Neverquit347

Flying my U-Can-Do-EP and the motor just stoped. I think I burnt it out. The speed control is fine. I had to put the orginal 280 in it to fly it. What would make the motor to burn out. I am using the Electrifly C-35 which can handle up to a 600 motor. The motor I killed was a GWS 370. The battery used is a 1500 Electifly 3 Cell Poly. I flew the plane with the 370 for a full flight and it ran great. Why would it just burn out like this.

Thanks John...........

INeedHelp

My Feedback: (1)

A 3-cell lipo is alot for the 370 motor to run with. I have burned up several that way.

Great power for a couple flights but I would go brushless if you can.

exeter_acres

My Feedback: (2)

Yep... a 3 cell lipo is just too much for a brushed can...

sure people will say it can be done... but it won't last long and you can't actually use the throttle

it will last longer on a 2 cell, but the voltage is a bit lower so the power will be too......

pony up for the brushless.. Honest ..you will NEVER go back..

lcbabj

My Feedback: (7)

Exeter is right. I have gone brushless and wish I would have from day one. I am using my 370 brushless on my 3rd model and it is still going strong. Go brushless, it's worth it.

GWR

My Feedback: (31)

But don't they say to use a 3cell on the Tower hobbies site?[sm=spinnyeyes.gif]

Neverquit347

GWR, I agree, why does towerhobbies give you the combo package with the 3 lipo with a 280 motor. It makes no sense. Does anybody have an answer to that. Thanks for all the respone.

wreck_em_all

Tower Hobbies must be smoking strange stuff with respect to the U-Can-Do. The GP 280 and 370 brushed motors are rated for a maximum of 9.6V (the 370). No way these motors should be used with a 3S LiPo (11.1V)! Also, Tower says this plane should not be used with brushless motors. This is just plain nuts!

jdetray

3S lipo can be safely and reliably used with these can motors, but only if you keep the current down to a safe level. There are lots of people using 3S lipo even with the little GWS IPS motors. The trick is to choose gearing and props to keep the amps low.

The rule of thumb is that if you're running successfully on 2S lipo, you can run on 3S lipo if you increase the gear ratio by 50%.

The "other" forum has many discussions about this, with "DeaninMilwaukee" being the resident expert. I don't know if Dean also hangs out here.

- Jeff

Neverquit347

OK, then what can I get to make it brushless. I understand I will have to buy a motor and a brushless ESC, but do have to buy another micro receiever. I have the Futaba Micro FM 4Rx. If I do this means I'll have to buy differant micro servos. Is there a way I can convert this to brushless. Or can I get a brushed motor compatable with my 3 cell lipo 1500, with out it burning up all the time and what prop should I use. Thanks.

wreck_em_all

Just a motor and ESC. More expensive than what you have, but well worth it. I recommend a 370 equivalent outrunner. No gears needed and much more efficient. Make sure the motor is rated for 3S - most are.

wreck_em_all

If you gear/prop down to a "safe level" of current why use 3S LiPos? This procedure limits a 3S performance to that of a 2S. Sorry, your comment makes no sense. I am well aware of Dean. The problem with can motors and 3S LiPos is power density. In essence, a LiPo inputs more Watts into a can motor than it can get rid of. I have a pile of smoked ones to prove it. Gear/proping current down only slows down the motor's destruction. Might work for a while, but smoke will happen sooner or later.

Neverquit347

Thanks wrenk em all. Sorry about the confusion. I just want to have enough power. The 280 can handle the 3 lipo but th power sucks. Where can I get the brushless motor and ESC you mentioned. I'll buy it tonight if I can. I'll be happy with just a brush motor that can handle the battery and will give enough power. Thanks for your patience. I am new to electric. Can't you tell. HA HA

Moe142

My Feedback: (7)

Can I use a 3S Lipo in my plane that has an Endoplasma motor? I have a 35amp Castle Creations lipo compatable ESC. I know I have to make the cut off 3v per cell. will this battery be to many AMPS for a 35 amp ESC? I will also have to get a higher pinion gear and smaller prop.
Thanks!

