Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[dazzle]

Though i have been using brushless motors and esc in my boats for last 4 years and other than a musical ok tone first then silent after, except in my tug now gone which had an early electronize esc which was silent, can anyone recommend a modern brushed esc that does not make an annoying beep, tone etc every time the tx throttle stick is moved from neutral to forward or reverse as most of the j perkins and chinese ones do.

mick

kept meaning to post a chart of all my brushless motor, esc, lipo, prop used, boat weight, length, hull type wood etc,
and performance, duration, ill health has stopped me

[HMS Invisible]

...an annoying beep, tone etc every time the tx throttle stick is moved from neutral to forward or reverse...

Do you mean a whine (like the two clickable links) which disappears at full throttle?
Audio Frequency tone, C7, 2093hz
Audio frequency tone, C8, 4186hz

[Sonar]

The answer has to be electronize...

[dazzle]

A single audio tone/bleep is emitted when the tx stick is 1st moved from the center position, pitch/ frequency of which depends on esc used. very loud and will ruin any engine sound system or video etc of the boat.

I did not know electronize were still trading, just looked at their speed controllers they are still using relays in them, in todays age of solid state electronics,  i will not use an esc with an old fashioned relay the contacts corrode go dirty,
springs on moving parts go weak, relays go out of adjustment contacts will arc and burn out, jam together in open  or closed position cause a short circuit etc, electronize is a no no.
so i still need an alternative brushed motor speed controller that does not make a loud bleep/tone and does not have a relay in it.

[malcolmfrary]

As has been discussed many times before, PWM controllers all work by switching on and off rapidly.  This results in a waveform being applied to a moving inductive component. In other areas, this is called a "loudspeaker", but in those areas the sound effect is assisted by fixing a piston to the moving part.  The only ways out are to either use a control that runs at ultrasonic frequency so you don't hear it but passing dogs do, or something old like a Hitec gold brick (50Hz) which causes the motor to growl.  Or design your own linear type (or use an old Bobs Board) and heat up the insides of your boat.  Or use a resilient mounting to damp the sound down.  Technology will probably need to move on a bit before control chips can run at a high enough frequency to result in a motor control frequency that cannot be heard and still have good control.
Not using a relay type is your own choice, but not one of the reasons quoted is valid in regard to the ones used in decent model control devices that have been professionally designed, specified and produced, especially when used properly.  Relays do have a life expectancy of several million operations if used within specification, so reversing once a second continuously would take a month to wear it out.  Even when time (several years for a model with average use) has taken its toll, a relay is cheap and easy to replace.  I have had the odd broken Electronize passed to me, usually it has either been dunked (salty water messes anything up) or connected incorrectly.  Since they are made of accessible, replaceable components, they were fixable.  A sealed box is a replaceable module.  When (not If) it dies, it stays dead.

[dazzle]

Looks like will have to go brushless with this one if can get a very low kv small in size outrunner as most low kv ones are too large in physical size, also i use only direct coupled motor to shaft rubber couplings not gearboxes or belt band reduction pulleys,  boat is a 1940s before even boat kits were made, bread and butter wood construction  thames river launch.

thank you for your replys

mick

[pompebled]

Hi Mick,

This firm produces brushed ESC's that are quiet after the initial powering up:
https://www.modellbau-regler.de/shop/index.php?language=en&MODsid=n26elp81ki6pkgc64ktj4c7fl0

I had a similar issue, ruining the runs I recorded with the Mobius camera on board my tugboat; the whining of the ESC switching in the windings of the motor blanketed the recording with unwanted noise.
I got this ESC and the boat is completely silent:
https://www.modellbau-regler.de/shop/product_info.php?products_id=90&MODsid=n26elp81ki6pkgc64ktj4c7fl0

Proof of the pudding:
https://youtu.be/wUIt1F0iSyY

Regards, Jan.

[HMS Invisible]

I have not had such an issue, Jan.
See the second item in the list. Link

[dazzle]

Having 60 years experience of electronics taught by my father I built my first valve oscillator/transmitter at 7 years of age,  a 0 - 1 binary logic computer using relays, torch bulbs  etc at age 8, (anything with an ic in it works on 0 - 1 logic even today), my own radio control equipment at 11, the 1st sound to light unit powered by the earphone socket of the very first kit built transistor battery radio before colored light bulbs and discos were heard of, plus that used in most hobbies, both as a hobby and working in every field  of electronics and also used in electrical and most other industries, maintaining, fault finding designing and testing, programming, my last job before retiring was head of test and research in an electronics company, also I have enough  certificates to decorate a rooms wall with, I have worked on valves transistors, ics, fets, right up to the latest smt technology used in mobile phones and other equipment and future electronics not even available to the general public  yet,  all dc and ac motors from early magnet and field coil ones to stepper  and large 3 phase motors, even 1 years ago powered by  a lemon cut in half,  r c tx rx, servos, actuators, escs etc.

Re post 4 not one of my reasons quoted is valued, i have  encountered every relay fault i mentioned from post ww2 relays used by the g p o  to those used today, i would suggest malcolmfrary you have been lucky, and as an esc uses p and n channel mosfets for motor forward and reverse, a relay is not needed, my early electronize in tug i sold did not have  a relay, it used power mosfets same as todays esc do, though i could easily design and build an esc i do not have the time.

