Answer / rakesh patel

Formula: K=
R.V/1.73R.A
where R.V=Rotor
voltage ,
R.A=Rotor
Current ,
K=constant ,
than
1step=1.40K ,
2step=.35K ,
3step=.15K ,
4step=.08K now
put the data and
get your ans.

Answer / purushottam

This motor is used for both purpose as it is used in 15 Ton
EOT crane main Hoisting / Lowering application. External
resistance used for speed control & for High Starting Torque
both.

Answer / p.veerapandian

Can u tell the application of the inserting external
resistance in the rotor circuit for speed variation or
starting with heavy torque application

Answer / prashant

All hoist and travel drives in EOT cranes, or any equipment for that matter, that use Slip Ring Induction Motors and need speed variation use these resistance boxes. The method of calculating steps in external resistance is absolutely correct as told in 1st answer.

Answer / gulzar ahmad naikoo

There is thumb Rule for percentage of cutting resistance.1st step full calculated resistance,2nd 50% of total,3rd,50% of 2nd,4rh 50% of 3rd, and so on.

Answer / prakash gidde

Mr. Rakesh, Pl explain how many % of external resistance need to cut en each step during operation of slip sing motor? also pl explain on which bases u considered 1.4, 0.35, 0.15 & .08 value for calculation of step wise resistance.
cutting of resistance should be on application of motor where to we are going to use & lifting load capacity. Also its depend on which type of resistance we are using -- SS punch plate grid / punch wire grid/ oil merge/ liquid water resistance.

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