Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: 1 [2]   Go Down

Author Topic: facts on Brushless Motors  (Read 13075 times)

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 19,052
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: facts on Brushless Motors
« Reply #25 on: September 04, 2007, 12:03:59 PM »


If the motor has 3 or more wires coming out of the motor it needs a special (brushless) ESC
BTW: Most brushless ESC are non reversing.

Logged
"This is my firm opinion, but what do I know?!"    -   Mayhem FaceBook Group!

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: facts on Brushless Motors
« Reply #26 on: September 04, 2007, 01:00:50 PM »

MMMMMM, yer, but do they produce much heat? cant see that they would produce more than the traditional motor but this is going to have very little air flow.
might have to fit a small fan on the motor.
well see
colin
Logged
grumpy old XXX

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: facts on Brushless Motors
« Reply #27 on: September 04, 2007, 02:06:34 PM »

They get warm like any other motor, Colin.

The main efficiency gain of these motors is through the elimination of a commutator and carbon brushes.

So without any airflow over the motor i.e. encased in an outboard shell, a fan may be a good idea.

Andy

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: facts on Brushless Motors
« Reply #28 on: September 04, 2007, 04:13:54 PM »

Ta, just as i thought. another problem to solve. oh goody!
colin
Logged
grumpy old XXX

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,563
  • Location: Blackpool, Lancs, UK
Re: facts on Brushless Motors
« Reply #29 on: September 05, 2007, 12:44:35 PM »

Much of the heat generated in normal motors happens in the brush/commutator area, so you dont have that to contend with when using brushless motors.  But, when extracting as much performance from any motor as you can, you will warm it up quite a lot, and it will certainly benefit from some form of cooling.
Logged
"With the right tool, you can break anything" - Garfield

Model Boats Website

  • www.model-boats.com
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 39
  • Model Boats Website
    • Model Boats Website
Re: facts on Brushless Motors
« Reply #30 on: September 08, 2007, 11:24:00 AM »

Right, here we go, to answer some of you're questions:-

You dont need a brushless ESC for brushless motors.

You only need a 'special' ESC when using Lipo cell packs instead of NimH or Nicad packs. This is because Lipo's have different characteristics and must be switched off when the voltage gets down to a certain level else the pack is ruined.

Justboatonic: No! You're completely wrong! It is necessary to have a brushless controller with a brushless motor. A brushless motor needs a controller to switch the current to the different coils in order to make it spin!

And YOU DONT NEED LIPO'S TO RUN A BRUSHLESS SYSTEM! any batteries will do!

Yes, brushless motors are much more efficient, however they do struggle at low speeds, so it's not really advised to use them on smaller boats. Also as Martin said, there is currently a very limited range of controllers that will do reverse as well. You do see them advertised as "reversible" but this means you have to do it manually, so be careful of that one.

To Colin-Stevens: Yes these motors can get hot, however it is hard to burn them out because theres nothing to burn out! The magnets may loose their magnativity and if you over do it too much you might melt the coil.... possibly? Never done it! You can buy out-runner motors where the whole outer casing spins around, these provide more torque and run much cooler.

To understand a little more about the differences between brushed and brushless see:-


colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: facts on Brushless Motors
« Reply #31 on: September 08, 2007, 10:07:20 PM »

Acheers fireboat, seems i already have a spin out motor. am going to mount it on an ally block to help with heat and make some holed where they wont be seen. i dont want reverse as it is for a rib and will swamp, so reversing is not a concern in this instance.
seems to be ok at low speed,but havnt tried her in anger as yet, that is a long way off. and as these motors seem to be designed to spin a large prop, my little one may not be a problem. we will see. everything about this project seems to be suck it and see.
joy!
colin
Logged
grumpy old XXX

Garabaldy

  • Guest
Re: facts on Brushless Motors
« Reply #32 on: October 27, 2008, 08:41:09 AM »

How is this project going colin?  Have you made any more progress with building the outboards?
Logged

sunworksco

  • Guest
Re: facts on Brushless Motors
« Reply #33 on: July 20, 2009, 08:39:30 AM »

The brushless motors run cool if they are not geared or the prop is sized correctly.The motors run cool because the windings are usually next to the motor can and more readily dissapate the heat.The ESCs get hot at any speed but most quality ones have heat sinks or optional fans.Water cooling is an easy option as well.Here is an image of Novak's products that are sensored and programable for low/high speeds.Works well for scale low/walking speeds.
Logged

