my motor is cobalt 400, 9 turns. 30amp.
which is the best ESC?
I am a beginner  in aeromodeling. we have made an aeroplane but during its motor test the ESC exploded, esc was E SKY EMSOA

CAN ANYBODY HELP ME?

Welcome.. fellow Mallu 

The rule of thumb is a little higher (like 20%) than the motor rating, so 35A or 40A ESC. 

But since you mentioned an ESC explosion, can you post your full setup, including prop and battery ? 

Also, a "9 turn" Cobalt 400 motor is not showing up in online searches, can you verify and post the motor specs/model ?

   thank you for responding so soon. size of the propeller is 20-10. details of the motor are available at the links given below.           
    I need to know the manufacturer of the ESC as well as its cost .
       
        http://www.singahobby.com/images/electric/motor%20400%20cobalt.jpg
        www.maxxprod.com/mpi/mpi-26a.html

20-10 prop ? Are you measuring in centimeters instead of inches ?  If it is in inches, that is an unusually large prop.

MPI has brushed ESCs that suits your setup, and there are many other brands also. 

But before that, you may want to consider other options. If you are on a lipo battery, you may want to consider moving to a brushless setup, instead of spending on a brushed ESC.  What is the weight of the plane you are putting this on ?

Before making an informed decision, the prop size, battery capacity/type and weight and type of the plane have to be verified.  Otherwise you may again run into costly power issues.

i am using lipo battery  YUNTONG, 30C,1000mAh

Is that a 2cell lipo or a 3cell lipo ?

i am using lipo battery  YUNTONG, 30C,1000mAh. prop is 20 cm in length. weight of plane is about 1.3 kg. I have already bought a brushed motor.

it is a 3 cell lipo.

Thank you for forwarding the details.  So your prop is OK, it is about an 8 inch prop (8x4).

It is known that 3s lipos are too much for many brushed setups.  I am unable to find the specs for your exact motor since you mentioned "9 turns", and all the ones I can find are "14 turns", "11 turns" etc.

ACTUALLY IT IS 11 TURNS

Looking at the specs of the on the MPI site for the PMX4011  one can assume that the  RPM of the 9 turns if at all it  exists is higher than 16100 further the recc prop for the PMX 4011 itself is 6 x4  hence for a higher RPM motor it should be smaller if not the same . Hence it is obvious that  with a 8x 4 the amps draw has far exceeded the max amps level of the ESC .
I am surprised that the motor has not cooked itself with 11.1V and an 8 x 4 prop.
Are you sure the damage is only to the ESC  
The Max amp of this motor is 23.5 amps hence a 30 amp Li ESC is a must  something like the GWS ICS 600Li.
http://www.gwsus.com/english/product/speedcontroller/600.htm


Anwar  brushed motors can work with 3 S Lipo provided the ESC is capable of handling that voltage , like GWS have Li series ESC which can work with 3 S Lipos .
BTW I agree with Anwar rather than Invest ina 30 amp brushed ESC which will cost around Rs 1400 I would rather buy a  bruhsless set up which might work out cheaper.

sai

Quote from: rcforall on October 20, 2009, 07:32:46 PM
Anwar  brushed motors can work with 3 S Lipo provided the ESC is capable of handling that voltage , like GWS have Li series ESC which can work with 3 S Lipos .

Yep, that is why I was careful in saying "many".  Wish Avinash had got in touch with us earlier, since he could have gotten a brushless setup (as he had already gone for a 3s lipo etc). 

Sai - Can you propose both a brushed esc and a brushless combo with prices for him, so that he can make a choice ?

OUR PLANE WEIGH 1.3 KG, WITH WING SPAN 1.5M, LENGTH IS 71 CM.
 CAN OUR PLANE FLY WITH PROPELLER 6*4.?

 CAN WE USE 8*4 PROPELLER ?,WITH  
CELL -YUNTONG, 30C,1000mAh, 3S
motor is cobalt 400, 11 turns. 30amp.
FOR THIS WHAT SHOULD BE THE CAPACITY OF ESC?

