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Author Topic: Can a Brushless Outrunner be too Powerful?  (Read 5164 times)

essex2visuvesi

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #25 on: April 06, 2013, 01:20:09 PM »

Never paid any charges on stuff from HK. Pay attention to the checkout process and you can see how you can avoid this sort of thing.


Yes there is.... and also try to avoid any service that uses DHL or Parcel Force
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More Coffee

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #26 on: April 07, 2013, 11:41:06 PM »

I know i'm in Canada but , generally I keep my orders below $50 , even if it means breaking up the order over a week ..
However its been my experience that every thing Ive had that come in over $100 I get hit.
 
DHL,UPS,FedEx .. it depends ,find out if your shipping charges include the brokerage fee , Ive had various items delivered by all of them , usually with no extra charge or I knew I would have to pay brokerage fee's ..
Good luck.
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kinmel

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #28 on: April 08, 2013, 07:53:25 AM »

These are a popular low reving motor with plenty of torque

http://www.giantshark.co.uk/xyh5055-400kv-brushless-outrunner-p-403284.html
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Tug Fanatic

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #29 on: April 08, 2013, 02:40:53 PM »

Thank you for the suggestions - these are still big motors..
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Mad_Mike

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #30 on: April 08, 2013, 08:25:58 PM »

found a brushed 900 motor:
http://www.ebay.co.uk/itm/MODEL-BOAT-MOTOR-900-HIGH-TORQUE-LOW-REV-12v-24v-CALDERCRAFT-/200912606867?pt=UK_ToysGames_RadioControlled_JN&hash=item2ec7531693
775:
http://www.ebay.co.uk/itm/NEW-775-Hobby-Motor-18V-36V-2000RPM-Great-for-R-C-Boat-Apps-DIY-/281052956575?pt=LH_DefaultDomain_0&hash=item41700fc79f
i think if you want to get the really low rpms but still cheap, id consider buying a cheap motor be brushed or brushless and rewind it to suit your needs, that or a gearbox. Im looking for car fan motors on ebay. Are we talking about the radiator fan or the heater matrix fan?
 
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Tug Fanatic

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #31 on: April 09, 2013, 09:16:55 PM »

Either.
 
I traditionally used the heater matrix motors because they were often protected from the weather but still easy to get at. I then found a very cheap source of new Smiths heater motors but they are now all gone. Unfortunately heater motors have increasingly become buried in the dash but if buying new then that is not a problem. This is a Smiths motor that I used to get but these have a lower stall current than the previous ones that I used - but it does look the same.
http://www.distel.co.uk/asps/details1.asp?ID=NQ34
or
http://www.ebay.co.uk/itm/Ford-Transit-Heater-Blower-Motor-Dash-Fan-10-until-end-of-March-2013-/251248736080?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3a7f977750
 
Others have used the radiator cooling fan motors which is what I think that I will move over to using as if nothing else I can go round some garages to have a look at them! They vary considerably is shape & size. This is an example only as I haven't even seen a City Rover cooling fan.
http://www.ebay.co.uk/itm/City-Rover-RADIATOR-COOLING-FAN-AND-MOTOR-NEW-/251256081387?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3a80078bebize.
 
 
The other motors that have now arrived are the scooter motors which are used in the ride on model railway world but again I haven't tried one. Most are about 2800rpm apparantly:
http://www.ebay.co.uk/itm/Kids-Electric-Scooter-Replacement-Motor-120w-24v-/120633881162?pt=UK_Sporting_Goods_Scooters_LE&hash=item1c1656f24a
 
http://www.petrolscooter.co.uk/spare-parts/all-parts-by-type/electric-motors-parts.html?p=1
 
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Mad_Mike

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #32 on: April 09, 2013, 10:29:34 PM »

why is the lower stall current on this motor:
http://www.distel.co.uk/asps/details.asp?ID=38018NQ34&ER=0.673&CY=USD&AP=21.92
an issue? If you were to stall the motor then it would have a good chance of still working rather than burning out itself and/or the esc.
They seem to be at the same going rate as brushless motors.
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Tug Fanatic

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #33 on: April 10, 2013, 08:46:27 AM »

It isn't an issue except that I ran mine at about 5 amps which is above the stall current of this one. Mine stalled at nearer 10 amps. It suggests that there are at least 2 different power versions of this motor.
At 5 amps they don't get above tepid - although to be fair in a tug you don't use full power very much at all + I always measure the load static so it is probably a lot less at speed.
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Mad_Mike

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #34 on: April 10, 2013, 07:53:34 PM »

this lower stall current would suggest that the motor has more turns and lower kv that your usual motor.
regaurding the static test and im probably wrong but although there is a drop in amperage when the boat is moving i dont think the drop is much unless its a steep pitch propeller. Besides weather the tug is static in the domestic tank or pulling a load in the lake in both circumstances it is subject to propslip. Anyway do you know what you want to do then?
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Tug Fanatic

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #35 on: April 10, 2013, 09:37:11 PM »

As I understand it a scale prop has a pitch 1 to 1.5 times the diameter. The motor in question turns a 80mm prop at around 2500 rpm.
 
2500rpm x 60 minutes x 0.08metres(80mm) x say 1.4 (pitch) = 16.8kph or 10.4mph. I would have thought that say 4mph of model speed would have reduced the load on the motor considerably - but I am probably wrong as well.
I do know what I am going to do. Thanks you.
 
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Subculture

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #36 on: April 11, 2013, 08:15:13 AM »

Most model props are pitched to the ratio of 1-1.5 times diameter. I'd say for electric power you're better going for the lower figure, as you get less slip. Steam models are usually lower in RPM so they need a coarse pitch prop to get the best out of torquey, but slow revving engines.

Even good model props slip a lot more than their 1:1 counterparts, so the model will probably go a good bit slower than 10.4mph at that shaft speed.

Mad_Mike

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #37 on: April 11, 2013, 09:48:50 AM »

As I understand it a scale prop has a pitch 1 to 1.5 times the diameter. The motor in question turns a 80mm prop at around 2500 rpm.
 
2500rpm x 60 minutes x 0.08metres(80mm) x say 1.4 (pitch) = 16.8kph or 10.4mph. I would have thought that say 4mph of model speed would have reduced the load on the motor considerably - but I am probably wrong as well.
I do know what I am going to do. Thanks you.
so erm... what motor you going with then?
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Tug Fanatic

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #38 on: April 11, 2013, 10:47:05 AM »

I am going to go & measure some of the cooling fan motors that are available new on ebay at local car dealers both to measure them & to look at the fans that they are driving to get some idea of their characteristics. I expect to buy the best (I hope) of them.
 
I would be very tempted with one of the scooter motors but 24v is a bit of a killer and 1400rpm unloaded on 12v is not enough.
 
I am looking at brushless for a smaller model that I am contemplating as I was very surprised to be told by Nick75_au above that some of the motors that I already own + their cell packs (3S 2200mah) will work for such as model. That way I will get a bit of experience of brushless in boats.
 
   
 
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Mad_Mike

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Re: Can a Brushless Outrunner be too Powerful?
« Reply #39 on: April 11, 2013, 11:16:18 PM »

Ill probably be picking your brains on your findings then %) :D
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