Neverquit347

OK, would this work. I found these on Towerhobbies. The Ultrafly D/13/32 Outrunner Brushless motor. http://www2.towerhobbies.com/cgi-bin...?&I=LXKKK7&P=0 and the Typhoon 25 Amp Brushless ESC http://www2.towerhobbies.com/cgi-bin...&I=LXGYC9&P=ML

INeedHelp

My Feedback: (1)

For about $133 I would get this and forget about the gearbox all together: http://www.bmkdesigns.net/product_in...products_id=61

I use the Himax outrunners with very good results and the Phx-25 has never let me down either.

Neverquit347

Thanks, but I think I found a great web site. Hackerbrushless.com A20 Series.

INeedHelp

My Feedback: (1)

Hackers are a great motor as well. Enjoy.

BrunswickOH

actually it makes perfect sense! If you keep your current draw at say 8A but take the voltage from 7V to 11V your power will go from 56watts to 88watts, that's quite a jump in performance without any more stress on the motor! You can get great performance out of the little can brushed motors if you take the time to select the proper gearing and propeller. Using a brushless motor doesn't in itself give you more performance it just probably gives you a motor that you can push harder (also pushing your batteries harder which will shorten their life) There is no Magic inside a brushless motor that makes it more powerful.

Jim

exeter_acres

My Feedback: (2)

the hacker A20-20 is my favorite in that weight range!
I LOVE mine... Plenty of power...

wreck_em_all

BrunswickOH,

I guess one man's "sense" is another man's "nonsense." The problem LiPo's have with can motors is primarily voltage and not current. While you are correct in that keeping current the same and increasing voltage yields higher electrical power (P = A * V), you over look the ratio of input thermal Watts (heat) vs. output thermal Watts. Brushed motors lose Watts in the transfer of electricity accross the brush to commutator interface. This is the sparking you see when the motor is running. Brushless motors do not have this problem for obvious reasons and are more efficient as a result (better performance). This is the "magic" in BL motors that helps make them "more powerful." In your example, voltage is increased by 4V. This increases brush sparking and input thermal Watts. Higher voltage yields more sparking. Most can motors are not designed to dissipate the heat levels 3S LiPos dump into them. There are heat sinks that can be put on can motors to help this situation, but don't make it go away. I have smoked 12V 600 size can motors using 3S LiPos with 10A max current draw. The motors simply could not handle the heat. Most 400 and smaller can motors are not rated for use abvove 9.6V. A 3S LiPo is 1.5V over this limit. I doubt a motor manufacturer will honor a warranty claim if some one toasted a 9.6V motor with a 11.1V battery. Also in your example, electrical power "jumps" from 56 to 88W. This does not automatically translate to an equivalent increase in mechanical power to the propeller. Some of this 32W increase is lost in motor winding I2R effect and spark gap loss. The increased heat causes the magnetic field to reduce decreasing potential mechanical power gain.

BrunswickOH

I'm not here to say that brushless motors aren't better, but you're wrong if you're trying to say that increasing the voltage from 7 to 11 causes too much heat in a can motor. It simply doesn't no matter how well worded your post was it's simply wrong. I don't use heat sinks and have no problem with heat at all. This would simply be anecdotal if it were only my experience but it is not. This is done with great success every day all over the world by many many people. If you burned up your Sp 600 motor by going to 3's it's because you had a bad motor or it was set up incorrectly.

The original question was basically "why did the motor burn up" It burned up because voltage was increased without changing the gearing or propeller, end of story. If you want a better brushless setup they are always available if you want to spend the money. If you simply want another $11 motor and to use what you have then that option is also available as long as you change the propeller or gearing.

Jim

wreck_em_all

BrunswickOH,

You are absolutely right. What was I thinking? I guess all my years of electrical engineering has caused my brain to turn to mush and I just start babbling well worded junk. Bad brain! Bad brain!

