Setting timer from star contactor change to delta contactor

[weyland]

Hello everyone. I would like to know how many second we need to set on timer to change the star contactor to delta contactor. Is it depend on motor rating. let's say i have 10hp motor. so how many second should i set on timer? Thanks

 

[THE DUKE]

Hi It is more speed dependant you should have the motor to aprox 80% speed before changing into delta hope this helps, have a look at this link Star Delta Start Up Principles


Paul

 

[Knobhead]

It’s a case of suck it and see, as Paul said the change over needs to be about 80% of the running speed.

 

[weyland]

maybe different hp of motor have different time set. there must have a formula for it.

 

[JD6400]

Will probably get shot down in flames for tis post , but hey ho !
I always set them by ear , once it sounds just about run up then that is where i set it .:behead:

 

[Knobhead]

Contact the motor manufacturer. But it all comes down to the inertia of the load

 

[silva.foxx]

I've always clamped a line, started the motor and set to timer to when the amps start to drop after peak.

.

 

[Knobhead]

This is good reading but doesn’t directly answer your question. http://www.sari-energy.org/PageFiles/What_We_Do/activities/Afghan_Capacity_Building_Program_Aug_09/Skill_Based_Development_Program_on_Protection_Systems_11_2010/PRESENTATIONS/WEEK_1_ENGLISH/4.2.pdf

 

[weyland]

Thanks for the info, Tony.