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Author Topic: Running in brushed motor  (Read 1286 times)

glyn44

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Running in brushed motor
« on: February 24, 2017, 03:55:41 PM »

Hi all,
Just been reading build blog( another site, sorry!) and there is suggestions there advocating that a new motor should be run in, to bed down the brushes, in a glass of water. i.e. With the motor submerged. This seems to defy all I was taught about electricity etc. So I'm wondering if this is sound advice, or not, as I'm about to install two motors.


 Your knowledge will be much appreciated, as always.
Glyn.

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nemesis

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Re: Running in brushed motor
« Reply #1 on: February 24, 2017, 04:26:30 PM »

I normally run mine in on the bench, checking amperage and heat for 30mins . A few cycles should do. It is to run the brushes in to a concave profile. If running in water does the job I do not know, I have heard of this system, never had the courage to try it out, nemesis
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malcolmfrary

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Re: Running in brushed motor
« Reply #2 on: February 24, 2017, 05:48:21 PM »

The theory is that using clean fresh water, the waste from bedding in the brushes is removed by the water.  Fresh clean water is not very conductive, so doesn't short everything out.  Also, the brushes would take on the shape of the commutator without burning it.
The motor will need careful lubing after drying out.  Possibly an idea originated by a motor salesman.
Personally, I wouldn't bother unless it was going to be a high performance boat, and in that case I would be looking at going down the brushless route anyway.
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glyn44

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Re: Running in brushed motor
« Reply #3 on: February 24, 2017, 06:33:25 PM »

Salesman technique, like it. Thanks guys I don't think I'll bother with it then. I'll just blow them off with an airline. Anyway the motors are cheap as chips.
Thanks again. Glyn
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grasshopper

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Re: Running in brushed motor
« Reply #4 on: February 24, 2017, 07:25:38 PM »

Water dipping was used by RC car racers ro bed in the brushes on mabuchi can motors.
Jar of clean water, immerse motor and suspend by the leads and connect your 7.2 v pack, run it for a few minutes then disconnect, remove from jar, use a cocktail stick to clear the gaps on the comm,  dry well and lubricate bearings.
The water keeps it cool, softens and clears the carbon dust out.


Alternative slow method used to be connect it to a single 1.2 volt cell and let it run until it goes flat.


It isn't really necessary for low speed applications, it was only really done to get as much power out of a new motor.
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tr7v8

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Re: Running in brushed motor
« Reply #5 on: February 25, 2017, 12:23:44 AM »

Water dipping was used by RC car racers ro bed in the brushes on mabuchi can motors.
Jar of clean water, immerse motor and suspend by the leads and connect your 7.2 v pack, run it for a few minutes then disconnect, remove from jar, use a cocktail stick to clear the gaps on the comm,  dry well and lubricate bearings.
The water keeps it cool, softens and clears the carbon dust out.


Alternative slow method used to be connect it to a single 1.2 volt cell and let it run until it goes flat.


It isn't really necessary for low speed applications, it was only really done to get as much power out of a new motor.
I have done this works well & is quick. It certainly worked when we run a standard 27 turn can.
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Re: Running in brushed motor
« Reply #6 on: February 25, 2017, 08:28:08 AM »

We used to do this on slot car motors back in the 1960s. They were easy to lubricate afterwards, it was a bit of a fad at the time. I haven't bothered since, and as said previously a waste of time unless you are searching for the last bit of performance. I suppose there might be a use in club 500 models.

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Tug-Kenny

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Re: Running in brushed motor
« Reply #7 on: February 25, 2017, 10:52:41 AM »


I see you've mentioned  '27 turn'  in your last post and wondered about the classical definition.

We don't mention  'turns' in boating circles and I wondered if anyone could give us the low down and comparisons to a standard 540 motor, with it's deviations in windings and speed and torque please.

My reason is that I have a  'bucket full'  of old motors and when 12 volts is supplied they all perform with different speeds and torque.

Hoping for clarification

ken
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tr7v8

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Re: Running in brushed motor
« Reply #8 on: February 25, 2017, 08:18:20 PM »

I see you've mentioned  '27 turn'  in your last post and wondered about the classical definition.

ken
Ken when I was racing 1/12 scale on polished wooden floors you ran a ROAR (USA Standards) standard motor. Basically a 540 with a full can (no exposed brushes) with 27turns of wire per pole. As it was a standard motor with no access to the brush gear & oilite bearings you needed to bed the brushes in quickly with no arcing. Hence the glass of water. Always worked well for me.
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Tug-Kenny

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Re: Running in brushed motor
« Reply #9 on: February 26, 2017, 11:27:21 AM »


Thank you for the description.  Can I assume that boaters motors have more turns per coil so that they run slower. ?

ken
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glyn44

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Re: Running in brushed motor
« Reply #10 on: February 26, 2017, 11:59:00 AM »

Ken,
As I remember from my college days (50 yrs ago!) -The lower the number of turns, the higher the power of the motor but a lower RPM. Think that's right.
Glyn
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Tug-Kenny

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Re: Running in brushed motor
« Reply #11 on: February 26, 2017, 12:10:53 PM »

Thanks for the info, it's all new to me. 

I'm still researching it as I have a box of old motors and my only testing method is to connect them to a 12 volt battery and see the speed and thrust.   %)

ken
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mudway

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Re: Running in brushed motor
« Reply #12 on: February 27, 2017, 02:50:10 AM »

I thought it is more turns e.g. 55T results in a lower rpm but more torque. I have a 55T 545 motor which turns at 15,000 at 12v and an 80T which only does 9000 rpm at 12v.
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malcolmfrary

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Re: Running in brushed motor
« Reply #13 on: February 27, 2017, 11:56:25 AM »

Ken,
As I remember from my college days (50 yrs ago!) -The lower the number of turns, the higher the power of the motor but a lower RPM. Think that's right.
Glyn
Time has warped the memory.  A low turn count = high RPM but less torque.  You do get torque from a motor with a low number of very thick windings, but at the cost of a huge current draw, since at low revs it will be operating in virtual stall mode.
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