VFD on 230V 50Hz single-phase power source to drive 400V 50Hz three-phase IM load 2

[che12345]

Dear Sir,
Utility power source: 230V 50Hz single-phase. Load is a centrifugal water pump IM rated 400V 50Hz 11kW 22A three-phase. Wish to regulate the pump speed by using a VFD.
The problems are:
a) a VFD rated for 230V single-phase input is unable to produce 400V three-phase output,
b) unable to source a VFD rated for 400V 50Hz single-phase input,
c) the IM is 400V 50Hz three-phase existing at site. No intention to replace it.
Please advise possible solution.
Che Kuan Yau (Singapore)

 

[zlatkodo]

You can make winding with 6 leads out and you'll have both: 230V, Delta and 400 V,Wye.

 

[Parchie]

@zlatkodo (Electrical),
That was what I was saying in my last post. I'd bet my money that his motor is 230/460V (6 leads out). He just has to reconnect the leads to match with his VFDs output!

 

[zlatkodo]

Hi,Parchie,
Just small correction.
- You can't create motor 230/460V with 6 leads out. You need 9 or 12 leads.
- For 6 leads out the voltage ratio should be √3 = 1,73 (not 2).
Regards
ACW

 

[che12345]

@ Mr. Parchie (Electrical)17 Jul 22 14:56
"....That was what I was saying in my last post. I'd bet my money that his motor is 230/460V (6 leads out). He just has to reconnect the leads to match with his VFDs output! "
Thank you for your valuable advice.
1. The location is in Asia, where IEC prevails. Per IEC, the standard LV voltage is 230/400V 50Hz i.e. 230V 1-phase and 400V + N 3-phase. IEC motors are with 6 terminals brought out supplied with 3 external links. The windings are rated 400V. it would be suitable for SD starting or DOL starting at 690V when linked in Y formation.
The motor at site is an IEC design with 400V 50Hz windings. It is linked in D-formation suitable for 400V mains.
2. As rightly pointed out by Mr. zlatkodo, "....For 6 leads out the voltage ratio should be √3 = 1,73 (not 2)...". The motor at site is with 400V winding. It is linked in D-formation. It would be also suitable for 690V if linked in Y-formation. Note: 690V 3-phase is NOT available from the public utility.
Che Kuan Yau (Singapore)

 

[edison123]

A 230/460 V is 1:2 input voltage winding which has two sections, which are connected in series for 460 V and in parallel for 230 V and requires minimum 9 terminals, which normally does not happen in IEC world.

A standard 400 V, 50 Hz IEC world motor with 6 terminals is designed to start in star and run in delta via a star-delta starter or directly start and run in delta, if the supply system permits it. If that motor is fed 230 V directly in delta, the output will get reduced to 58% and the torque to 33%.

OP's motor can be VFD duty rewound in star (instead of OEM's delta) and with 6 leads out, the motor can run at both 230 V in delta and at 400 V in star with 1:1.73 voltage ratio. All he has to do is connect the links at the motor terminals in delta for 230 V and in star for 400 V. This is the simplest, quickest and cheapest solution.

And no, a 230 V VFD is not going to output 400 V on its own.

Also, any theorizing about 690 V is quite meaningless in this thread.



Muthu

http://www.edison.co.in

 

[LionelHutz]

Yes, it is getting tedious.

A transformer either before or after the VFD.

There are plenty of VFD's suitable for use on 400V single phase input, just have to ask the manufacturers instead of looking at the tables in data sheets or manuals.

The transformer for between a VFD and motor just isn't that big a deal. General purpose 3-phase motors will run on a VFD at full power, so why would a transformer require much special? If the standard transformer sizes are 9kVA or 15kVA in your part of the world then go 15kVA and get at it. This is a pump, so higher speeds only. Another application with lower speed requirements would need a transformer that can withstand higher V/Hz to make low speed torque.

 

[EngRepair]

Perhaps something like that:
[URL unfurl="true"]https://www.youtube.com/watch?v=oDI1YxDDEB8[/url]