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Author Topic: MFA large motor?  (Read 5637 times)

Rob47

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Re: MFA large motor?
« Reply #25 on: May 15, 2021, 01:49:27 pm »

what sort of speed controller would the mfa Barracuda motor need for 12 volt or for 24 volt operation.
im not realy into electric stuff, but have seen a load of cheap esc on ebay and wondering if these realy would do the job
I know the specs of the motor show 4 amp on load at 12 volt and 6 amp on load at 24 volt.
but when simply running this motor through a battery charger I find you realy have to put a lot on this motor to get to 4 and 6 amps.
I know boat props do like  a bit of power , the model will not be a heavy weight monster by a long way. say a max all up weight of around
14 to 18 pounds depending if I go 12 or 24 volts. I will probably just run something like x 50 to x55 prop so only about 2.5 to 3 inch pitch.
I am not after it being mega fast , just 10mph ish so its quick enough to get out and tow back in a broken down boat.

ive seen these and wondering if they would be ok or if these are gimics and I would be better off fitting the old manual type


Used two of these in my HMS Hermes 1/96  running through elctornize esc, plenty of power and never an issue.


Bob

speed controller from a 7.2 volt Tamiya car ?
I like the idea of the electric speed controller but only ever had one once and blew it up 20 odd years ago.

https://www.ebay.co.uk/itm/124260779562?epid=27004439599&hash=item1cee85062a:g:EG4AAOSwUjhfDqLo

https://www.ebay.co.uk/itm/124260779562?epid=27004439599&hash=item1cee85062a:g:EG4AAOSwUjhfDqLo

https://www.ebay.co.uk/itm/153263230580?epid=12008784758&hash=item23af334e74:g:JLEAAOSwXAxb7rD7.

if these are no good for my sort of purpose is there anything recommended on the cheap

.
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phillnjack3

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Re: MFA large motor?
« Reply #26 on: May 15, 2021, 03:23:31 pm »

i just have no idea about the modern stuff and was wondering if the esc like advertised is realy what it says it is and ok for my needs.
seems extremely cheap to me ?



would this realy be ok for the Barracuda witha  bit to spare ? its saying 320 amp !!!!  is that possible




https://www.ebay.co.uk/itm/124260779562?epid=27004439599&hash=item1cee85062a:g:EG4AAOSwUjhfDqLo

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Stan

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Re: MFA large motor?
« Reply #27 on: May 15, 2021, 06:49:10 pm »

Not knowing the spec of this  E S C  I  would think that amount of current could not be sustained for a long time. On page one there is the spec for this motor and I shows it to draw very little power. Have look at the hobby wing 1060  E S C.


Stan
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Colin Bishop

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Re: MFA large motor?
« Reply #28 on: May 15, 2021, 07:21:34 pm »

The late, great Dave Milbourn would have said that figures like that are essentially meaningless and he shoulkd have known.

Colin
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john44

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Re: MFA large motor?
« Reply #29 on: May 15, 2021, 07:33:27 pm »

Yes Colin Dave would have certainly said that, the esc Stan referred to would be more like the correct one to go with.
You say you may run at 24 v these ESC run at 12v max if you look at car ESCs beware some run at 7.2v.max.


John
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Tug Fanatic

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Re: MFA large motor?
« Reply #30 on: May 15, 2021, 08:50:15 pm »

Total fiction.

If you look closely you can see that the motor wired are stamped 16awg which has a nominal current capacity of 22 amps. The Tamiya type connector on the battery lead is undesirable at less as they are prone to overheating and bad contacts.

Even those numbers might be more than the rest of the circuitry will cope with.
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chas

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Re: MFA large motor?
« Reply #31 on: May 15, 2021, 11:24:14 pm »

Yes, I know that esc, forget it for your motor. Just buy a decent one, action and mtronics are my go to ones, but modelers all have their favourites. You put a lot of time and effort into a model, don't risk it with a company that deliberately misleads you with it's specifications.
  Charles

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john44

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Re: MFA large motor?
« Reply #32 on: May 16, 2021, 09:01:39 am »

I would not like to be in the Chinese test lab when they test the 320 amp CARRYING capability of that ESC.
TO CARRY A 320 amp load you need 90mm2 cable at least {-) {-)


John
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Tug Fanatic

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Re: MFA large motor?
« Reply #33 on: May 16, 2021, 09:21:00 am »


I would not like to be in the Chinese test lab when they test the 320 amp CARRYING capability of that ESC.
TO CARRY A 320 amp load you need 90mm2 cable at least {-) {-)
John

I guess that it might do it for a nano second.  :police:  :}
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JimG

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Re: MFA large motor?
« Reply #34 on: May 16, 2021, 11:03:16 am »

These quoted currents are from the data sheets of the individual switching FETs . Basically this is the maximum instantaneous current they can switch without immediately burning out and is basically for transient pulses. It is however much greater than the actual continuous current they can carry, this depends on how well it is cooled, wire sizes, traces on the circuit board etc. Quoting the instantaneous current makes the ESC look much better than it would if it was the actual working maximum.
Jim
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phillnjack3

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Re: MFA large motor?
« Reply #35 on: May 16, 2021, 04:29:38 pm »

this is what I cant understand about this model stuff.
320 amp seems a hell of a lot to me, I would think you need wire 12 mm thick to cope with that.
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JimG

