Fantastic Explanation. Every Oil well and Punch press uses a design D motor. Large Screw Header's as well. Many painful lessons of electrical maintenance engineers trying to replace a design D motor with new A or B. Many times it cant be done, even with an AC drive. Reciprocating loads, Heavy Fly-wheels, and Large startup torque prove the grave yard to the New Drives. Its Best to rewind the old dogs, or oversize drive and motor, with DB resistor, and overvoltage Supression Software in the Drive.
Rotor bar Inductance is greatly affected by the amount of iron around each bar. In the Design “A” rotor, the bars are close to the surface, meaning they are not as exposed to the magnetic effect provided by the iron. Therefore… less iron exposure…less bar inductance…less rotor bar impedance. Thus … higher current flow through each bar. As for the “B” rotor, each bar is exposed to MORE iron. In which case the inductive effect is opposite.
![Cody Johnson - I'm Gonna Love You (with Carrie Underwood) [Official Music Video]](http://i.ytimg.com/vi/yy9PuYMU29g/mqdefault.jpg)
Fantastic Explanation. Every Oil well and Punch press uses a design D motor. Large Screw Header's as well. Many painful lessons of electrical maintenance engineers trying to replace a design D motor with new A or B. Many times it cant be done, even with an AC drive. Reciprocating loads, Heavy Fly-wheels, and Large startup torque prove the grave yard to the New Drives. Its Best to rewind the old dogs, or oversize drive and motor, with DB resistor, and overvoltage Supression Software in the Drive.
super
great video zack solid lecture love your videos they help alot!
Thank you for a well done, informative, & easy to understand video. You would make a good school teacher or college professor.
Thanks a lot for watching!
why the inductance of class A is low and Class B is High?
Rotor bar Inductance is greatly affected by the amount of iron around each bar. In the Design “A” rotor, the bars are close to the surface, meaning they are not as exposed to the magnetic effect provided by the iron. Therefore… less iron exposure…less bar inductance…less rotor bar impedance. Thus … higher current flow through each bar. As for the “B” rotor, each bar is exposed to MORE iron. In which case the inductive effect is opposite.