[charaf]

please i need more formation or tutorial about
Braking AC motor by DC Injection

[ماجد عباس محمد]

يمكنك للتفاصيل وضع سؤالك فى قسم الهندسة الكهربية لكن باختصار فإن وضع تيار مستمر فى القلب المتحرك لموتور متردد أشبه بجعله مغناطيس دائم ثابت مما يجعله يجذب الجزء الثابت مسببا الفرملة

[charaf]

thanks sir but i need more
for exmple what is the voltage required and current
thanks

[ماجد عباس محمد]

I know but it depends greatly on the motor data so probably They will be able to provide the information you need, however a google search gave this for theory
http://en.wikipedia.org/wiki/DC_injection_braking
and this from a manufacturer of such devices
http://www.softstartuk.com/dc-injection-brakes.html
so , I think the device is programmable as current source in some way to provide the dc current that the motor normally use to run because dc will not see the inductance tha ac will and an external limiter here must be used

[charaf]

thanks sir but i want to make by my self that's why i wanted to know the voltage and current even brak ac motor single phase
please help me

[ماجد عباس محمد]

What I can say is it is a current controll device either by thyrestor control or mosfet
You may start with a measure to the back emf generated while the motor stalls and provide a dc voltage starting from that level
I only delt with DC motors and its drivers, for ac motors I got the inverters to provide speed control as well as breaking and other controls needed
If I find any other material on that subjet I will let you know

Trying with low voltage and increasing it gradually while keeping an eye on the current up to the motor's full load value and a littile more will never hurt anything

[charaf]

ok sir thanks so much

[ماجد عباس محمد]

Ok then Good Luck, if I cah help pls let me know