RC India
Welcome Guest, please login or register.
 
Pages: [1]   Go Down
0 Members and 1 Guest are viewing this topic. Topic Tools Topic Tools 
Read
« on: August 07, 2009, 10:44:58 AM »
TEJASCOOL007
Plane Lover
Active Member

**

Reputation Power: 2 
TEJASCOOL007 has no influence.
Offline Offline

City: KALYAN
State: Maharashtra
RC Skills: Beginner
Posts: 71
Join Date: May, 2009




hi i m tejas,
i want to ask a query that,
   since i have used brushed motor in my first design n supplied 12 volts .
      but if i use BRUSHLESS motor at 6 volts instead of it then will the motor produce same pull 
      sufficient for the take off  Huh?Huh?Huh?? Undecided
   waiting for ur responses......!!!!
                                                                              regards
                                                                                     
Logged

struggle is the only key to become airbone..!!!
 

Read
« Reply #1 on: August 07, 2009, 12:01:48 PM »
mpsaju
Plane Lover
Senior Member

***

Reputation Power: 2 
mpsaju has no influence.
Offline Offline

City: Chennai
State: Tamil Nadu
RC Skills: Intermediate
Posts: 114
Join Date: Mar, 2009



Hi Tejas

Welcome to the forum. My name is Saju. Well on to your query:

"since i have used brushed motor in my first design n supplied 12 volts .
      but if i use BRUSHLESS motor at 6 volts instead of it then will the motor produce same pull 
      sufficient for the take off  ? "

In a brushed system, there is a mechanical commutator which aids in changing poles for the rotor (coils) to rotate in the magnetic field created by a set of permanent magnets (which forms the stator). In a brushless motor, the coils are stationary (stator) and the magnets are rotating (rotor). The commutation is acheived by electronic means (the Electronic speed control... or ESC in short). The freqeuency of changing poles determines the rpm of the motor in both cases. The mechanical system of commutation is less efficient because as the brushes rub over the commutator there are sparks generated and also because of contact resistance of the brush on the commutator not being consistant since there is mechanical movement. There is also erosion of the brushes and the commutator and therefore performance deteriorates from time to time... leading to maintenance requirements in the form of replacement of brushes and cleaning of the commutator. All this is avoided in electronic commutation and therefore makes it more efficient. Moreover the speed is determined by the electronics  and therefore is more consistant. Hence even at low voltages a brushless motor will give better performance than a brushed motor.

When it comes to RC planes, we have other factors as well to take care-of. In a small model to reduce weight we will generally have one battery which has the duty of powering the BLDC (brushless dc) motor, the radio (requires  only 4.8v to 5v), and servo actuators (one for each control function... generally elevator, rudder, and throttle) besides other optional devices one may load on the model. The batterries used are nowadays, what we call as LIPOS (Lithium ion polymer), which have the same chemistry as the cells used in mobile phones and laptops. You would do well to search the internet for a complete understanding of LIPOS. To cut the story short, the ESC will get connected directly to the LIPO (either 7.4v or 11.1 v etc multiples of 3.7v) and the ESC in turn will reduce and supply 4.8v to power the radio and thru the radio the servos. It is generally not a good idea to reduce the voltage below 7.4v at which point the esc will stop operating the motor and will give you sufficient power to land the plane.

I said too much... please excuse me for the long explanation... but I thought atleast this much is in order.

Any further doubts are welcome

Saju
Logged

Happy Flying


Saju
 

Read
« Reply #2 on: August 07, 2009, 03:16:23 PM »
Pikle6
Plane Lover
Forum Hero

*****

Reputation Power: 13 
Pikle6 has no influence.
Offline Offline

City: Navi Mumbai
State: Maharashtra
RC Skills: Beginner
Posts: 1050
Join Date: Apr, 2009

VTOL - Vertical Take Off & Landing



some info on how to connect the stuff (bl motor esc batt etc etc)

http://www.ampaviators.com/images/stories/articles/artimages/0402071.jpg
Does BRUSHLESS give more efficiency at low voltages.???


http://www.ampaviators.com/index.php?option=com_content&task=view&id=50&Itemid=27
Logged

E.V.Subramanian
Yak55|EasyFly Glider 1.9m|Skyfun|Easystar II|Quad Talon V2|Mini Saturn
 

Pages: [1]   Go Up
Jump to:  

Related Topics
Subject Started by Replies Views Last post
how to increase efficiency of a self made hotwire cutter
Tools, Materials and Building Techniques
roby 9 6384 Last post December 20, 2013, 02:52:52 PM
by shobhit17
want cc3d and quad motors of high efficiency
Wanted
sahil007 2 1301 Last post November 04, 2015, 11:08:12 PM
by sahil007
Automated RC Motor Efficiency Tester
RC General Topics
lastRites 0 1304 Last post April 07, 2016, 03:58:19 PM
by lastRites
Best brushless motor to give maximum thrust
Multirotors
Shubham954 19 5860 Last post January 24, 2021, 06:54:35 PM
by rathode
Rewinded a Emax 2805 2840kv motor into lower kv & higher efficiency
Electric Power
Susavan 2 1917 Last post December 07, 2019, 07:10:15 PM
by pnkyjs