star-delta or DOL

Maybe Ambani's Consultant wrote a 1-line spec. "All DOL". Huge Power system--OK-- every application will start-maybe 6 times inrush current.

Also avoided human errors---when to switch over to Delta. Also minimised maintenance of sparking brushes. And enabled easy/Cheap remote auto start/stop/start on computer control.

Pune-- Small scale -- limited power connection.

Maybe the machine starts on no load.

So preferred S-D

MM

hi

star delta starter is basically used to smoth start of the motor such that the starting of the motor do not affect the other runnig equipements of the same bus, where in motor will initially run as lower voltage i.e. 415/1.73 and then switch over to 415 v.

in this starter when motor initally run with star connection, it run with slower speed and torque to output LPM and pressure of the fluid will be also less after putting in delta motor will run with full speed and torque and supply fluid with pressure, now in refinary it is required that as soon as we switch the motor ON, fluid mush provide with its rated pressure in further prosesses, so always DOL is used in such kind of requirements,

best regards

divyesh patel

Safety Hazard is a main concern in the selection of DOL in refinery. In star/delta, there are many chances of small spark which may burn whole refinery. Have you heard of fire incident in Delhi bring spec of FRLS into Cables?

In oil industry the spark and fire hazard is the main concern second as mentioned by other gentleman the inrush current and voltage dip when several motors are operating on the same bus in a process industry will play a dirty game when you start a large motor on Star delta starter available and used for general application.in fact the electrical generators for oil industry are ordered with Air start motors instead of Electrical start motors and special silencer fitted with Spark arresters are installed to take of Fire hazard.

crm

In large plants having their own substations of 33KV and above with larger power of the order of 10MVA+ normally all motors are on DOL as the motor starting will not cause any system disturbance or voltage drops that can cause other running motors to pull out and cause certain equipments sensitive to voltage to malfunction.This plant supply may be insufficient and hence star Delta is used.Normally in all paper , cement,Refineries dol is used.

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