Dear Avinash,

If the motor is capable of 30amps, then atleast the ESC should be 1.2 times the max amp or about 40amps to begin with you can also go in 50/60amp

ESC selection is not the only question asked.

Avinash - There are many threads here on electric power selection.  At a high level, here is roughly how it works.

1. Weight of the model determines the "watt"age of the motor.

2. Aircraft type (and in some way the flying style) determines the KV rating of the motor. With wattage and KV rating, you can pick a motor.

3. KV rating largely influences the prop selection.

4. Motor (and the prop) determines the amps drawn, and this determines ESC selection.

5. Battery is determined primarily by ESC selection.

People like Saju can add more (or make amendments).

I am, admittedly, a newbie to electrics and find that there is not much (useful) information available from most sellers of motors.

What I would like to see included is, at least a link to obtain the following information:

Wattage
KV rating
Graphs of current drain vs Voltage (2s, 3s etc) vs prop size

This would go a long way in helping us make a choice suitable  for any specific need/requirement.

I think this post is in the wrong place.

It could be in "selection of motor and ESC" but the foamy bit might be misleading.

Anwar, help steer it to where it belongs!

No mention of "foamy" anywhere in this thread. Sushil bhai... kindly clarify 

BTW, KV ratings of most motors are highly publicised, and so is wattage of many.  The prop versus current drain charts are also available, but not as frequently.

I do see that direct questions asked by Avinash are not answered yet, like "Can our plane fly with a 6x4 prop?".  

Quote from: avinash.tutu on October 22, 2009, 12:18:57 PM
OUR PLANE WEIGH 1.3 KG, WITH WING SPAN 1.5M, LENGTH IS 71 CM.
 CAN OUR PLANE FLY WITH PROPELLER 6*4.?

 CAN WE USE 8*4 PROPELLER ?,WITH  
CELL -YUNTONG, 30C,1000mAh, 3S
motor is cobalt 400, 11 turns. 30amp.
FOR THIS WHAT SHOULD BE THE CAPACITY OF ESC?

Sure looks flyable on a 6 x 4 as by proportions it looks like a glider

PROVIDED :

1) the wing is designed to be a glider
2) the motor ref is right and as per specs
3) the motor does not have any internal damages  already (  I strongly suspect this ) . The reason I say this is because the motor specs clearly says 7-8 cells ( hence 8.4 ~ 9.6 V going with Nimh ) and test voltage of 8 V .
http://www.maxxprod.com/mpi/mpi-26a.html

hence in my opinion the motor should be fried by now OR at least have had some internal coil damage .

Sai

Thank you Sai for your information. we have checked the motor by connecting directly to the battery, and its working smoothly.

So looks like what you need is a 40A (or 35A) brushed ESC that supports 3s lipos, and a 6x4 prop.

Sorry for not getting here earlier...
Could I know what is the area of the wing,
chord length of the wing,
type of flying the model is built for ... like: trainer or mildly aerobatic or fully aerobatic, or 3D, or pylon racing etc.

Also the make of the prop (6x4 or 8x4 ?)?

Saju

Quote from: sushil_anand on October 22, 2009, 04:23:11 PM
I am, admittedly, a newbie to electrics and find that there is not much (useful) information available from most sellers of motors.

What I would like to see included is, at least a link to obtain the following information:

Wattage
KV rating
Graphs of current drain vs Voltage (2s, 3s etc) vs prop size

This would go a long way in helping us make a choice suitable  for any specific need/requirement.

These set of docs from Sai for the motors he sells should help.

http://www.rcindia.org/electric-power/full-datasheets-of-all-rcforall-motors/

hai saju....

its  our first plane
wing area area 170*17
length 71cm
our plane  don't have aileron
prop 8*4
we don't know in which category it falls 
how can we differentiate planes by seeing its structure?

seriously a pic would help   

subbu