Motor confusion, seller shows different specs.

Started by naatumach, June 21, 2011, 08:41:52 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

naatumach

Disclaimer: I am not trying to impugn anyone, i am only curious.
RCforall sells 'Brushless 2805/1400KV' motor with specifications link http://cgi.ebay.in/BRUSHLESS-COMBO-PLANES-UPTO-500-GMS-/150606265331?pt=LH_DefaultDomain_203&hash=item2310d53bf3
Weight 32g
KV(rpm/v) 1400
Max Power 120W
Battery 2lipo
Prop 6x4/7x3
ESC 18AMP
Motor size CF2805-14
   
And on the same page they recommend
RCFORALL BRUSHLESS MOTOR COMBO 2805 SERIES COMBO BL MOTOR + ESC20AMP+PROP 9 INCH OR 8 INCH

On the dys website link http://www.dys.hk/ProductShow.asp?ID=212
They say
Weight 32g
KV(rpm/v) 2840
Max Power 120W
Battery 2lipo
Prop 6x4/7x3
ESC 30AMP
Motor size CF2805-14

Can someone please clarify, what i am missing here?

Regards
Vaibhav
Disclaimer: I am not trying to impugn anyone, i am only curious.
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

sundaram

Quote from: naatumach on June 21, 2011, 08:41:52 AM
KV(rpm/v) 1400

KV(rpm/v) 2840


The difference is there.

KV 2805 is suitable for only upto max prop dia 7x3. that too with 2S cells. Recomended ESC is 30 Amps. If you use 3S you will have to use 4x4 prop though not recomended since it will cross the rated watage of the motor.

The same motor is also avaiable in 1400 KV which you can use up to 9x4 prop with 3S cells. but it consumes less than 20 Amps.

Both are 120 Watts since it is recomended to use 2S for the KV 2805 and 3S for the KV 1400. KV 2805 draws more amps the KV 1400 draws lesser amps but the wattage is same for both (V x I turns out to be the same)

First specs at the Rcforall ebay stating only 2S and 6x4/7x3 prop for a 1400KV is a typo. it should be 3S and 9x4.

anwar

Hangar : Please see my introduction.
RC India forum and me : About this forum.

naatumach

Quote from: anwar on June 21, 2011, 09:27:06 AM
Here is the original thread and response from Sai :

http://www.rcindia.org/electric-power/kv-confusion/
Sir
I did read that before but i really didnt understand the concept, until i read sundaram sir's explanation..
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.