# Single Phase Supply Vfd

3 replies to this topic

### #1 billstrong

billstrong

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Posted 22 December 2008 - 03:22 AM

Hi all,
I am a fresh man,I have got the following questions:
1.input for vfd is 230v two phase, bus voltage is about 400v, drive a delta connected three phase induction motor
2.input for vfd is 380v,three phase, bus voltage is about 600v, drive a star connected three phase induction motor
3.modulation scheme is SV-PWM for the above two cases
is the max speed for the motor the same in the above two cases?
Thx!

### #2 billstrong

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Posted 22 December 2008 - 04:32 PM

QUOTE (billstrong @ Dec 22 2008, 11:22 AM) <{POST_SNAPBACK}>
Hi all,
I am a fresh man,I have got the following questions:
1.input for vfd is 230v two phase, bus voltage is about 400v, drive a delta connected three phase induction motor
2.input for vfd is 380v,three phase, bus voltage is about 600v, drive a star connected three phase induction motor
3.modulation scheme is SV-PWM for the above two cases
is the max speed for the motor the same in the above two cases?
Thx!

or to simplify the question:
1.if the bus voltage is 400v and ACIM is delta connected
2.bus voltage is 600v and ACIM is star connected
is these two case equivallent for the ACIM?

### #3 marke

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Posted 24 December 2008 - 08:31 PM

Hello Billstrong

A single phase input VFD connected to 230 V single phase input will put out 230 volt three phase.

A three phase input VFD connected to 400V will put out 400V.

Some small three phase motors are designed to be delta connected for 230 volt and star connected for 400 volt.
Provided that you configure the motor correctly for the voltage applied, the performance will be the same.

Note: Many motors are designed to be delta connected for 400V operation. You can not use these on 230V.

Best regards,
Mark.

### #4 billstrong

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Posted 25 December 2008 - 07:43 AM

QUOTE (marke @ Dec 25 2008, 04:31 AM) <{POST_SNAPBACK}>
Hello Billstrong

A single phase input VFD connected to 230 V single phase input will put out 230 volt three phase.

A three phase input VFD connected to 400V will put out 400V.

Some small three phase motors are designed to be delta connected for 230 volt and star connected for 400 volt.
Provided that you configure the motor correctly for the voltage applied, the performance will be the same.

Note: Many motors are designed to be delta connected for 400V operation. You can not use these on 230V.

Best regards,
Mark.

Hello Mark,
Thanks for you help!
Have a nice christmas!

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