new vfd

[kevin largeParticipant @kevinlarge76611]

I need to get a new vfd for my boxford it has a .75kw motor can I use a 1.5kw rated vfd ?

[kevin largeParticipant @kevinlarge76611]

[David JuppParticipant @davidjupp51506]

Generally you can use a higher powered VFD than your motor needs, there are setting for the motor rating in the VFD parameters, make sure to set these correctly if you want proper protection for the motor.

[John RuddParticipant @johnrudd16576]

No problem at all….

If the inverter has a programmable parameter for motor max current, you should input that into the relevant parameter to provide protection against overload..

You may need to input the number of poles/speed of the motor too..

Which inverter have you got in mind?

[not done it yetParticipant @notdoneityet]

If it is a very cheap chinese VFD, it may well not protect your motor from overload. There are now plenty of smaller sized items available at similar, or lower prices.

Better to use a larger size of VFD as it may not have the capacity for a motor rated at 0.75kW output but low efficiency. Typically this might include motors rated for a low run-cycle ratings.

As one should not leave a machine running, without being in attendance, a stall or heavy load situation could be avoided by the operator. This would not be the case for unattended drives.

The motor could be protected on the single phase side with a current overload trip. Many VFDs don’t like switching on the motor side, but disconnection on the mains feed to thievVFD must be tolerated, for possible mains failure events.

[kevin largeParticipant @kevinlarge76611]

Posted by John Rudd on 22/10/2018 19:16:43:

No problem at all….

If the inverter has a programmable parameter for motor max current, you should input that into the relevant parameter to provide protection against overload..

You may need to input the number of poles/speed of the motor too..

Which inverter have you got in mind?

eBay item number:

323255847117 this is the one I am considering thanks for your input

[KWILParticipant @kwil]

Seller is in China, much easier to deal with a UK based seller should any problem arise.

[John RuddParticipant @johnrudd16576]

Cant say I'd endorse that particular one, there's no manufacturer branding……

I've used IMO/Teco vfd's of varying hp rating without any issue…

 

Edited By John Rudd on 23/10/2018 19:34:41

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