HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 03, 2002, 09:49 AM
Registered User
United States, VA, McLean
Joined Oct 2000
21 Posts
how do you tell when your motor's going bad

I was flying my soarstar with the stock motor over the weekend, and on the first flight with the second battery I started to get some surging in the motor. I noticed this during a low and slow fly-by at 15 feet off the ground 20 yards away from me, at about 1/4 throttle. The effect was almost as if I had punched the throttle a little and then released. Instantly I became worried and went around and landed. Since a soccer team was arriving anyway to use the field, I figured it was about time to go home. I'm pretty sure it was not radio interference.

Is this anything to worry about? If so, what should I be worrying about? What are the symptoms of a motor wearing out? (This is the second season I've used the motor right out of the box and I have never done any maintenance, break-in etc.)

Hopefully someone can help.
waagbuck is offline Find More Posts by waagbuck
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 03, 2002, 09:57 AM
Registered User
San Antonio, Texas USA
Joined Feb 2001
1,108 Posts
How old is the motor? Sounds like a glitch maybe? Have you ever put some oil on it?
cruzomatic is offline Find More Posts by cruzomatic
Reply With Quote
Old Jun 03, 2002, 12:02 PM
Registered User
United States, VA, McLean
Joined Oct 2000
21 Posts
how old is the motor

It's a year old, with light usage by most standards (ie I don't fly it that often). No oil's ever been put it in.
waagbuck is offline Find More Posts by waagbuck
Reply With Quote
Old Jun 03, 2002, 03:17 PM
soft yummy goodness.
freq's Avatar
North Jersey, USA
Joined Oct 2001
735 Posts
Timing is probably about right for the Speed 400's life expectancy in this appication. Mine don't last nearly as long in a Zagi with higher current draw.

Speed change could be related to bushing or brush wear. As the brushes wear down, they can create more sparking which can also lead to radio glitching.

Horizon Hobby used to sell a replacement motor complete with gearbox for around $20, but I can't find it on their site today. Strange as it was there a few weeks ago. If your gearbox is fine (keep it greased and ballbearings oiled), you could just replace the motor with any $8 6V Speed400.


-chris
freq is offline Find More Posts by freq
Reply With Quote
Old Jun 03, 2002, 08:28 PM
Registered User
San Antonio, Texas USA
Joined Feb 2001
1,108 Posts
I agree with freq. After a year,,it's probably had it. You might want to try some electric motor cleaner. It's what the car/truck guys use to clean their electric race motors. Your LHS should have plenty. Give that a try, that may help.
cruzomatic is offline Find More Posts by cruzomatic
Reply With Quote
Old Jun 04, 2002, 01:01 AM
Registered User
Temagami, ON, CA
Joined Mar 2002
75 Posts
Resistance?

When i had my ESC fry, someone said it may be the motor. They said to check resistance, which I measured and it was 0.3 ohms, measured on the 200 scale. I checked my new (never used) Graupner motor. It was about 33. Figured motor was bad and replaced. I soldered wires to the new motor, and the capacitor from pole to pole from the old motor, and started break-in. Measured ohms before break-in and was still at about 30. After 15 minutes on a single d cell, the ohms are down to .3

Is this an indictation of a problem? Should I be worried about plugging my new ESC into this new motor now? Is my old motor still ok?

Anyone know if resistance is a way to check for motor problems?

Thanks,

Mike.
Iglooman is offline Find More Posts by Iglooman
Reply With Quote
Old Jun 04, 2002, 03:00 PM
Registered User
United States, VA, McLean
Joined Oct 2000
21 Posts
which electricity meter?

Thanks for the input everyone. I'll look at getting a replacement motor. In the meantime, I'll try to test the ESC. Does anyone have any recommendations on the electronics meters for this (or other issues)? I see the posts recommending chargers are all over the board, but maybe there is some consensus here.
waagbuck is offline Find More Posts by waagbuck
Reply With Quote
Old Jun 04, 2002, 05:40 PM
soft yummy goodness.
freq's Avatar
North Jersey, USA
Joined Oct 2001
735 Posts
Ah ha! Finally found the SFM direct replacement for the Soarstar. Horizon Hobby part # SFM2032 $18. Includes motor & 1.85:1 gearbox.
http://www.horizonhobby.com/products...032&pc=SFM2032


-chris
freq is offline Find More Posts by freq
Reply With Quote
Old Jun 04, 2002, 06:11 PM
Registered User
Pennsylvania, USA
Joined Dec 2001
26 Posts
What often happens with these 380 & 550 Mabuchi style motors is that the brushes wear down so far that the spring arm can no longer hold enough tension on the commutator to make a good enough connection for the high currents we fliers tend to need.

I don't know if that's your problem for certain, but I have experienced the same "surging", and it was due to brush wear. The brush wasn't completely gone, just so thin that it wouldn't make good contact at the lower spring pressure.

You could upgrade to something with replaceable brushes, and those motors tend to have more consistent spring pressure as the brush wears. But at one motor per year, you're not doing bad.
dxed is offline Find More Posts by dxed
Reply With Quote
Old Sep 23, 2002, 07:53 PM
Registered User
stevem1928's Avatar
Nebraska
Joined Apr 2002
598 Posts
Quote:
you could just replace the motor with any $8 6V Speed400.
Where do you get the $8 motors?
stevem1928 is offline Find More Posts by stevem1928
Reply With Quote
Old Sep 23, 2002, 10:21 PM
burning holes in the sky
jjs63james's Avatar
thunder bay ont. near(55605)
Joined May 2002
98 Posts
Here is a Great place to get sp 400 zagi motors !
$7.99 Can. funds

http://www.greathobbies.com/frame_index.html

just type in ghp013 into the search box.
,James
jjs63james is offline Find More Posts by jjs63james
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How do you know when your main motor is going on a HBFP? mdavenport Micro Helis 8 Mar 19, 2007 07:10 AM
How do you tell when a Li-poly battery shot? jmiceli11 Batteries and Chargers 6 Dec 15, 2004 09:34 PM
how can you tell when your to lean? obin Fuel Heli Talk 5 Feb 19, 2004 07:42 PM
How do you know when your motor is toast American Flyer Parkflyers 12 Jul 08, 2003 03:28 PM
How do you tell when an ESC is gone? spy0o7 Power Systems 4 Oct 30, 2001 04:32 AM