my esc got burn off around a month before , the connections were poor , but i wanto know the other possible reasons , becz im new to this hobby.

poor connections is one reason but , i would like to know whether the motor - battry combo , complimanting each other or not

i was using :

HobbyKing 12A BlueSeries Brushless Speed Controller
http://www.hobbyking.com/hobbyking/store/__11429__HobbyKing_12A_BlueSeries_Brushless_Speed_Controller.html


TURNIGY 2204-14T 19g Outrunner     
http://www.hobbyking.com/hobbyking/store/__6547__TURNIGY_2204_14T_19g_Outrunner.html


LIPO PP 7.4V 850 MAH 20 C

prop: 8x4

thank u ....!!

- saurab.

it seems to be a good combo however on site suggested esc is 10A but it could be a poor connection.

thanks Dharmik , im still waitig fr some more replies so that, i can confirmed n decide whether i should buy new esc or some else wid motor- battry .

this is the poor esc i have been through , the mystry 12 amp , go for turnigy , that is my opinion ..

You need to read up on choosing a proper (right) power system for the weight and type of the model you are using it on.  There are very good threads here on the subject. 

Of course things like bad soldering are outside of such discussions, but knowledge of basics is always a long term asset

@saurab.

Usually, the electric motors are made for certain RPM for each volt of potential difference. This is called the Kv rating. You would see motors marked 1000Kv, 2200Kv etc. Means a 1000Kv connected to a 12V batter would turn at 12000 RPM (well at least theoretically). Also theoretically, the motor tries to maintain the RPM irrespective of the prop.
Now a bigger prop would require more effort to turn thereby consuming more Amps. Since each ESC has a maximum capacity as far as AMPs are  concerned AND also each ESC has a maximum voltage rating. So the TWO most causes of failure would be the prop size (read amps) and cell count

thank u Anwar sir n pankaj , for such great info., now im reading more n more threads here in this site to hav some more knowledge n to save my money in future.....!!!

- saurab.