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[T33cno]

In jest

[unbuiltnautilus]

One of our members has a 1/6 scale WWI Mark 1 tank. This suffered from the whine from the motors at low speeds. Not very realistic sounds for the actual engine sound module to fight against. Turns out is is a direct consequence of the frequency the speed control operates on, and there aint nowt you can do about it. Options were either lower or higher frequency controllers, mostly re-engineered units from Germany at an appropriate price!
On the subject of Mtroniks controllers, don't knock em till you have been selling them for twenty years. I stand by them on the proviso that you don't push your luck with them. For example, the model mentioned previously, pulling about 10 amps on two motors. Don't fit one little 10 amp unit. Build in a safety margin. Twin screw set up, stick at least a 20 amp unit in. Covers you for those little balls ups that occur from time to time. Balls ups which undoubtedly account for a large number of Mtroniks units being cooked by the less wise members of the boaty community. ( Other speed controls are available, and are, these days, pretty good. Unless  they cost a tenner from China....those ARE tat! )

[T33cno]

The ones I removed were 40 amp each    and a separate 15 for bow thruster

[Nordlys]

A  reply to Stavros and to those who also posted in reply.
Look, what I'm going to do is test run my Launch on Sunday with current set up,
I don't know yet how well this motor is going to move the boat, then I'll
sort out an Action Esc next week after speaking to Dave is it?
Thanks all....very helpful posts.
Nordlys

[Nordlys]

In conclusion then, should I be looking at something like the Action P80s at £43?
Running off main battery only?


Nordlys.

[unbuiltnautilus]

The Action units seem to be designed in such a way to eliminate the whine problem common with some other types of speed control, and if they were not fit for use, the Internet Business Assassination Squad ( IBAS ) would have put them out of business years ago ..


I think the whine problem has to be a combination of motor type, number of poles and speed control operating frequency..I shall have to look at a bench test in the future..not forgetting my fire extinguisher..sounds vital

[Peter Fitness]

Despite what Stavros says, I have been using Mtroniks ESCs for nearly 15 years and have never had a single problem with any of them. I don't dispute that some people have had trouble, but I have nothing but praise for them. I also have an ACTion P94 which is a brilliant unit, having dual ESCs and a mixer built in. ACTion equipment is beautifully built, but quite expensive to buy here in Australia, so in my case it is basic economics.


Peter.

[malcolmfrary]

In conclusion then, should I be looking at something like the Action P80s at £43?
Running off main battery only?


Nordlys.

Always pays to read the info right to the end. - http://www.componentshop.co.uk/p80-condor-20-2-autoset-computer-speed-controller.html -
The P80 does not include a BEC, so either a receiver battery to run the radio or a discrete BEC to get the 5 volts from the main battery.
Some useful information here - http://www.modelboatmayhem.co.uk/forum/index.php/topic,6169.0.html


All modern ESCs control the motor by switching it on and off very rapidly, that determines the frequency but whether it can be heard or not depends on the ESC itself, the motors number of poles and nature of windings and its interaction with the ESC, and whether your ears respond to that frequency.  Personally, I appreciate some sound - it lets me know that something is happening.  The early ESCs gave their output at 50 Hz which gave a low grumble, some of the modern ones that you can't hear might excite the interest of any passing dogs.

[Nordlys]

I did read that too! But where do you connect the 5v Battery to?
I thought there would be a wired plug on the board?


Nordlys

[malcolmfrary]

The drawing in the component shop link just shows what the ESC connections do.  The receiver battery or separate BEC plugs into the "batt" connection on the receiver.  Electricity can flow either way along the wire unless someone has put something in to stop it, so 5 volts appearing at the receiver will feed out to the control circuits of everything plugged into the receiver.  The information in the other link is old, but still valid.  Worth a look.

[aeronut]

Aeronut, can you (or anyone for that matter) list the "frequency change" ESCs that fall within his spec and price bracket?

Sorry, there's far too many ESCs and their variants for me to maintain such a database.

