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-   -   Push starting a brushed motor? (https://www.rc-monster.com/forum/showthread.php?t=21612)

cmcclive 06.15.2009 09:42 AM

Push starting a brushed motor?
 
I picked up a duratrax evader for the wife (I have a T4 she wanted to bashed with me once). I have noticed sometimes it seems to like to be push started, aka the motor will not move the vehicle unless someone pushes it alittle, it will not start from an unmoving position.
She is currently running a 27T stock brushed motor and a VXL ESC (had it sitting around).
What would be the likely culprit? Bad ESC? Bad Motor? Bad Battery? I am guessing/hoping it is the motor, just wanted some other opinions first.

Thanks

Slowkrawl 06.15.2009 09:49 AM

I noticed the stock motor in my slash would do this to me. I finally got tired of buying garbage brushed motors and went brushless. If you already have the vxl esc, find yourself a vxl brushless motor and you will never go back!

BrianG 06.15.2009 10:20 AM

I would say it's the motor. Worn brushes may develop uneven wear, or are just dirty and the electrical contact of the brushes could be between commutator connectors.

cmcclive 06.15.2009 10:21 AM

Quote:

Originally Posted by Slowkrawl (Post 295851)
I noticed the stock motor in my slash would do this to me. I finally got tired of buying garbage brushed motors and went brushless. If you already have the vxl esc, find yourself a vxl brushless motor and you will never go back!

That is what I am consitering doing, I just wanted to make sure the was replacing teh correct fault part first.

Thanks for the info though (similar issue fixed by motor change).

Metallover 06.15.2009 11:13 AM

If you clean/replace the brushes it should help a lot. Brushless is the way to go in the long run though...

cmcclive 06.15.2009 12:09 PM

So, if I were to go brushless, can anyone recomend something close to stock? Does not have to be ROAR approved, I just don't want to go giving her to much power...
Is the VXL motor any good? is it near stock?

I checked on stock (17.5t) motors and I would rather not spend $75 to put a brushless motor in there consitering how little she would use it.

Any suggestions?
Thanks

Metallover 06.15.2009 01:32 PM

The performance of electric systems is greatly dependant on the batteries. If you run lipos and a brushed system, you can run a nimh pack or maybe even a123 with a brushless system and it won't be too fast.

Here is a chart showing brushed motor kvs. If you get a brushless motor of about the same kv it should have about the same performance. http://offshoreelectrics.com/motocalc_motor_table.htm

Also, if you gear down with a vxl motor, it should be about perfect for you. You can gear up and get bigger batteries if you ever feel the need for speed.

blueb8llz 06.15.2009 02:13 PM

im not too sure its the motor. my friends slash with a vxl motor and esc does the exact same thing. needs a push start...not all the time but most of the time. and he is running 3s lipos as well. i have a feeling it has something to do with the vxl esc. cogging maybe?

Slowkrawl 06.15.2009 02:27 PM

Quote:

Originally Posted by cmcclive (Post 295896)
So, if I were to go brushless, can anyone recomend something close to stock? Does not have to be ROAR approved, I just don't want to go giving her to much power...
Is the VXL motor any good? is it near stock?

I checked on stock (17.5t) motors and I would rather not spend $75 to put a brushless motor in there consitering how little she would use it.

Any suggestions?
Thanks

I have the vxl system in my sand rail, and while a lot of people prefer the castle systems it works great for me. A lot of people use the vxl motor with a castle esc.

What batteries do you have now? A 7 cell would probably be about right. I have a 3s lipo and she goes pretty good.

Maybe I just had a bad experience, but I put probably 4 or 5 brushed motors in my slash and could not keep them running. I could have just gone brushless in the first place. Also, if the truck is too fast for her you can program it into training mode, where you will get 50% power until she gets used to it.

Overdriven 06.15.2009 03:47 PM

I'd recommend training mode over gearing it for a slower top speed as that would give you more acceleration. The evader is already pretty light, and my nephews was a wheely machine and would understeer alot with more than half throttle on a vxl setup and geared about 35mph. You could always get a cheap hobbycity motor, or buy yourself a new one and give her your old one!

Metallover 06.15.2009 09:30 PM

Quote:

Originally Posted by blueb8llz (Post 295935)
im not too sure its the motor. my friends slash with a vxl motor and esc does the exact same thing. needs a push start...not all the time but most of the time. and he is running 3s lipos as well. i have a feeling it has something to do with the vxl esc. cogging maybe?

Brushed motors can't do the typical brushless cogging. What would cause "cogging" might be things such as a lazy motor, brush problems, or esc processing power.


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