Is there any way to reduce the starting current of a motor since it will cause trip/blackout during start? The start configuration for the motor is direct-on-line (DOL).Need suggestion.Thanks!

 

You can momentarily switch in a power resistor or inductor in series with the motor to limit the starting current and then switch it out (short across it) when the motor has finished its start.

 

If this is a typical 3-phase AC induction motor with stator windings configurable in Star or Delta then a useful technique is the star/start-delta/run method. This requires some control hardware - as will any soft starting method.

 

Is there any way to reduce the starting current of a motor since it will cause trip/blackout during start? The start configuration for the motor is direct-on-line (DOL).Need suggestion.Thanks!

what's tripping, your overcurrent or overload? Does the load require a softstart scheme? Are you hooked into inadequate supply?

 

I just got the datasheet from the supplier. The starting current of the motor is high. 390A. The start configuration of the motor is DOL. So, is there any way that I can reduce it? By the way, is there any effect to the motor if the starting current is high?

 

what's tripping, your overcurrent or overload? Does the load require a softstart scheme? Are you hooked into inadequate supply?

Overcurrent tripped.

 

Check out this soft start control--they are available for even higher currents, but this seems to be the largest handled by Grainger--the line current passes through antiparallel SCRs that are phased on gradually to reduce starting surge--75A is the full load current--during starting, the current will be roughly 150A. To reduce conduction losses, some units have a contactor that bypasses the SCRs after starting.

http://www.grainger.com/Grainger/SCHNEIDER-ELECTRIC-Soft-Start-6VMA0?Pid=search

 

I just got the datasheet from the supplier. The starting current of the motor is high. 390A. The start configuration of the motor is DOL. So, is there any way that I can reduce it? By the way, is there any effect to the motor if the starting current is high?

I don't want to sound like a grumpy old guy but a 390amp motor is an expensive professional device and the way it is started, wired, safely fused and run should all have been handled by a properly trained professional.

 

You can momentarily switch in a power resistor or inductor in series with the motor to limit the starting current and then switch it out (short across it) when the motor has finished its start.

can you please explain this bit more, if possible. thanks..

 

can you please explain this bit more, if possible. thanks..

If you don't understand that then you should not be messing with this motor and those currents.

See RB's post. You could easily kill yourself or someone else. Even a whole group of people or cost you company millions of US dollars in a burned down building and / or lost business.

Get someone that knows exactly what they are doing to install this motor for you. A motor of that size must cost a lot of money. It is not going to cost much more to have it installed properly.

While we have some extremely talented and helpful people on this forum. a hobby forum is no place to seek advice of this type. No one is on location to see the exact situation.

We have a saying "Penny wise and pound foolish".

It means you are trying to save a small amount of money while risking a great deal of money.

 

If you don't understand that then you should not be messing with this motor and those currents.

See RB's post. You could easily kill yourself or someone else. Even a whole group of people or cost you company millions of US dollars in a burned down building and / or lost business.

Get someone that knows exactly what they are doing to install this motor for you. A motor of that size must cost a lot of money. It is not going to cost much more to have it installed properly.

While we have some extremely talented and helpful people on this forum. a hobby forum is no place to seek advice of this type. No one is on location to see the exact situation.

We have a saying "Penny wise and pound foolish".

It means you are trying to save a small amount of money while risking a great deal of money.

thanks for your advice mate. i m not trying to burn down a place or people... i just ask this because i thought its interesting to know. thanks anyway.

 

show the motor + the power supply.

 

Also, remember that reduced current=reduced torque. What kind of load is on the motor? Does it require full starting torque of the motor?