can anyone tell me how to calculate the braking torque developed through dc injection braking in induction motors?

 

I don't have the formula. However, according to my old VFD training material (partly derived from Industry textbooks), the rules-of-thumb include:

- Idc can be up to 2-3 times nominal
- Brake time proportional to Idc squared

 

DC current calculation using two or three of the stator leads for either wye or delta windings as well as theory was presented to List about Dec
01 thru Jan 02. Search archive for:

ENGR: AC Motor Braking.

or

APPS: Induction Motor Braking.

Regards,
Phil Corso, PE
(Boca Raton, FL)

 

Follow this link:

"http://www.abb-drives.com/StdDrives...iles/products/ElectricalBrakingTechGuide8.pdf":http://www.abb-drives.com/StdDrives...iles/products/ElectricalBrakingTechGuide8.pdf

 

Are you still interested in braking AC motors by injecting a direct current? You can find formulas on the web page emp.etfos.hr/ES/Default.htm by clicking the name next to the appropriate title.