electric motor burns out

[JJFlash]

Say there, I am a newbie to electric rc planes and have been flying a Begin-Air plane with a 480 motor and supplied battery pack. Should the motor get to hot to touch? I have burned out two motors so far and am wondering if I am doing something wrong. Should I cut vents in the plane to get air to the motor?

JJ

[Dr_Who77]

Say there, I am a newbie to electric rc planes and have been flying a Begin-Air plane with a 480 motor and supplied battery pack. Should the motor get to hot to touch? I have burned out two motors so far and am wondering if I am doing something wrong. Should I cut vents in the plane to get air to the motor?

JJ

More than one condition can make a motor overheat:

- Battery pack, possibly to high in cell count, thus excessive volts & amps
- Too large a prop, causeing heavy amp load on motor
- poor ventilation of motor
- WOT all the time, instead of partial throttle flying

Nothing wrong with a warm motor, but if you burn your finger when touching it, thats too hot. Over 140 F. This causes magnets in brushed motor to lose strength and lousy performance. If you glued on prop with CA, thin stuff can run into bearings of motor and cause a binding, = higher amps = hot motor.

Dr_Who77

[JJFlash]

Tnx for info Dr Who, all is stock on rtf plane and I fly 80% of flight at half throttle. Battery packs came with plane. Motor is in tight place with not much venting and its a push type motor so no air flow from prop. Yes, it gets to hot to touch, so I think its a venting problem. I'm not sure how to fix this on a push prop plane. Maybe cut a hole and add a air scoop?

[Dr_Who77]

If you make a vent arrangement, be sure to make an exit point for the air going past the motor. the exit area should be twice or more the size of the inlet vent area.

Dr_Who

[margotcopeland]

You might also want to put a drop of light oil on the shaft at the body of the motor...a SMALL amount. Don't put in in the actual motor through a hole. I find this really helps heat probs and makes the motor run much smoother. It works for me :-)

[JJFlash]

Ok, when new motors arrive I will put drop of oil on shaft and two small air scopes with vent. Will let you know how long motor last. I should be able to tell on first flight by motor temp.

Tnx

JJ

[margotcopeland]

Cool...just let it work in. What your lubricating is the bearings. I do it from both sides, so I lube both the front and rear. I have to stress that you don't want to get oil on the armatures, coils and such, but you do want to lubricate the bearings. I also try not to go WOT (in case you don't know, it means Wide Open Throttle...full throttle).

Most of the time these motors are being pushed to their limits, and most cost about a buck or less (not from the dealer or airplane manufacturer, of course). They use bushings or sleeve bearings, pretty wanky brushes, and are often run well above their recommended voltage.

You can get replacement motors cheaper here:
https://www.jameco.com/webapp/wcs/stores/servlet/CategoryDisplay?storeId=10001&catalogId=10001&langId=-1&categoryId=351530

Or this link if you just want to see them all:
https://www.jameco.com/webapp/wcs/stores/servlet/CategoryDisplay?langId=-1&storeId=10001&catalogId=10001&categoryId=351530&productId=100351530&action=Display+Items

Good Luck!

Margot

[JJFlash]

Thanks for the tips. I doubled the size of vents and used drop of oil on both ends of motor. So far the motor is only getting warm on 15 minute flights, so I think (hope) problem is solved.

JJ

[margotcopeland]

I think you have it licked! Have too much fun, OK?

Margot

[bigkid]

As well as a drop of light oil on the shaft where it enters the brass bush at each end of the motor, I always run in these motors for about half an hour on 2.4 volts, using two AA rechargeable NiMH batteries directly connected to the motor terminals without an ESC. They run better, heat up less and last longer that way.

I have also had great success repowering my Wing Dragon Sportster (aka Beginair) with an Art-Tech brushless outrunner and 3 cell 2200mAh battery, using a 7x5 prop. The increase in power is amazing, and flight times are about 4 times as long as with the supplied battery and Speed 480. See photo attached.

[bigkid]

Here's a picture of one of my speed 480 Wing Dragon/Beginair motors being run in.

[margotcopeland]

I know this sounds strange (at least it does to me), but I've read about running a new motor for an hour UNDER WATER to break it in. Does anyone know about this, and whether it works? I don't dare try!

[bigkid]

Yes, I've heard of it, but have not actually done it. The idea is that the arcing (sparks) that cause pitting of the brushes in a new motor and stop the brushes shaping themselves neatly to fit the commutator cannot happen if the motor is underwater. My method of running in at a very low voltage achieves the same thing, because the arcing does not happen at the low voltage. Running underwater at normal voltage would do it quicker. When you run it underwater the water will start to go grey because of the carbon wearing off the brushes.
The only reason I don't do it is because I think it would be quite hard to get all the water out of the motor afterwards. I believe people blow air through them to do this.

[margotcopeland]

It makes sense. I just purchased some J250 motors, and I think I'll the water method on one to see what happens. Your method sounds less messy, and I don't have a source of compressed air to dry out a bunch of motors. Thank you for the tip and the info! :-)

[JJFlash]

Tnx for the tips. I will break my next motor in that way with 2 aa batterys. How did you mount your brushless motor? I did have to make motor mounts out of metal strips cuz the motor kept coming lose in HI-G loops and knocking prop off. Never have found any that came off. I did notice the Dragon seems to be same plane but a lot cheaper except for s&h. Can you get them in US?

Old Kid

[margotcopeland]

There are about 4 on eBay right now. There's two models, one 3 and one 4 channel, and it seems there's an updated Wing Dragon 2. They're ranging from 69.00 to around $100.00 on eBay...H-L has them on sale for $99: http://www.hobby-lobby.com/wingdragon.htm

I've seen some good reviews on them.

[bigkid]

To mount the brushless motor I cut from balsa wood about 8 mm (3/8" approx) thick a bulkhead that I put inside the fuselage just where the Speed 480 used to bolt on. I drilled out the 3 holes in the motor mounting plate to 3 mm and drilled through the balsa bulkhead so I could put 3 mm bolts right through the motor mounting plate, the fuselage plastic and the balsa bulkhead.
The tiny nuts and bolts supplied with the motor are much too short for my purposes. I bought the 3mm bolts at my local hardware store.