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Author Topic: very hot motor  (Read 7327 times)

timg

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very hot motor
« on: October 05, 2008, 09:25:13 PM »

Hi all
this morning was the 1st outing for my springer (pics later)  and after no more than 3 Min's brought it back in to check and found the motor was very hot
I'm using   2x 6v 4ah batts     545 motor   35mm 4 blade brass prop.
what is the best set up for tug towing/pushing?
any ideas welcome
cheers spud
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Weeds

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Re: very hot motor
« Reply #1 on: October 05, 2008, 10:12:32 PM »

Any ideas to get the motor temperature from hot to cold? Yes, here...

Change motor to one with slow RPM values such as this http://www.vac-u-boat.com/Motor545.htm

OR

Reduce voltage from 12 volts to 6 volts

OR

Change the propeller to speed boat propeller

PS tugboat motor should run cold and draw little amps. :)
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toesupwa

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Re: very hot motor
« Reply #2 on: October 05, 2008, 10:56:31 PM »


this morning was the 1st outing for my springer (pics later)  and after no more than 3 Min's brought it back in to check and found the motor was very hot
I'm using   2x 6v 4ah batts     545 motor   35mm 4 blade brass prop.
what is the best set up for tug towing/pushing?


Are you running 6v or 12v?

Try a 3 blade prop...

Is the motor water cooled?...

How much 'free air' is there in the boat and can you draw some cold air in to the hull any way?
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timg

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Re: very hot motor
« Reply #3 on: October 06, 2008, 08:01:26 PM »

hi all
I'm using 6v ,and a 545 motor like a 540 but with 5 poles (should make it low drain) i do have a MFA 500 and a mmd 555 motor to try thats why i wanted to know what other people have in theres i don't want to make it water cooled if i can help it .
cheers spud
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Martin [Admin]

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Re: very hot motor
« Reply #4 on: October 06, 2008, 08:18:19 PM »

A hot motor is a 'scale' type boat usually means it's over loaded.
First thing I would do, as other have stated, is try different size props and pitches.
You may just find you're over proping the motor!  :)
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FullLeatherJacket

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Re: very hot motor
« Reply #5 on: October 06, 2008, 11:42:00 PM »

a 545 motor like a 540 but with 5 poles (should make it low drain)

Oh no, my son! Don't be fooled by that old tale. I have several 5-pole x 35mm dia motors that would pull your limbs off on 6v, and a 3-pole one that would have trouble with pulling the skin off a rice pudding on the same battery.
It's the thickness and number of the windings that dictate the speed and current drain, not just the number of poles.
Having said that, I'm with Martin; your motor is probably overloaded.
FLJ
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Stavros

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Re: very hot motor
« Reply #6 on: October 07, 2008, 12:10:33 AM »

Get a mota from FLJ got 2 in my springers and they remain cold no need for water cooling good swag!!!!!!




Stavros
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Bunkerbarge

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Re: very hot motor
« Reply #7 on: October 07, 2008, 09:30:54 AM »

Don't forget gents for a constant power output a motor running on 12v taken less current than the same motor at the same speed running at 6V, as Power=IV.

Heat is generated by current so excessive heat indicates excessive current.  The first thing I would try is a 12v battery, this will bring the current down as long as the motor is rated to run at 12v.

Be warned though this will also double the speed of the motor so you may have to either gear down the motor or simply run it slower for your first experiments.  See how it behaves in the bath and if you can't prevent it ejecting the contents you may be better off looking at a slower revving 12v motor or fitting gearboxes to your existing ones.
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timg

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Re: very hot motor
« Reply #8 on: October 09, 2008, 08:35:36 PM »

hi all   thanks for all your advice,i have fitted a MFA 540/1 motor and will test it at the weekend.
i did look at the thickness of the windings, the 540/1 is a 3pole but with alot more windings
will let you have i get on
cheers spud
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Sandy Calder

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Re: very hot motor
« Reply #9 on: October 09, 2008, 09:13:41 PM »

No! No! No!
Look at the performance of the 545 in the Vacuboat link
To get part way there you could try a 550.
Going up to a 12 volt motor like the RE540/2 won't help either.
You need to reduce your prop pitch or add a gearbox or use a motor with a greater torque.
Regards
Sandy Calder
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portside II