Captain Povey

  • Guest
Re: facts on Brushless Motors
« Reply #34 on: July 20, 2009, 09:12:21 AM »

Hi all, I have fitted a small brushless outrunner motor in my Mincio (see postings and photos), bought from a local model shop. No problem with heat. I tried to cut costs by using a cheap speed controller (non reversing). Not worth it as I ended up buying a proper programmable, reversible boat speed controller from Westbourn's. I also used a LiPo battery to save weight and space. Cheers Graham.
Logged

monarch

  • Guest
Re: facts on Brushless Motors
« Reply #35 on: July 20, 2009, 09:36:45 AM »

Hi
On the question of heat, they will stay cooler than brushed for the same power in so the heat build up is all dependant on what load you put on it.  They can be easily water cooled if Inrunner but not so easy for Outrunner.  For scale boats outrunners are far lower reving but as mentioned earlier to get any brushless motor to run as slow as brushed needs a sensor but thats what normally fails and reduces reliability. Hope this helps and don't confuse the issue any more.
Logged

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,721
  • Location: South Cumbria
Re: facts on Brushless Motors
« Reply #36 on: July 20, 2009, 11:23:05 AM »

Just a thought about reversing brushless motors. Would it not be possible to fit a reversing switcher between the esc and motor, you only need to switch over 2 of the 3 connections?

Ian
Logged
if at first you dont succeed.....have a beer.....

andrewh

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,064
  • Location: Melbourne, Australia
Re: facts on Brushless Motors
« Reply #37 on: July 20, 2009, 12:13:50 PM »

Ian,

Great minds, etc.  Yes it is possible and I have done this in the "werdna BL reverser" - this is reported on a little with pictures in the brushless basics thread:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=13538.0
 and
http://www.modelboatmayhem.co.uk/forum/index.php?topic=14068.0

I did mine with two microswitches arranged to changeover any two wires of the brushless motor, and it needed an extra channel as designed.  Incidentally its is identical to the gadget needed to reverse a brushed motor - so it could be used by anyone who has a aircraft ESC (or no ESC) to reverse a brushed motor. 

The wires are switched at zero throttle and no current so there is no issue of switch  or contact rating - only the need for the microswitch to be able to handle the max actual motor current.

andrew
Logged

Captain Povey

  • Guest
Re: facts on Brushless Motors
« Reply #38 on: July 20, 2009, 12:34:54 PM »

Hi All, I did not have any space for extra switches in the little mincio and the Westbourn speed controller when properly set up for a boat has a good soft start and low speed capability. Cheers, Graham.
Logged

cmpang

  • Guest
Re: facts on Brushless Motors
« Reply #39 on: December 27, 2009, 06:24:09 PM »

Hi All,

I have been using brushless motors on RC planes for over 5 years with great success. But now is the first time I put an out runner in my 1.2m Sumner class destroyer and discovered that the running sound it makes semms to build up acoustic resonance with the FG hull. It is even more serious while running in low speed and during times when the speed changes.

Does anyone experience that great noise while running out runner?

Logged

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 19,052
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: facts on Brushless Motors
« Reply #40 on: December 27, 2009, 06:41:07 PM »


What kind of noise?
Logged
"This is my firm opinion, but what do I know?!"    -   Mayhem FaceBook Group!

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: facts on Brushless Motors
« Reply #41 on: December 27, 2009, 06:55:20 PM »

Logged

cmpang

  • Guest
Re: facts on Brushless Motors
« Reply #42 on: December 28, 2009, 02:18:45 AM »

Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: facts on Brushless Motors
« Reply #43 on: December 28, 2009, 02:31:52 AM »

yep thats quiet to some I have heard some of the noise sounds a bit like coupling noise though, the one I posted is twin motors so is a bit noisier..

Peter
Logged

jabba

  • Guest
Re: facts on Brushless Motors
« Reply #44 on: December 28, 2009, 06:46:51 AM »

Hi guys
why don't you buy a castle creations mamba max esc you can run brushless or
brushed motor of this one,
i have a springer tug running a brushless motor,750kv outrunner ,it use's  2 x  lipo's .it only pulls 1.5 amp w.o.t.
so run times are well all day. no strange noises here either.

jabba.

brushless all the way
Logged
Pages: 1 [2]   Go Up