Answer / gurusaran

Double delta connection is used to achieve reduced voltage
during start up of a motor by changing a delta connected
winding from parallel groups to series groups.This is termed
as "double delta connection" because the delta winding is
connected in series during start up and the same is connected
in parallel during running condition with the help of a part
winding starter.Since all winding's are connected in starting
as well as running conditions the amount of heat generated is
not so severe.

last 5 year rrb allahabad junior engg electrial engg question paper

0 Answers   RRB,

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what is main reason for grid earthing for any industry

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in dc shunt motor if armature wdg is open then

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There are two nos of 33Kv/11Kv 5MVA transformers conecting through HT cable from substation having metering at substation itself.One transformer used at a time another remains stand by.Further 11 nos of 11Kv/440V transformers are attached on it and each transformer is having its own Power factor correction panel.Now one 33/11Kv transformer at no load condition/Stand by condition is having power factor in leading side upto 0.21 and while when another tranformer at same situation have power factor in lagging 0.42. Now one thing is clear that transformer one is having 1.5 Km long 33kv cable due to that PF goes in leading side and another is having only 250 mtr length remains him lagging. Now i want to know that how i can maintain the Power factor at no load/ stand by position though both are behaving in seperate manner.

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whether fibre optic cable in high voltage earth conductor is used for protection circuits

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why autotransformers are not safe for supplying low voltage from a high voltage source?

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why Power transmssion voltages are as 11kV,33kV,66kV,220kV and so on only?

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i want to run 11kv star connected motor in 6.6kv with delta connected throught inverter, is it possible?

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What is thyristor?

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in our sub station why we step down firstly 33kv\11kv then 11kv to 430v. can we direct step down 33v to 430.v.

18 Answers   Eaton, Siemens,

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