Re: Spindle and VFD pairing
Hello.
I think you should have no problem as the VFD is of higher capacity than the motor. Yet some cautions. Remember to set the drive for a lower current limit and the fuses and/or thermal breakers selected accordingly.
Regards.
Re: Spindle and VFD pairing
Great news, thank you. I am sure I will be back with more questions once I need to set it up.
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
Great news, thank you. I am sure I will be back with more questions once I need to set it up.
why would you even consider such a large VFD Drive 3Kw with such a small 800w spindle the the max you should look at is 1.5Kw for that size spindle
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
Because it is lower cost and has a faster delivery than the 1.5kW version. Is there a reason not to use a larger VFD? Is it less efficient, or not compatible for some reason?
Less efficient for sure, compatibility not even close
Miss one Parameter setting and the poor little 800w spindle will be smoking before you can turn the VFD Drive off, it is not easy to dumb down a 3Kw VFD Drive to be used for a 800w spindle so if you are new to this then don't buy the 3Kw VFD Drive, besides this you most likely don't have the supply power needed to run it on single phase
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
Is the VFD really going to use more power when the spindle is only 800W?
The VFD Drive has to reach it's Bus voltage of 338v to 370v and it does not care how it gets there you have higher capacity components so yes it will use more power, if it can't reach the Bus voltage it will fault
240 x 1.41= Bus voltage this will very slightly depending on the input supply voltage
But I just remembered you are using 120v supply that makes it even worse, this is the most bazar thing I have ever heard on here 3Kw VFD Drive on a 120v Single Phase supply Good luck with that
Re: Spindle and VFD pairing
Hello.
When using a VFD larger than the driven motor the VFD will supply whatever power the motor requires. The way to know that power is mainly throught the current demanded. It is true that the VFD will take for itself some additional power than what an appropiately sized VFD would take but normally not to much.
The problem that might arise is that if the motor gets stalled and the current limit is not set correctly the drive will be able to supply that extra current and thus burn the motor and in doing so probably damage itself.
Using larger VFDs than the driven motors while possible needs to be carefully applied.
As a comparison given the appropriate distances is your own house electric wiring. You can install a 30W lamp and the electric system will deliver the required current for that lamp. If you later change it for a 100W lamp the current now required will now be delivered.
Now just imagine that you add a lot of 100W lamps. Your electric system will still try to deliver but if not correctly sized fuses are used the whole electric installation will burn probably causing a fire.
In our shop we used to have one or two oversized drives just in case one in the factories we served failed.
In many cases we ended up adapting a "chipote" (mexican word for a protruding bump in the head). That helped us keep the machine downtime to a minimum while we were able to repair the failed drive.
There are too many motor sizes when you make from pins to airplanes.
As I stated before you need to carefully select the fuses and thermal breakers not to mention the settings of the drive.
Regards.
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Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
But that would be the same with a 1.5kW 110V VFD?
No not at all the current draw will be less for the 1.5Kw
This will give you an idea of what to expect when using 120v supply and the current required this is for 220v / 240v supply you have to double this for 120v supply
If you need more examples I have lots of them, every manufacture posts this information
Re: Spindle and VFD pairing
A VFD when powered Charges a large 3phase rectifier fed Capacitor reservoir bank, this DC reservoir bank will be (or should be) kept charged to keep up with the anticipated demand of the 3ph switching circuit.if the drain on the bank is low, then the re-charge (supply) current demand is also low.
e.g. When the motor output is zero, then the current demand on the bank is comparatively zero also.
Al.
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
I understand the maximum current draw can be higher for the 3kW than the 1.5kW, but when using each to drive the 800W spindle, they’ll current draw should be about the same, correct?
Yes it would be about the same, the problem I see is with the 120v supply, I think if you get this VFD Drive it will be a 220v drive and not a 120v in the spec's it says it has a 3Ph bridge rectifier there is no such thing in NA as a 3Ph 120v
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
The spec says 110V single phase for the input, so I should be okay.
It does also say 50Hz, and I am in the USA and use 60Hz, but the supplier said it was compatible.
That is what is advertised, is it on the Nameplate of the VFD Drive
50Hz or 60Hz is just the default of the VFD Drive it has nothing to do with your power supply frequency
Re: Spindle and VFD pairing
Quote:
Originally Posted by
garrett1812
The spec says 110V single phase for the input, so I should be okay.
It does also say 50Hz, and I am in the USA and use 60Hz, but the supplier said it was compatible.
If you check a 220v 3Kw VFD you will see it has the same 13A rating for your 110v to be 3Kw it would have to be 26A so what you will be getting is a 220v VFD Drive which may be labeled 110v