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Re: MFA large motor?
« Reply #36 on: May 16, 2021, 06:26:14 pm »

this is what I cant understand about this model stuff.
320 amp seems a hell of a lot to me, I would think you need wire 12 mm thick to cope with that.
When the very high current is only for around a millisecond it doesn't matter what the wire guage is.
Jim
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Stan

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Re: MFA large motor?
« Reply #37 on: May 16, 2021, 06:51:21 pm »

HI Guys once again a post going round in circles. The most amps this motor draws is 6 amps you state you are going to run it on either 12 or 24 volts if this is the case M troniks  make a controller that will handle both voltages. But you pays your money and makes your choice cheap is not always the best
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Colin Bishop

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Re: MFA large motor?
« Reply #38 on: May 16, 2021, 07:01:46 pm »

Quote
320 amp seems a hell of a lot to me, I would think you need wire 12 mm thick to cope with that.

No model boat draws that sort of current, it is nonsense. That current level would blow your house wiring!

As Stan says, stick with a reputable UK supplier who know what they are selling.

Colin
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phillnjack3

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Re: MFA large motor?
« Reply #39 on: May 16, 2021, 08:04:49 pm »

you say "Uk supplier"
so its ok if not actually made in the uk as long as someone is selling it here ? is that what you mean ?

Or do you think these components and the building of everything is all uk ?

stan.. you started off moaning its all going round in circles, and yet contribute ? I am surprised you didn't simply scroll past ?
And by the way the motor specs says 6 amps under load @ 24 volt. im pretty sure if you were stall it completely then will go up a lot higher.
ive just hit 10 amps on 12 volt stalling, might be higher but my simple ammeter I had handy only goes to 10..

and yes Colin I agree most of the amps stated on all this model stuff is way off of a real amps. especially the 320 amps as advertised in the advert  that I posted. maybe these are phantom amps ?

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Stan

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Re: MFA large motor?
« Reply #40 on: May 16, 2021, 08:33:36 pm »

First of all lets set the record straight I am not moaning just trying like others to point you in the right direction. If you are happy with your choice of speed controller so be it. You ask for advice then throw back to the  very people who are trying to advise you. My contribution to this post is quite simple what information are you seeking you seem to have all the answers. 
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Colin Bishop

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Re: MFA large motor?
« Reply #41 on: May 16, 2021, 08:34:33 pm »

If you buy from a UK supplier then yes, the item could have been made in China but the UK supplier is likely to have assessed the product and you will have an after sales comeback and support should you have problems.

The late Dave Milbourn, who knew about these things, was very dismissive about the claims from Chinese suppliers. He ought to have known as he built ESCs for a living and I would have alway trusted his judgement.

You pays your money etc....

Personally I always like to support UK manufacturers/suppliers. Their customers are usually happy.

Colin
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chas

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Re: MFA large motor?
« Reply #42 on: May 16, 2021, 10:10:41 pm »

Phillnjack, you did ask for advice, you've had plenty, all based on experience and first hand knowledge, and all saying pretty much the same thing. If the advice wasn't what you hoped to hear, that's unavoidable. Whether or not you plan to save 15 to 20 quid, and take a risk with the esc from a company that can't even give honest specifications is up to you. I value the work and time that I put into a model too much to risk it.
 One last point, I said earlier that I did know those escs, I've had one, non linear speed control, lagy, poor wireing, I could go on.
  Your choice, I've said my piece.
Charles

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cos918

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Re: MFA large motor?
« Reply #43 on: May 16, 2021, 10:24:36 pm »

you say "Uk supplier"
so its ok if not actually made in the uk as long as someone is selling it here ? is that what you mean ?

Or do you think these components and the building of everything is all uk ?

stan.. you started off moaning its all going round in circles, and yet contribute ? I am surprised you didn't simply scroll past ?
And by the way the motor specs says 6 amps under load @ 24 volt. im pretty sure if you were stall it completely then will go up a lot higher.
ive just hit 10 amps on 12 volt stalling, might be higher but my simple ammeter I had handy only goes to 10..

and yes Colin I agree most of the amps stated on all this model stuff is way off of a real amps. especially the 320 amps as advertised in the advert  that I posted. maybe these are phantom amps ?

the 320 ah is only momentry . Most chines stuff quotes momentry and not continus.
The key to seeing through chines BS is look at the wire used and the conectors and the size of the thing.
Mtronis are built in the UK with componets sourced from all over the globe.


John
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phillnjack3

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Re: MFA large motor?
« Reply #44 on: May 17, 2021, 05:12:42 pm »

.i will be going with a much lower rated esc.
I think 20 amp will be enough witha  fuse ?

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Howard

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Re: MFA large motor?
« Reply #45 on: May 17, 2021, 05:39:37 pm »

Phillnjack3
 you have been a member for 14days yet you have a pop that Stan and Colin who know what they are talking about, Colin has over 11000, post Stan nearly as Many both have been giving great help to members new and old for years if you don't like what what they then do what you told Stan stroll on by don't come and ask for advice then be so disrespectful you might like what great modellers like Stan and Colin say but lots of us other members do.
         if you think you know better you may be better on another site.
              Regards Howard.
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Martin (Admin)

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Re: MFA large motor?
« Reply #46 on: May 17, 2021, 06:02:37 pm »


Topic locked   :police:
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