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Drive A 380v/60hz Motor With Power Supply 380v/50hz


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#1 newbies2005

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Posted 29 June 2007 - 09:03 AM

Hello everybody!
I'm a newbie in the forum, find out many helpful thead. And here is my issue:
My client has a 380V/60Hz motor rating 7.5kW, but his supply is only 50Hz and the motor produce much heat. So we used VSD to control the motor. There're 2 way:
1. Use VSD to adjust frequency to 60Hz, change the gear ratio to keep output speed unchange.
2. Reduce the frequency and keep the gear ratio.
In my opinion, I choose 1st way, but is it right? And what is the effect of 2 ways? Is there any energy savings?
Thank you for help!

#2 marke

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Posted 29 June 2007 - 02:09 PM

Hello newbies2005

Welcome to the forum.

Set the drive up for a motor rated voltage of 380V and frequency of 60Hz, then set the speed to 50Hz if the load is designed to run at 50Hz speed.
This will reduce the flux in the iron to design flux and prevent the motor from heating up.
The problem with this aproach is that the effective KW rating of the motor will be reduced to 5/6 of 7.5KW
If the required shaft power at 50Hz is 7.5 KW, then you will need to run the motor at 60Hz and change the gear ratio.

Best regards,

#3 newbies2005

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Posted 19 July 2007 - 04:18 AM

Dear sir,
Thank you so much for read and answer my question.
I did it right in the way you advise: install the drive (ABB ACS350), set motor data to 380V/60Hz and working speed at 50Hz, not change the gear ratio. It seemed to be worked well.
But after that it appeared another trouble: The drive always displays alarm "A2026" after 2-3 min then fault "F0022" after 8-10 min then stop. In manual said:
"+ Intermediate circuit DC voltage is oscillating due to missing input power line phase or blown fuse.
+ Trip occurs when DC voltage ripple exceeds 14% of nominal DC voltage."
I also check the input cable and cable but everything's alright. For the DC bus, its comes from 532VDC to 545VDC, and ripple about 2-4V per second.
Another thing to be noticed that this is textile application, so the factory have 30 machines run at the same time. May be that is the reason?? And should I have to install a line choke in supply side to reduce the ripple? If I disable the protect function, will it affect to the capacitor bank and rectifier?
Many thank for any advice.

#4 Raslan

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Posted 09 September 2007 - 08:29 AM

QUOTE(newbies2005 @ Jul 19 2007, 07:18 AM) View Post

"+ Intermediate circuit DC voltage is oscillating due to missing input power line phase or blown fuse.
+ Trip occurs when DC voltage ripple exceeds 14% of nominal DC voltage."
I also check the input cable and cable but everything's alright. For the DC bus, its comes from 532VDC to 545VDC, and ripple about 2-4V per second.
Many thank for any advice.

Hi
I had experinced such a thing like that and here is one possible reason:
My case was: I had an elevator controlled by inverter and the DC bus when the motor is not running is about the same of your range i.e 550 V DC. in the driver which I was using, there was a monitoring function so I can keep my eyes opened over some parameters. So I watched the internal DC bus voltage and when I gave a command to the motor to run, the DC bus droped to 270 ~ 340 V DC which cuase to trip the driver with abormal laud motor.

Now for sure my problem is due to low power at the input of the inverter but what is going on?
All the fuses were ok! There was also phase sequnce monitor at the input of the whole control panel also it indecates that there is no phase loss or no worong in phase sequance. so??
I measured by the voltmeter the voltage between the phases (phase to phase measurement) then I have realized that there was one reading about 5 ~ 10 VAC while it should be 360 V AC. Then I have realized that there was one dublicated phase i.e. I have in my circuit 2 phases out of 3.

Hope this will help
Br,
Raslan





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