how to find out which 1 is gone

[dodgydiy]

you should be drawing 30 to 40 amps on a 600w motor if propped correctly, thats pretty close to the 55A limit of that battery, but to be drawing only six amps, if the motor is running smoothly it has to be a speedo problem

[zoaman]

update. I have got my hands on a peak atlas lcr40.well it done a self test and it comes out
15khz and 0.2ohms.so can any body shed any light.is this correct as its quoted a being 0.053ohms. ???

[Great_Thark]

would of course help if you told us what you are testing!

I presume its the motor, is that reading the dc resistance or the reactance at 15khz both are in ohms.

the quoted resistance will be dc. Reactance changes with frequency and changes again in a motor once it is spinning, what you are measuring is static reactance of the winding which is fairly meaningless unless you have a known good motor to compare. The odds are your esc will be switching at 8khz

If you want to be able to diagnose this stuff in the future I suggest you trawl the net for some basic electronics stuff, really need the grounding to understand how it all works and your obviously interested.

In the meantime to get you in the air (winds forecast to die down next week woo hoo)I will stick to my earlier guess of a duff esc. The ones they include in RTF and ARTF tend to be pretty poor.