Ok thanks for that info.
Would a 3hp 2.2kW VFD run a 3hp motor?
If the output of a VFD is 11A @ 220v the output is 2420W (Or rounded to 2.2kW) A leeson model is available to convert from 1ph to 3ph with an output of 2.2kW.
However is a 5hp 4.0kW a better choice?
A local motor house supplied a Leeson drive for one of their customers that was rated for single phase input at the rated h.p. output. I specifically asked why it wasn't rated double like the others and that was the answer that I got. You need to check the ratings for yourself.
I have a customer with a VFD that has been converting single phase to three phase for years. It was rated at double the motor rating because the input rectifiers have to handle the input current at 1.7 times the motor load. In fact, I've installed at least a half dozen sized that way - sized by Leeson.
If it's going to be a hard start, get a vector drive. Apparently, they have better torque.
I have two drives that I am responsible for that are hard starting.
One unloads grain from a silo and, when the material freezes, it has to be broken free. I installed a switch to reverse the motor so they could plug it back and forth. The drive will look after the motor and itself.
The other pressures hydraulic lines to test oil wells. When it has to start from a stall to bump the pressure up, it can shut down on an overload fault and has to be manually reset after a few minutes.
There are settings on the drive to allow a higher overload for starting torque. I can't say how a drive compares to a motor across the line because I haven't had an opportunity to make the comparison. If you use a drive, your results aren't guaranteed.
I was put off drives when Leeson refused to warranty a drive because the input rectifiers where blown. I don't give a rat's ass about their excuses, so I supplied the replacement drive and installed it at my own cost. My warranty is good even if Leeson sucks. Still, Leeson drives, at least here, are about 25% cheaper. My deal with the motor house, now, is that they sell the drive direct and supply the warranty.
I did have another manufacturer warranty a couple 50 h.p. drives that were manufactured with the wrong rectifiers, but even then they didn't cover labour or temporary replacement parts.
Make sure you have enough profit that it is worth the risk. If it doesn't work, you are going to own a drive.