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Re: very hot motor
« Reply #10 on: October 10, 2008, 03:34:37 AM »

I have a 540 type motor in my springer to a reduction gear box (the two plastic cog type) and a 50mm brass prop ,pulls a tug twice its size around the pond and it's only on 6v . I agree with the geared method ,works for me.
daz
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Weeds

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Re: very hot motor
« Reply #11 on: October 10, 2008, 04:08:05 AM »

No! No! No!
Look at the performance of the 545 in the Vacuboat link
To get part way there you could try a 550.

excuse me I do not follow your line of thought.. please explain  :-\
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Sandy Calder

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Re: very hot motor
« Reply #12 on: October 10, 2008, 08:51:58 AM »

No! No! No!
Look at the performance of the 545 in the Vacuboat link
To get part way there you could try a 550.

excuse me I do not follow your line of thought.. please explain  :-\
I'm saying to Spud to look no further than that particular 545 for the simplest solution.
You posted a clickable link to its performance.

It will give about 24 watts with a very big prop at 12 volts where the Mabuchi 545 and Re540/1 couldn't turn the same prop
Years ago I got three USPS global priority envelopes of similar 540s.The suppy dried up.
I wonder what vac-u-boat wants for them.
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Sandy Calder

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Re: very hot motor
« Reply #13 on: October 10, 2008, 09:33:28 AM »

The supply dried up  - not the suppy.

I got these motors for ten springer tugs.


This motor is a bit heavier than a 540 sized motor but size and weight is not an issue.
I'm going to charge a local model boat club 10 each. ;)

Regards
Sandy Calder
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Weeds

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Re: very hot motor
« Reply #14 on: October 10, 2008, 07:21:14 PM »

No! No! No!
Look at the performance of the 545 in the Vacuboat link
To get part way there you could try a 550.

excuse me I do not follow your line of thought.. please explain  :-\
I'm saying to Spud to look no further than that particular 545 for the simplest solution.
You posted a clickable link to its performance.

It will give about 24 watts with a very big prop at 12 volts where the Mabuchi 545 and Re540/1 couldn't turn the same prop
Years ago I got three USPS global priority envelopes of similar 540s.The suppy dried up.
I wonder what vac-u-boat wants for them.

So you are saying that the vac-u-tug IS a good tugboat motor?
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Sandy Calder

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Re: very hot motor
« Reply #15 on: October 10, 2008, 09:26:12 PM »

It's like the model trade 545 with a reduction gear.
I've been looking for motors like those for years.

They are sold to the auto industry for car seat retracts.

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Mr Andy

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Re: very hot motor
« Reply #16 on: October 18, 2008, 07:50:21 PM »

I have a 500 in my Springer with a 50 mm three bladed prop she has only been in one like this and was running very hot, I think in part due to the lack of space and as stated free air in the hull, I am waiting to get a water outlet to cool the motor.

Andy. :-)
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Arrow5

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Re: very hot motor
« Reply #17 on: October 18, 2008, 08:38:11 PM »

Mr Andy , try a 3 blade 40mm or even cut one down to 38mm.  I think water-cooling is a must IMHO plus some air circulation.
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Sandy Calder

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Re: very hot motor
« Reply #18 on: October 18, 2008, 09:07:58 PM »

AAAAAAAAAAARGH!

Click on the 545 motor chart at the motor in the link to in Weeds' post.
The bigger the load (propeller) the bigger the current - it's practically proportional to load torque.
The revs is a straight line graph too- downwards.

the motor power is the product of these two lines.
 P(watts)= angular speed(rads-1 x Torque(Nm) is a curve that peaks.

Your prop is TOO BIG or too coarsely pitched.----over the hill.

No need for cooling!


SPUD.
Spud H......n ?
PM if so
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Mr Andy

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Re: very hot motor
« Reply #19 on: October 18, 2008, 09:45:50 PM »

Oh no more expense %) I have the cooling fins on the motor ready just need to plumb it in if I go down that road, I may take your advice and down grade..

Andy. :-)
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