dude7422

want to keep com true? run motor at real low speed i have done this to keep
the com true and brushes after many hard runs cheap fix

hypercorecomputers.com

Whats better Brush or Brushless?

mrasmm

The answer is it depends.

Some of what it could depend on is how much money do you want to spend, is the motor likely to be used in a situation where it's better if it is disposable (like mud boggin in an r/c truck), how important is spool up time (brushed motors spin up faster because of the direct input, vs the sensor driven modified a/c of the brushless, ie brushless direct drive on a heli's tail will really have to be tweaked to get similar performance as the inexpensive brushed versions), are you past the learning curve to the point where you feel like you are ok risking a bigger investment, etc.

Brushless generally makes more efficient use of power (ie less wasted as heat compared to brushless). If you take care of the brushless they have many times the lifespan of the brushed motors. It also could depend on if you want more power for your r/c, because they waste less energy as heat, you can generally put a bigger motor in for the same run time and have more power, or put a motor in that puts out the same power as the brushed and get longer run/flight times. If your brushed motor is a bit underpowered for the application, ie it has to run at the peak the whole time to get it to do what you want, they tend to burn out quite fast, and brushless would make sense there. Also if your motor is more enclosed so it traps more heat, brushless makes more sense since it is more efficient, ie produces less heat for the same powered motor.

For that heli in the pic you're looking at a belt drive tail, and those usually work better for a brushless upgrade than the direct drive tails. So if you have the money and you want to try it out, it might be worth it.

katoace

I'm breaking in my xtreme se's right now thanx bro.................Kato

grosbeak

Newbie question - Ihave a Hobbyzone Super Cup LP that has not been run yet. Do Ihave to desolder the motor from the plane to break it in?

Thanks... great tutorial.

mrasmm

Hey there. It looks like you have
http://secure.hobbyzone.com/HBZ7300.html

It looks like the motor has some quick connectors on it from this picture
http://secure.hobbyzone.com/search/HBZ7134.html

If you want to break in this motor, there may be a few more things to think about. I've never seen this ARF personally, so I'm going blind. Normally during a break-in you'd take the motor out of the aircraft to prevent heat build up, unless it's well ventilated where it's at. A lot of aircraft rely on the airspeed and propwash to get airflow over the motor to cool it down. So that's something to keep in mind. Usually you would take off the load (ie propeller) and run the motor at a low voltage, and you don't usually get too much heat buildup that way.

I don't think I would go to the extreme of desoldering a motor to break it in (especially when a new one is only $10), all though you certainly could.

Hopefully that helps you out. Feel free to write back if you still have q's

grosbeak

Thanks for the tip. Iremoved the spinner, prop and cowl and Isaw the wires soldered onto the motor lugs... I didn't see connectors between the motor and firewall so perhaps they are inside the fuse - Iwill have to take a look.

I actually have the BNF version (vs the RTF you linked too) but Ican't imagine the motors are too different.


Another question - will AAAs provide sufficient current for a proper break in? I happen to have some on hand (not so AAs)


Thank you!

mrasmm

You're welcome.

OK, this one then
http://secure.hobbyzone.com/search/HBZ7380.html

I'm not quite sure what the diff is between BNF and ARF, other than you put the pieces together from the box instead of having them already put together...

But yeah, I'm not sure what the resistance on the core winding is, but I think aaa's should be enough. Mostly it's the mAh vs the mA that you'd be looking at (ie how long you run the motor to break it in for). Typical aaa's have less than 800mAh whereas AA's have more like double that. C's and D's have even more. So you may have to use some extra batteries to get the break in time you're after.

I personally use a PSU that lets me vary the voltage and the current. I haven't done a lot of battery break-ins

grosbeak

From my limited experience, BNF means you supply the transmitter only. ARF is a misnomer - I looked at a gas ARF trainer. Sure, it's almost ready to fly... once you buy the plane you just need an engine, transmitter, receiver, servos, batteries... IMHO, SRF(Somewhat) or NRF (not) would be more truthful!

