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jeetbuz
01-10-2011, 06:38 PM
i am using 4 motors from nex

http://www.nex-robotics.com/products/motors-and-accessories/dc-motors/200-rpm-side-shaft-lm-series-dc-encoder-motor.html

to drive a robot of weight approx 20kg on 20 degree incline.

which motor driver and battery to use .(max 24v)

vikas
01-10-2011, 08:48 PM
Read this -

http://www.societyofrobots.com/mechanics_dynamics.shtml

Should answer all your questions ...

jeetbuz
01-10-2011, 09:22 PM
thanks for the prompt reply

i have calculated my torque requirement.
what i need is a good circuit for high current motor driver .
would a lead acid battery 12v 7.2ah work with these motor for long??
according to the calculator on the site it will be dead in less than 18 min.

i need atleast half hour.

vikas
01-10-2011, 09:52 PM
I never recommend Lead Acid for robot ... Just too damn heavy and increases the torque requirements. Use Lipo they are light and easy to use.

Is it a competition , if competition post link ... or some other professional robot.

jeetbuz
01-11-2011, 02:34 AM
okay
can u give me circuit diagram of a 15/20A , 24 v or above motor driver .
it is costly on nex-robotics.
thank you

vikas
01-11-2011, 08:28 PM
Well if you are on a budget look into relay based motor driver ...

Something like
http://www.kroell.it/pwm_motor_driver.html

jeetbuz
01-22-2011, 04:01 PM
thank you vikas.
but can u give me mosfet circuit for 12v 10A dc motor controller.
It will help me a lot

MohitM
01-22-2011, 05:28 PM
About the motor:
Does it have to be speed controlled using PWM?
Does it have to be reversed?

vikas
01-22-2011, 05:30 PM
He he here you go ... Pick the idea from this

http://www.picbasic.co.uk/forum/attachment.php?attachmentid=2517&d=1208532602&t.jpg

Do two of these and you have a cheap powerful bridge !!!

jeetbuz
01-23-2011, 08:52 PM
@vikas
great thank you

@mohit
yes both.

jeetbuz
01-24-2011, 07:13 PM
can i use 2 of these controller
http://www.ikalogic.com/h_bridge.php
to drive a 8A motor:p

vikas
01-24-2011, 07:33 PM
15 - 20 A with 24 V :)

No Way !!!

The Collector Current DC is 5 A ( safe ) , While PWM its 8 A so nowhere what you want.

jeetbuz
01-25-2011, 11:06 PM
but can i use a power mosfet to make a bridge circuit.
if yes can i get one in LRM.

vikas
01-26-2011, 10:04 AM
You can get most stuff in LRM , but judging from your current level of expertize i would recommend building a cheap relay based one. Easy to debug and high power.

P and N channel pair can cross Rs 100 easily + you need other transistors and extreme care while building a Mosfet hbridge ( cannot be manhandled like transistors ). Anyhow its better you build something now ....