Starters for HT Motors ( 1.1 KV,800KW)

Depending on the power supply source,DOL starting without load may be possible.As motor of this capacity and depending on the type of motor chosen, the starting current can be more than 6 times the normal running current and it may take 15 or more seconds to reach full speed.This will cause the source supply to trip.

Auto transformers with several steps can be used.Kindly see what I have just writen for one asking about 6.6KV starter.

My question here is why do you select 1.1KV instead of more common 3.3 and 6.6KV motors where component/parts are easier to obtain.The conductor in 1.1 KV is still very large with relatively thin insulation ( slightly thicker than 415V ) and it should more expensive than 3.3 KV.You have to use 6.6Kv switchgears even for 1.1KV motor.

Regards,

Khor.

Pl. see my reply to a smilar post.It is just not a casual or there is any thmb rule.It has to be worked out with details.

VFD is good choice.

- MS

It seems that voltage is not common or standard ,in my view you may rewind motor to 3.3KV and use either soft starter if any constraint for funds else use Variable speed drive -benefits are enormous.

You can use VFD .But it will be costly .

If you are concerned about reducing the starting current , you can go for Softstarters.This is a power electronic Device , which is Thyristor controlled.

DOL is the best choice if your system can withstand starting KVA without extreme voltage drop.Starting current is a design function .only its duration can be changed by starters.It is very essential to specify a correct motor.Many times this aspect is left to driven equipment suppliers who just supply something they are always used to.Low starting current motors limiting to even 3.5PU can be procured but expensive.Load acceleartion time need to be calculated which has to be within the locked rotor withstand time of the motor.Without doing all this simply advising this starter or that is no way provide a correct solution.