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-   -   Warm motor, warm lipo (https://airsoftcanada.com/showthread.php?t=164011)

Blitz85 April 13th, 2014 20:20

Warm motor, warm lipo
 
Hey guys, sorry if this goes on a bit but I'm going to try and give as much details as possible.
so I'm in need of some advice.
I have recently started upgrading an ics m4, I'm using a merf 3.2 wired in advanced mode with an nano-tech 11.1V 1200 mah stick battery. Stock 18:1 gears ( shimmed twice just to be sure so I'm pretty sure that's not it) and an ics turbo 3000 motor which I am going to upgrade to a lonex A1 within a few weeks. All of the upgrade parts were purchased new from airsoftstore.ca
The problem is that the motor and battery are getting warm after only 10-15 trigger pulls. The upper gearbox isn't even in play so it's not like it's struggling to pull the spring or anything. Now I know motors can get warm with an AB MOSFET but I'm pretty sure a lipo warming up is bad news all over. After enough pulls it stops working which I assume is the fuse being tripped. I have checked the resistance of the wiring and all seems well. The only resistance I find In The whole system the from one end of the merf to the other but only on one side ( positive I think).
That's all the prudent info I can think of, any and all help would be appreciated.

ThunderCactus April 13th, 2014 20:22

bad motor most likely, drawing too much amperage.
What's the C rating on the lipo?
And throw that battery out since it's already damaged

Blitz85 April 13th, 2014 20:26

Quote:

Originally Posted by ThunderCactus (Post 1882731)
bad motor most likely, drawing too much amperage.
What's the C rating on the lipo?
And throw that battery out since it's already damaged

25C, it's this one here : http://www.airsoftstore.ca/index.php...roducts_id=270

Motor was fine on a non lipo battery before I swapped everything out, is it possible that it wouldn't show this problem until a lipo is hooked up?

pestobanana April 13th, 2014 20:46

Are you checking shimming with all the gearbox screws in?

Blitz85 April 13th, 2014 20:47

Quote:

Originally Posted by pestobanana (Post 1882737)
Are you checking shimming with all the gearbox screws in?

Yup, all turn freely with no scraping

ThunderCactus April 13th, 2014 20:50

yes
NiMH mini batteries don't supply amperage anything close to what your lipo does.
Not to mention with the higher voltage, I wouldn't surprised if you're now running at 4x the wattage you were before.

problems like this do occur with airsoft motors, 90% of the motors out there are pretty junky construction.
Most likely you've got a short between the two brush hoods. Looking at pics of the ICS turbo 3000 now, they used metal screws on the brush hoods. If they have a metal retention plate or the screws are touching the magnets, that's your short right there. It'll pretty much draw as much amperage as that short will handle, which is definitely more than your lipo can supply.

Blitz85 April 13th, 2014 21:02

Quote:

Originally Posted by ThunderCactus (Post 1882739)
yes
NiMH mini batteries don't supply amperage anything close to what your lipo does.
Not to mention with the higher voltage, I wouldn't surprised if you're now running at 4x the wattage you were before.

problems like this do occur with airsoft motors, 90% of the motors out there are pretty junky construction.
Most likely you've got a short between the two brush hoods. Looking at pics of the ICS turbo 3000 now, they used metal screws on the brush hoods. If they have a metal retention plate or the screws are touching the magnets, that's your short right there. It'll pretty much draw as much amperage as that short will handle, which is definitely more than your lipo can supply.

Well it sounds weird to say but I do hope that's the problem, as I planned on grabbing a new one anyway. I'm trying to figure out exactly what you mean and you lost me on a few things, don't all motors use metal screws? And what would cause them to touch or get close enough to arc to the magnets? Just shoddy construction?
Also as soon as a lipo gets warm it need to be disposed of?
I wouldn't say it got hot, but definitely noticeably warm.

wind_comm April 13th, 2014 21:28

did you start your shimming from the pinion & bevel?

Blitz85 April 13th, 2014 21:39

Quote:

Originally Posted by wind_comm (Post 1882749)
did you start your shimming from the pinion & bevel?

Started at spur, the motor height has been adjusted and sounds good.
Although I didn't start at the pinion / bevel they seem to be meshing fine, certainly well enough that it wouldn't be causing this drastic of a problem. At least I don't think so lol it can be hard to tell with a V2

pestobanana April 13th, 2014 21:43

If pinion bevel meshing was THAT bad you'd hear it very audibly.

Have you checked your motor brushes? I've had this happen once when a brush wire snapped.

ThunderCactus April 13th, 2014 22:03

all intelligently built motors use plastic screws to fasten down the brush housings to ensure they don't short
if the screws go deep enough, they'll touch the top of the magnets inside the motor
what holds the end bell on the motor is a retention ring, sometimes it's plastic, sometimes it's metal.

Blitz85 April 13th, 2014 22:04

Quote:

Originally Posted by pestobanana (Post 1882758)
If pinion bevel meshing was THAT bad you'd hear it very audibly.

Have you checked your motor brushes? I've had this happen once when a brush wire snapped.

That's what I was thinking about the pinion / bevel.
Yup, brushes are like new. The motor hasn't seen a lot of use.

ThunderCactus April 13th, 2014 22:43

if you have a multimeter, take the brushes out and test for continuity on the brush hoods

wind_comm April 13th, 2014 22:51

Quote:

Originally Posted by Blitz85 (Post 1882755)
Started at spur

there's your problem. doesn't matter if you think it sounds "good", it's just not.

a quick search of ASM or youtube for "bevel shimming" will yield an actual boatload of information on the subject, why you should do it that way and how to do it. (I'm trying to find the video that I used to use to show people but I lost the link somewhere)

compare for yourself what your gearbox sounds like to what a properly shimmed gearbox sounds like and then you can decide.

everybody else is giving you perfectly good advice on how to treat the symptoms you've described, but this is how you treat the disease.

ThunderCactus April 13th, 2014 23:08

I've been shimming gears from the spur for 8 years, I've never run into excessive amp draw from any guns I've built. I've only ever noticed the condition from bad motors.
If you were holding the gear train up enough to cause an amp draw in excess of 40A, you'd be able to hear it for sure and your ROF would go up by an audible amount if you backed the motor off


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