[HMS Invisible]

Rest assured, I am NOT taking a pot shot but you did state

Some ESCs allow you to change switch frequency, which may or may not help.

It most certainly does help to alleviate by avoiding those frequencies annoying to the human ear. I did extensive proof tests as a due diligence measure before prominently plastering the bold text (on item list number 5, below) on my homepage.
Can anybody else find "frequency change" ESCs that fall within the opening poster's spec and price bracket"?  There are hundreds in his county of Kent but manufactured and sold by yours truly.


unbuiltnautilus, you should be finished an hour after closing shop as all you need are the enclosed can Pittman motors, 3 and 5 pole Mabuchi motors in cans of various size.

1) An ESC that "suffered from the whine from the motors at low speeds"  switches around 3.3kHz
2) You mentioned tenner a time Chinese ESCS. These usually switch at 2kHz.
3) Plenty of older, low frequency speed controls. around frame rate of 50 to 100Hz
4) A yellow no-name brand that you took for a swim . That one switches around 1kHz but has a radio fail warning in the form of a modulated chirp on an audible carrier between 3kHz and 4kHz. (You'd think an audible alert is configured to be difficult to miss, no?)
5) A silvery no-name brand that lists " * choice of 4 operating frequencies for smooth and quiet operation" (488Hz, 976 Hz, 1.952kHz & 3.904kHz)


And here are some links to sound samples   523.25Hz    1.0465kHz   2.093kHz   4.186kHz from source https://en.wikipedia.org/wiki/Audio_frequency

[unbuiltnautilus]

Rest assured, I am taking a pot shot but you did state  It most certainly does help to alleviate by avoiding those frequencies annoying to the human ear. I did extensive proof tests as a due diligence measure before prominently plastering the bold text (on item list number 5, below) on my homepage.
Can anybody else find "frequency change" ESCs that fall within the opening poster's spec and price bracket"?  There are hundreds in his county of Kent but manufactured and sold by yours truly.


unbuiltnautilus, you should be finished an hour after closing shop as all you need are the enclosed can Pittman motors, 3 and 5 pole Mabuchi motors in cans of various size.

1) An ESC that "suffered from the whine from the motors at low speeds"  switches around 3.3kHz
2) You mentioned tenner a time Chinese ESCS. These usually switch at 2kHz.
3) Plenty of older, low frequency speed controls. around frame rate of 50 to 100Hz
4) A yellow no-name brand that you took for a swim . That one switches around 1kHz but has a radio fail warning in the form of a modulated chirp on an audible carrier between 3kHz and 4kHz. (You'd think an audible alert is configured to be difficult to miss, no?)
5) A silvery no-name brand that lists " * choice of 4 operating frequencies for smooth and quiet operation" (488Hz, 976 Hz, 1.952kHz & 3.904kHz)


And here are some links to sound samples   523.25Hz    1.0465kHz   2.093kHz   4.186kHz from source https://en.wikipedia.org/wiki/Audio_frequency

Nobody asked what the best ESCs were, otherwise you would have got a well deserved nod


Yup, the link shows my sub with Microgyros ESC and Auto leveller, Action Twin Relay Switcher AND Mtroniks Failsafe, plus MFA RE360 reversible pump, twin Pittman motors and 9.6v NiMh from Component Shop. I am an equal opportunities model maker, and no hum was evident at any time..
He who shouts loudest is not always, by default, correct

[HMS Invisible]

The four Wikipedia sound samples are a good guide if you are bothered by the sound.


500Hz can just be heard but is high enough to be beyond rotor mechanical resonance that affects the older, low frequency controllers. It also equates to 30,000rpm so a higher switching frequency is needed for very high rpm motors.


2kHz to 4kHz is the frequency band to avoid for if motor whine bothers you.


I didn't give a link to other sample frequencies. As the switching frequency goes beyond this, the high amplitude chopped current becomes more dc+ripple and less rectangular, chopped dc. There is little noise-causing vibration to hear even if you had the ears of a bat. Brush arcing also disappears in the tens of kHz but that comes at the expense of increased size and cost in the esc.