Need Help Guys, Design Idea help

[richardv24]

Hi Guys,

Ended up on this forum looking for help. Read through a few things and it seems really fun and interesting. Not sure if I am posting in the right section

Here is my situation.

I have projects where I get many motors (lets say anywhere from 8-100) hooked to a single power supply. The problem is when the motors all turn on at the same time, I get a huge in-rush current that trips the breakers. I was wondering if there would be some way using something like a PCB that would take the supply power and split it to each 460 volt motor but have each motor turn on within 1 second from each other.

So I need something so that all the motors turn on separately so there would be no HUGE in-rush current.

Thanks for any help.

[kellys_eye]

A properly designed PSU would cater for the inrush. What voltage/current rating are the motors?

[richardv24]

Thanks for responding.

The voltage is 480 and the inrush current is about 120 amps for a very short duration. I would appreciate being guided to some kind of an example that does something like this.

Thanks again

[Sch3mat1c]

Supply all the motors from contactors; sequence the contactors with time-delay relays.

Tim

[CWB]

"The voltage is 480 and the inrush current is about 120 amps for a very short duration"

is that total current or for each motor ?

yep ... a sequenced contactor system is the best bet .
if you want to save a lot of headaches in design there are industrial time delay controllers/contactors that can send a trigger to the next contactor unit down the line .
the time delay before triggering the next unit is essential ... each motor has to come up to speed in order for the current draw to drop .

you mentioned 8 to 100 motors ... be prepared to thin down your wallet .