Thank you ever so much Jan and Microgyros i will be on the phone to both places tomorrow.

Mick

[malcolmfrary]

Heavily used relays and relays used out of their electrical limits will suffer mechanical wear and arcing damage reducing their life expectancy.  But the ones used in model ESCs are generally well within limits, and are at least as reliable as sealed H bridges.  I say that having seen more dead H bridge types than dead relay types where the damage was to the relay.  Usually, being sealed, the relays used are safe from the commonest cause of failure, namely a tech adjusting it.  This after spending most of my working life in a relay-rich environment.  My only qualm about relay type ESCs is the current taken by the relay coil when it is held operated.
Personally, I prefer a bit of sound as it lets me know that something is likely to happen shortly.  I did prefer the 50Hz grumble from when the ESC timebase was derived from the transmitter frame rate, modern high frequency types are still a compromise between output switching speed and fine control, largely limited by the speed of the processor in the control chip.  This will be true for both H bridge and relay types.  Until very recently, it was a close thing between whether a relay was or was not bigger and/or heavier than the extra three power transistors and their associated heat sinks, often the single relay cost less and offered a more compact solution.
But each to his own, you makes your choice and you pays your money.

[dazzle]

If you had looked at the relay on that new electronize esc, just one glance tells me its maximum current through its contacts is approx 2/3 amps, a 540 motor using a 35 to 40 mm prop depending on the weight of the boat will pull an initial short surge when the boat starts to move of anywhere between 12 to 15 amps before dropping back to running  current of approx 4/5 amps, which is still beyond the maximum rated current the relay contacts can handle, weed jamming a prop will cause the current through the motor to rise even higher, the contacts will melt even as the fuse if used blows.

Escs whether early transistor or powerfets do not need large heat sinks because  the pulse is a very short duration.  if you had read my last post more carefully the n channel fet drives the motor in one direction the p channel fet drives it in the other, the same as using earlier npn and pnp transistors or 2 npns on there own or 2 pnps depending on which way one decides to design the circuit.  A relay to reverse the motor is Not needed.

Re limited by the speed of the processor, A quad core processor old generation running  between 8 or 12 ghz in speed is too Slow.

The Ad 12 bit frame rate on most of todays spectrum, jr,  futaba, hitec etc tx rx and on digital brushless motor servos and other switches etc, is 5 years out of date but not slow.

Yes each to his own

When I come on mayhem and ask a simple question, or in the past when I have answered one to help someone,
I will not be belittled by anyone on electronics, or made to be seen as if I do not know what I am talking about,
also applys to electrical and mechanical problems that I have had to solve in the past by practical work on them. 

[inertia]

 Dazzle
Being asked to consider another point of view is not the same as being belittled. That said, if your attitude appears even remotely like “my way or the highway” you’ll find it often goes down badly on Internet forums. Take that from one who knows.

On the matter of reversing relays in speed controllers, I owned and ran a successful model boat electronics business for almost six years, and I have continued to do most of the repairs of the units it produced. In that time I estimate that I have fitted something in excess of 25,000 relays specifically placed for reversing the direction of a main drive motor. Most are rated at 8A continuous. A very small percentage were found to be faulty from new and these were replaced before the ESC was packed and sold. Those apart, I think I must have had maybe twenty units back in ten years for repair due to damaged relays, and most of those relays had been damaged by the heat from an adjacent MOSFET which had been overloaded. Four or five had welded contacts but, being sealed units, corrosion wasn’t considered. Overloading a relay-less speed controller will also cause damage without current- and thermal-overload protection, and so up goes the complexity and the cost.
I have to agree that you don’t need a relay to reverse a motor and that an H-bridge of N and P channel FETs will also do the job. The fact remains that relays are cheaper to fit and easier to test and replace, or we would all have gone over to semiconductors a long time ago. Because SMT relays are not available with usable current ratings for model motors the choice of MOSFET H-Bridges for modern speed controllers is pretty much Hobson’s.
If  Malcom Frary really is very lucky, there must be one hell of a lot of other lucky people out there. Maybe they just like that reassuring “click”?
Dave Milbourn
(ACTion RC Electronics)
 

[dazzle]

Dave,

I do not wish to argue with anyone, also i do not have an attitude problem of my way or the highway,  there is a difference between  considering  another persons view, which i will always do, than being told not one of my reasons is valid, when i have experienced many times every single one of those reasons for not using one from ww2 surplus relays to the latest ones used now.

Mick

[malcolmfrary]

The more you practice, the luckier you get, whether designing or using.  There is a big difference between switching and carrying - the reversing relay will should only be switching in the dead time between forward and reverse when zero power is being applied to the motor, hence the general lack of anybody having a problem.  It was sort of built in to the old ZN409 circuits, no doubt a PIC or similar chip could be programmed to slam into reverse at full power when a relay with really meaty contacts would be needed.  But that doesn't happen with commercial ESCs.  The output FET gets all the pain after the relay contacts are comfortably settled.
Older transistors of whatever type needed a heatsink because the pules, when at full speed, were not pulses, just one long one.  The "on" pulses are only short when at low speed.  The pitch of the tone is constant because the frequency remains the same, the mark/space ratio is what is varied and accounts for any change in volume.  The transistor in its "on" time acts as a resistor at whatever resistance it can settle down to.  The very modern ones do have a remarkably low on resistance, but still need help to carry high currents.