Guessing by your OP, anything over an hour is gravy... or am Imissing something?

mrasmm

ahh gotcha. So it comes with everything but the rx and tx? What an ARF really should be =P

yeah, sounds about right.

I do break-ins with my PSU. So what I do is run it on a constant voltage, variable amperage. I note what the amps are to start out with. Then I watch it. As the motor wears in, the amps needed goes down. When I am good with what kind of power it draws, then I called broken in =) That'd be harder to do with batteries, so yeah, an hour should be good.

Temps are another good way. Temps are basically a function of efficiency or in other words, amps. So when the brushes seat, the motor will become more efficient, and have less heat than when you started out.

grosbeak

Not quite - it comes with everything but the transmitter... 2.4 GHz DSM2 receiver is installed. I bought the Phoenix flight sim c/w Spektrum DX5E trx. The RTF version is 72 MHz.

I do have an infrared temperature sensor... perhaps that would help. And would it be possible to measure the draw with a multimeter while breaking it in?

mrasmm

ahh, IC. I didn't see a way they could have an rx in there, but I guess if it's for dsm2 then there ya go.


Yes on both accounts. This motor should start around .3A and work its way down to about half that if I was guessing. Most multimeters have a 10A capacity. Just hook it up in series. Make sure you have your leads connected in to the right places on your multimeter.

grosbeak

mrasmm,

Thanks loads - for the tutorial and the extra support.


I hope to do the break in this week - I'll reply with my temperature and amperage data when I'm done. Will get some AAs first, though.

grosbeak

Ithink Ihave it figured out...


Motor break in diagram by JD and Beastlet, on Flickr

... please correct me if I'm wrong!

mrasmm

You're welcome =)

So what you have here is a parallel setup. You're looking for a series set up. To get it correct, when you look at your diagram, it should look like a circle.

So lets start with the + lead of motor, that should hook to the + side of the AA (either 1 or 2), the - side of the AA should hook to the + side of the multimeter, the - side of the multimeter should hook to the - side of the motor. Hopefully that makes sense.

So in your diagram disconnect the - side of the multimeter and the + side of the battery. Then take those two leads and hook them together.

mrasmm

One other note. Make sure you do this or you could get a fried multimeter. So the black lead plugs into the common, and the red lead is going to plug in to the Amp receptacle (vs volt or mA on most multimeters)

grosbeak

Thanks for the clarification.

I tried that setup but no power got through. I'm guessing that the multimeter is too light - its three DCA settings are 2ma, 20mA, and 200mA. Instead, Ijust hooked the motor directly to the battery and let it run for almost two hours.

mrasmm

You've probably got to change the position of the red lead on your multimeter. If you look on your multimeter, it probably has 3 red ports and 1 black port. If you take a pic of it and post it here, I'll show you what I mean =)

grosbeak

Not mine... it's hardwired, without removable leads.

mrasmm

Got a pic or a brand and model #?

Here's one you can get for like $3 bucks on sale or $5 bucks normally



http://www.harborfreight.com/7-funct...ter-90899.html

If you look, it has several places to put the leads. If your multimeter has mA on the dial (as well as voltage), then it's gona have to have some way to be able to change the leads.

grosbeak

This is the one:



It's difficult to see, but the DCA range is on the left (three selections). One review mentions the hardwired leads. Next one Ibuy will have detachable leads!

I after running the motor for two hours Ithought about it, then reconnected the batteries and let it run overnight. The batteries were dead in the morning - down to a combined 0.25VDC.

I think it's broken in! Thanks again for all of your help.

mrasmm

Gotcha. Actually this DMM has an internal switch that switches automatically between an ammeter and a volt meter. See the manual on page 25.
http://downloads.thesource.ca/220/22...als/manual.pdf

The main problem is the fuse in this DMM is only 315mA. This motor might pop that fuse; it'd be close either way.

Sounds like you ran those batteries good and dead =) It should be ready to go then

and you're welcome