Join TSR now and get all your revision questions answeredSign up now
    • Thread Starter
    Offline

    0
    ReputationRep:
    Can anybody explain star delta to me please? I understand that large motors are started by initiating in a star connection at a reduced voltage then switch over to delta but what is the reason?

    Thanks
    Offline

    1
    ReputationRep:
    Think of star as a softer way of starting a motor. Less current and less torque until the motor is up to speed because it reduces the chance of damaging a machine by putting it under high load from idle, then switch to delta when its at or near to operating speed. Hope it helps.
    • Thread Starter
    Offline

    0
    ReputationRep:
    Thanks for your reply but what I was looking for was the reason a machine can't be started in delta? Any help would be appreciated!

    (Original post by Popeye89)
    Think of star as a softer way of starting a motor. Less current and less torque until the motor is up to speed because it reduces the chance of damaging a machine by putting it under high load from idle, then switch to delta when its at or near to operating speed. Hope it helps.
    Offline

    1
    ReputationRep:
    Starting in star reduces the chance of damaging a machine. Say for example you have a 5KVA machine, starting in star will enable you to slowly build up to that where delta will ask for the whole lot straight away. Asking for all of it right away can cause excess wear and damage whereas easing it up to speed is better for the machine and the motor.
 
 
 
Poll
How are you feeling about your A-level results?
Useful resources

Features

Blinkered horse

Take off your BTEC blinkers

Find out the truth behind the BTEC myths.

Polling station sign

BTEC essentials

What you really need to know about studying BTEC.

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.