What to look for in a VFD?

I purchased a WJ200 series VFD from driveswharehouse on ebay. They had the best price I could find anywhere at the time, the unit shipped fast from the US, was new and exactly as described and their seller rating is perfect. I don't believe that at a price difference of 100 USD that you will be getting the same quality VFD.
 
Thank you, it is now about as clear as mud. :) I have just accepted that unless you are really into these things you can't rely on reading spec sheets to get the full picture.

I talked to a tech at Wolf automation and went with his recommendation for a "budget" VFD, a Fuji Electric and chose a 2hp model just in case I ever go bigger. The 2hp was only $30 more than the 1hp. $200 shipped so a little more than twice the price of the cheapest ebay VFDs but I appreciated being able to actually talk to someone in tech support who would listen to my use and explain why he was recommending a particular unit. It gives me some reassurance in case I need future help or need to use the 3 year warranty.
 
A bigger VFD than what you actually need for the project at hand is not a liability in any way. It costs more, but gives you more flexibility down the line, and can help if or when you sell it some day.

Wait, a bigger VFD will likely need heavier wiring going to it, and higher rated circuit breakers, so that it is safe, regardless of what size motor you are running off of it up to it's maximum rating. That can cost you more money yet.
 
Good point about the wiring, but in this case it shouldn't make any difference since both are under 15A.
 
Actually Bob's point is valid. The wiring for a VFD is not based on the output wiring/motor current but the input rating of the VFD. It could pull full current of the rated VFD independent of the motor load. A 2 Hp VFD typically specifies a 30-40A fuse rating depending on the type of fuse, a breaker rating of 30A at 230 VAC for 2-3Hp. The Fuji Mini specifies a 30A J class fuse or 20A breaker at 230VAC for the 2 Hp VFD. You can get by with a 20A breaker circuit. The breaker is suppose to be rated at 125% of the input amperage of the VFD, there are also some rounding rules for breakers. If you are adding 230VAC circuits, consider a 20 or 30A breaker. The wire from the breaker to the VFD would need to be sized according to the breaker size. Breakers typically protect the wiring and prevent fires from short circuits/overloads, fuses are meant to protect equipment, but at this level of VFD they are a toss if they fail.

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Actually Bob's point is valid. The wiring for a VFD is not based on the output wiring/motor current but the input rating of the VFD. It could pull full current of the rated VFD independent of the motor load. A 2 Hp VFD typically specifies a 30-40A fuse rating depending on the type of fuse, a breaker rating of 30A at 230 VAC for 2-3Hp. The Fuji Mini specifies a 30A J class fuse or 20A breaker at 230VAC for the 2 Hp VFD. You can get by with a 20A breaker circuit. The breaker is suppose to be rated at 125% of the input amperage of the VFD, there are also some rounding rules for breakers. If you are adding 230VAC circuits, consider a 20 or 30A breaker. The wire from the breaker to the VFD would need to be sized according to the breaker size. Breakers typically protect the wiring and prevent fires from short circuits/overloads, fuses are meant to protect equipment, but at this level of VFD they are a toss if they fail.

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I looked on the spec sheet where it says 5.5A for the 1hp or 10.5A on the 2HP. I guess that must relate to the load the VFD can handle rather than what the VFD requires. It hasn't arrived yet, so I haven't dug into the paperwork.

I'll do some 115v electrical work myself, but I get an electrician whenever I need any 230v stuff done so when the outlet gets done it will be sized appropriately by a professional. I like my house and really dislike electrical fires.
 
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