You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Reply
 
Thread Tools Display Modes
Old January 11th, 2019, 06:43 AM   #16
Gene Bond
Member
United States

Gene Bond is offline
 
Join Date: May 2004
Location: Indianapolis, IN
Posts: 296
Quote:
240/480 50/60 HZ is odd. You have a factor 2 ratio between what I interpret as delta and star connection, not the usual factor 1.732.
Is it to be interpreted as that at 50 Hz, the motor should be connected to 240V delta, and at 60 Hz the motor should be connected at 480V star ?
Typically, NEMA motors are series or parallel connected for 480 or 240.

If the performance required of the pumps is adequate at 50hz, then you should be fine. If 60hz is required, then you're in trouble at 400v input to the vfd.
  Reply With Quote
Old January 11th, 2019, 07:49 AM   #17
JesperMP
Lifetime Supporting Member + Moderator
Denmark

JesperMP is offline
 
JesperMP's Avatar
 
Join Date: Feb 2003
Location: Copenhagen.
Posts: 13,499
It does not make any sense to me.
He has 400V supply available despite it is not a standard voltage in the US.
He then wants to connect a motor that is rated for the standard voltage 480V.
Why have a speciel 400V supply when the devices that are to be connected are rated for the standard 480V ??

he wrote "COPY EXACT PHILOSOPHY" of the Singapore plant. Was that interpreted as that he absolutely have to use 400V ?

And what about the 50/60Hz ? Is this an issue or a non-issue for the process ? Is this the reason why he wants to add a VFD ?
To copy the "philosophy" sounds not to me that everything must be exactly the same. It could be interpreted that you could adapt the hardware to achieve the same thing. Like changing a pump from x liters/h @ 50 Hz to a pump that provides the same x liter/h @ 60 Hz. Or changing the gearing on a conveyor. Or just changing V-belt pulleys. Having to add a VFD could be a solution if nothing simpler can achieve the same thing.

IMO it is not possible to answer any questions before all the information is out. That includes a photo of the name plate.
__________________
Jesper
See my profile interests for Q&A
  Reply With Quote
Old January 11th, 2019, 10:50 AM   #18
dwoodlock
Member
United States

dwoodlock is offline
 
dwoodlock's Avatar
 
Join Date: Nov 2012
Location: South Carolina
Posts: 414
Quote:
Originally Posted by skyfox View Post
Happy new year everyone.

This is more of a Electrical engineering question than a PLC one.

Can a Motor and a VFD that is rated for 240/480 60/50Hz operation be used on a system that has utility supply power of 3-Phase 400VAC? Customer is dictating 400VAC transformers for both their US and overseas factories? However, control cabinet electronics being used for powering the PLC, 24VDC Power Supplies etc., are running off from a 120 V step down from this very same 400 VAC transformer.

Can this be done or do I need to look for a VFD and a motor that is rated strictly for 400VAC use?

Thanks.
So for instance with us we use a lot of SEW eurodrive VFD's and their input voltage is usually a range "3x380-500V" @ "50-60hz". With a drive like this, you shouldn't have any issue supplying 400vac and controlling a motor rated for 480vac. I know that on some drives(Siemens), you will need to tell it what voltage it will be supplied, but most of these(SEW) that's not the case. If you exceeded the rating you would generate an overvoltage bus fault, and I expect the same would happen if you were under.

Seems odd they would specify 400vac unless the majority of the equipment will be in service outside the US, which may very well be the case.

Last edited by dwoodlock; January 11th, 2019 at 10:53 AM.
  Reply With Quote
Old January 11th, 2019, 09:11 PM   #19
sparkie
Lifetime Supporting Member
United States

sparkie is offline
 
Join Date: Nov 2014
Location: KS
Posts: 867
Quote:
Originally Posted by Aabeck View Post
I work on quire a few machines from Italy, Germany and China - where 400V is the norm.


These machines need a 480 - 400 3 transformer for their power. A 480V VFD fed 400V will fault for buss undervoltage. Frequently they are built without a control voltage transformer - 400V usually has a neutral that gives 200V and a DC power supply input is rated up to 250V. Rarely is there anything in the panel that is 120V.


Short answer = No. Tell the customer they need a transformer.
I seem to recall being told (yea I know it is vague) of a machine not running on 480 properly. The machine was shipped with a ~460 to 400V transformer and never ran properly until it was hooked up. This machine likely did have a servo drive, but not VFD per say. If you are being told the machine needs a 4xxV to 400V transformer, put it on one. I was assuming it was an entire machine and not just a motor.
  Reply With Quote
Old January 12th, 2019, 06:35 AM   #20
lfe
Member
France

lfe is offline
 
Join Date: Jun 2007
Location: Barcelona
Posts: 328
Quote:
Originally Posted by skyfox View Post
Happy new year everyone.

This is more of a Electrical engineering question than a PLC one.

Can a Motor and a VFD that is rated for 240/480 60/50Hz operation be used on a system that has utility supply power of 3-Phase 400VAC? Customer is dictating 400VAC transformers for both their US and overseas factories? However, control cabinet electronics being used for powering the PLC, 24VDC Power Supplies etc., are running off from a 120 V step down from this very same 400 VAC transformer.

Can this be done or do I need to look for a VFD and a motor that is rated strictly for 400VAC use?

Thanks.
A 480V 60Hz motor will work quite well with 400V 50 Hz because the lower voltage is compensated by the impedance reduction due to the lower frequency.

In contrast for the VFD you need one for 400V. It will not be difficult to find one since the most of the world works with 400V 50Hz, except in the US and its area of influence.
__________________
Suppanel HMI
  Reply With Quote
Old January 12th, 2019, 06:49 AM   #21
lfe
Member
France

lfe is offline
 
Join Date: Jun 2007
Location: Barcelona
Posts: 328


The specs plate of a standard three-phase induction motor. Note that the motor gives less power at 50Hz than at 60Hz and if it is going to be used at 50Hz you may have to select a slightly larger motor apart from calculating the gearbox for the 50Hz speed.
__________________
Suppanel HMI
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
Recent testing question mrtweaver LIVE PLC Questions And Answers 19 August 28th, 2009 03:14 PM
This is less of a PLC question and more an AutoCad Electrical Question Controls_Engineer79 LIVE PLC Questions And Answers 2 March 31st, 2009 01:47 PM
DH + Question kbradray LIVE PLC Questions And Answers 3 August 1st, 2008 02:02 PM
Integrator Business Question mjrx LIVE PLC Questions And Answers 3 April 12th, 2007 06:37 AM
How to Ask Questions The Smart Way Ken Roach LIVE PLC Questions And Answers 14 March 26th, 2007 09:12 AM


All times are GMT -5. The time now is 11:53 PM.


.