I'm posting here to help me solve my problem.
my project is designing a stepper motor driver , everythink is O.K but still one think freaking me out.
__a stepper motor is supposed tu run under a suply voltage higher tenfold or more than the rated voltage.
__my stepper motor power supply is 24V ( i do not have any information about my motor or it's rated voltage, it's a rare motor i did not found any datasheet so i have no idea about the rated current too).
__the resistance of a coil is 1.3Ω.
__so the amount of current that will flow through the winding is :
I=V/R=24/1.3=20A!! that's too much.
__so i have to limit the current to a constant value (better be the rated current but i don't know it if somebody tells me how can i calculate it, a will appreciate).
__just proposing to limit the current to 2A, then the resistor that i have to add is : 2=24/(R+1.3)--->R=(24-2.6)/2=10.7Ω that's fine BUT
the power dissipated as JOULE EFFECT (heat) is P=R*I²= 10.7*(2)² = 42.8 WATTS!!! that's toooooo much heat despite the use of POWER RESISTOR it's getting too hot.
__ so a friend of mine tells me to put a lightbulb that will dissipat that power but i don't see how.
if i put a light bulb(small resistance) it's will light up and will not limit much current.so i have to add a power resistor again en series and the current flowing it's big enough to make that power resistor to overheat.
i'm confused a little bit the idea of a lightbulb is good but i don't see how to use it please somebody give me a suggestions i will be thankfull.
that's my CIRCUIT here :
http://www.imagup.com/data/1122323635.html : sorry it's very big
download link :
http://www.mediafire.com/?66lssa171szqqaw
any information is welcome.
my project is designing a stepper motor driver , everythink is O.K but still one think freaking me out.
__a stepper motor is supposed tu run under a suply voltage higher tenfold or more than the rated voltage.
__my stepper motor power supply is 24V ( i do not have any information about my motor or it's rated voltage, it's a rare motor i did not found any datasheet so i have no idea about the rated current too).
__the resistance of a coil is 1.3Ω.
__so the amount of current that will flow through the winding is :
I=V/R=24/1.3=20A!! that's too much.
__so i have to limit the current to a constant value (better be the rated current but i don't know it if somebody tells me how can i calculate it, a will appreciate).
__just proposing to limit the current to 2A, then the resistor that i have to add is : 2=24/(R+1.3)--->R=(24-2.6)/2=10.7Ω that's fine BUT
the power dissipated as JOULE EFFECT (heat) is P=R*I²= 10.7*(2)² = 42.8 WATTS!!! that's toooooo much heat despite the use of POWER RESISTOR it's getting too hot.
__ so a friend of mine tells me to put a lightbulb that will dissipat that power but i don't see how.
if i put a light bulb(small resistance) it's will light up and will not limit much current.so i have to add a power resistor again en series and the current flowing it's big enough to make that power resistor to overheat.
i'm confused a little bit the idea of a lightbulb is good but i don't see how to use it please somebody give me a suggestions i will be thankfull.
that's my CIRCUIT here :
http://www.imagup.com/data/1122323635.html : sorry it's very big
download link :
http://www.mediafire.com/?66lssa171szqqaw
any information is welcome.