat? If so what should I have bought?
3) Should I have bought a larger ESC? If so which one?

 
1. Possibly. Motor could be bad or shorted out. Shaft tightened up. Have you got / do you know how to use a multimeter?
2. The RE - 540/1 - (3 POLE) is a bit of a speed merchant, the RE-540LN (5 POLE). NOISE ATTENUATED is a better
     choice for a tug. ( same physical size, different winding ).
3.  Nothing wrong with the ESC, I've got several, never had a problem. Next time, try a fuse ( or self re-seting circuit breaker) in-line with the motor.
     https://www.modelboatmayhem.co.uk/forum/index.php/topic,64475.msg683269.html#msg683269

 

[Klunk]

its mtroniks. enough said. i have boxfull of these.
now seriously, check that the prop is freely rotating, not stiff, hard to turn or binding.
is the coupling as straight as possible, not off center. did you grease the propshaft?

[GG]

Mike,
       Having been a satisfied user of Mtroniks  ESC's for many years, I'd first check that the drive-line (from motor to prop) can turn freely.  Ideally you ought to be able to (with no power to the RC of course!) rotate the prop using a finger tip on one blade with no significant effort.  In fact you ought to feel the resistance as the motors poles move past the magnets.


If not then locate were the "stiffness" is, as others have suggested misaligned motor/prop shafts, poor coupling and not enough free play in shaft due to badly placed lock nuts.


As for grease in the prop tube, I try to avoid it as it can create a lot of viscous drag between the rotating shaft and fixed tube.  Oil, with a properly adjusted drive line works for me, even in my submarine models.


Also a thought, although perhaps not the cause of this problem in this case, a 40mm diameter prop might be a shade too large for this motor and direct drive?
Glynn Guest

[Colin Bishop]

If the drive is jammed then when you changed direction it might have wound the prop and locknut against the tube end. However the specs of that motor suggest that it would have drawn nowhere near 15 amps in a stalled condition so it might be the ESC at fault.

Lots of people say they never bother with fuses but I always do...

Colin

[Tug Fanatic]

This is a strange one as the 6v stall current of that motor is listed as 8.24 amps. Even if fully stalled, for whatever reason the esc should have survived it assuming that you didn't leaves it like that for an extended period for it all to overheat.


To my mind that leaves the most likely explanation as either a faulty esc or a short circuit somewhere in the wiring between the motor and the esc - including the motor and its connections.

I agree with GG that the prop might be slightly large for the motor but as this is the combination that has powered 000's of Springers you are on safe ground.

[malcolmfrary]

1) Have I got a duff ESC?
2) Is the motor wrong for the boat? If so what shoul I have bought?
3) Should I have bought a larger ESC? If so which one?

1  You have one now that the magic smoke has been let out
2 Marginal if you were running on the max volts for the motor, but on 6 volts should have been fine.  As [stated earlier, a 540 on 6 volts has been the recipe for Springers for many years, albeit with a slightly smaller prop, usually with three blades.
3 Probably not.  As suggested earlier, if a badly applied locknut was involved, this would act as a very effective brake on the shaft as it disconnected from whatever it was supposed to lock and got shifted the wrong way up the shaft by the shaft's rotation.

[roycv]

Hi sometimes these things can seem very difficult to sort out, may I suggest you contact a local model boat club and ask if you could show an experienced member your problems?
An experienced eye may spot what is wrong or at least give you a start at sorting it out.  I have been there with mystery faults which took all the electronics out, it happens!
Good luck.
Roy

[leachim]

Thanks everyone for your input.


I have double checked everything out this morning. The motor runs direct from the battery and the shaft rotates easily so no problem there. I retried the ESC, the rudder turns ok (so BEC is working) but the motor won't drive - not unexpected as the magic smoke has all escaped. My son in law (an electronics engineer) educated me last night, apparantly all electronics work using magic smoke in a closed circuit, if the smoke escapes then nothing works! Lol!


I have double checked all connections and cannot find a short, the Viper claims to be short circuit protected anyway so shouldn't have let the smoke escape. I can only assume that my ESC had a faulty magic smoke safety valve that got stuck open and let all the smoke escape from the motor drive circuit  .


This morning I have ordered a replacement ESC along with the MFA 5 pole 540 motor that some have recommended as when it did work it seemed a little aggressive. Hopefully I will get these next week sometime and be able to schedule a maiden voyage (if the weather ever settles down).


Thanks once again for all your assistance. I will keep you posted.


Mike

[Tug Fanatic]

As it was new and you seem to have excluded anything that could be your fault I would send the broken esc back to Mtronics explaining what happened and enclosing a copy of proof of purchase. If it was faulty they should send you a new one.

It sounds like one of those situations where anyone can make a mistake but what differentiates good from bad is what they do about it.

PS - That is one nice looking model!

[chris gillespie]

Mtroniks have always been really decent to deal with

Never had a quibble from them in sending back the damaged esc's