I never said 3S LiPos could not be used with can motors. You do it, I have done it, many others do it. My point still stands, most can motors are not designed to handle the heat LiPos can input to them. There is a price to be paid for voltage stressing can motors. You can pay it now or pay it later, but you will pay it. I have smoked many can motors with LiPos, some of them with 2S. All in the line of research. My LHS has had much experience with LiPos and toasted can motors. For all the cases where you say it is no problem, I can site cases were the result was charcoal. Again, gearing and propping down a can motor to run on 3S LiPos at "safe" levels does not make sense. This is like tying a knot in a fire hose. You are purposely throttling down the LiPo. So why use the LiPo? Oh sorry - bad brain! Bad brain! If you would be so kind, please look at the windings in your 3S LiPo driven can motor and tell me what color they are. Thanks!

BrunswickOH

A volt is a volt weather it is delivered from a Lithium cell or a round cell you somehow seem to think that Lithium cells are magic in some way. The reason to use Lithium packs is weight, plane and simple end of story. There is nothing special about the voltage coming from a lithium pack a volt from a lithium pack will not generate any more heat then a volt from some round cells. If you use 3 lithium cells or 10 round cells as long as you set up your power system accordingly there is no problem. As for your "look at the windings" comment, is there now magic wire inside a brushless motor?? You will find most 20mm brushless motors are wound with some pretty thin wire.

Let us not argue as it's pointless. The original poster asked why his motor burned up and I say it's because he was pushing too much current through it, you say it's the magic voltage in a lipo cell (sorry couldn't resist one last dig all in good fun)

Jim

Neverquit347

Brunswick OH, I like your opinion because I really do not want to spend anymore money on the electrics. It is something to use at the park. My club is 25 miles away and sometimes it is nice to just go around the corner and fly the electric. I did a lot of researching on the brushless between here and the internet and it is just to much money to go brushless. I would rather put my money towards a four stroke engine.

Its weird, since my first post, I have flown the original 280 motor with a 11x4.7 and it is still going using the same 3 cell lypo. I am thinking about going with another 370 motor but changing to a smaller or bigger prop. What size, I have no idea. I'm hoping you can tell me that. I figure if I burn out another one it is only 13 bucks. The one time I did fly with the 370 it was awesome. I guess I will need to learn throttle control.

Thanks all for your advise.

wreck_em_all

Jim,

Buddy, pal, friend, goombah - you are made of better stuff than that. This is an intercahnge of information and is not pointless. I enjoy giving digs myself. I feel it livens up the discussion and is meant only to be fun. Are you a Harry Potter fan? What's up with the references to "magic?" My reasoning for 3S LiPos being a problem for can motors (you will note that I have been careful to specify 3S LiPos as opposed to a general reference to all LiPos) is based on can motor manufacturer voltage rating and testing conducted by myself. Most (Note I said most, not all) can motors, used in E flight, are rated for 6, 7.2, 8.4, 9.6, and 12V. The majority of can motors in popular use are under 12V. So, a 3S LiPo (11.1V) exceeds the manufacturer's voltage specification (a point I have made before and you seem to overlook). This is a violation of the manufacturer's warranty. Violate at your own risk. To follow your "magic" reference, a 3S LiPo's "magic" is that it supplies more volts than the motor is designed to handle. Power is equal to Volts times Amps. More volts yields more Watts. Just like more Amps yield more Watts. Again, most (not all) can motors are not designed to handle the Watts a "magical" 3S LiPo can supply. Electrical Watts input convert to mechanical Watts and thermal Watts (heat) out. Increasing input electrical Watts whether volts, amps, or both increases prop speed and heat.

My request is based on the fact that the color of the wire varnish used in motor windings darkens with excessive heat. Dark or black wire color indicates the motor is getting too hot. When wire insulation varnish heats up, it caramelizes and then carbonizes if allowed to continue. When insulation breaks down turns can short out to each other. This brings motor winding effective resistance to 0. According to Ohm's law (I = E/R). The result is infinite current draw until major smoke and melted motor wire. Please let me know what color your motor wiring is. Now that's "magic!"