Vfd For A Bridgeport

Hitachi makes good drives. The one you linked to is a 1 HP rated drive. I would assume your BP mill has a 1-1/2 to 3 HP motor, so that unit would not be adequate. It is a general good practice when converting single phase to three phase to go to an overrated VFD, like perhaps a 2 HP rated drive or higher to run a 1-1/2 HP motor. At least that is my understanding, others here know lots more than I do about VFD's.
 
I have one of those sitting out in my shop that went up in smoke after about a year. But I suspect that is not normal. Most VFDs are pretty bullet proof.

As Bob says, over rating VFDs for the motor when operating on single phase is not a bad thing. I use Automation Direct VFDs and have had good luck with them, and use one's rated at the motor HP.
 
As Bob mentioned, I would size the VFD to the machine motor Hp/ratings. Not really any need to go up a size in the VFD, unless you are planning to put in a bigger motor at some later time. Most VFDs are rated to deliver 130-150% of the motor rated current for short periods. The Hitachi NES1 would work fine for a mill application (would not use this for a lathe), it is more of a bare bones VFD and is lacking a few features like it does not have provisions for an external braking resistor and it will not run sensorless vector. The latter which is lacking in most lower cost VFDs, it gives better motor control at lower speeds (below 30Hz). Hitachi seems to make solid reliable drives at reasonable cost, other then Jim's experience I have not seen/heard one fail in the field. Teco also has a new low cost line of of VFDs, but a few people have had some issues with them. The Automation Direct GS2 and GS3 are also decent. I would buy from a mainstream US supplier, so if there are any problems or need technical help there is a resource.

One thing about the Hitachi and a few other drives, is that you need to unlock the unit in able to do any programing changes, so on the Hitachi VFDs you must do the following first:
1. Change B037 to "00" for full display of all functions. You must press both the up and down arrows to access single-digit edit mode since this feature is not accessible in the default basic display. You must change B037 before you can change B031.

AND THEN
2. Change B031 to "10". This unlocks all the high level program functions for editing. Then make the following program changes that are highlighted.
 
It is also often pretty cheap to go to a larger capacity VFD at the lower power ratings. The 3 hp rated VFD I just bought was $4.00 more expensive than a 2 hp rated drive from the same supplier. The larger one will only consume slightly more power at lower outputs than a barely adequate one will, will be usable on larger machines down the road, and will be easier to sell, and for more money, later on. When you get into bigger VFDs, like 5 hp and larger, they get more expensive very quickly as the power rating increases.
 
In general I agree that go one size bigger on the VFD, if the price difference is not significant. Given that the NES1 is a budget VFD, I assume price was an issue. I often see a significant price jump from 1 to 2 Hp units, in this case it is another $40+ to size up. On the other hand I did a 3Hp motor with 3 phase power installation with a WJ200 and opted for the 5Hp VFD because the price difference was nominal. I also considered that the machine might be replaced with a larger 5Hp unit at a later time. You will not get any performance difference between the two, and it is unlikely to see any difference in parts longevity, as the VFD will be obsolete by the time it fails. If I where in a very hot environment, continuous duty at close to full load, then I think one could make an argument to size up based on the VFD components not being stressed to their maximum ratings, and the capacitors in theory should last longer. That being said, on my new 3Hp (Acra/Sharp) mill, the manufacturer undersized the VFD. The manufacture says they have no issues, Yaskawa tech said it is not rated for a full 3Hp in the wired configuration. Given that the load is usually way under the full potential of the Hp, and it is not being run at full Hp continuously, I guess they can get buy with a smaller VFD.

I usually do VFD builds where the VFD is integral with the machine control system, so unlikely to be re-purposed at a future point. They are not very expensive in the 5Hp and under size, and the technology is evolving, so kind of a moving target on whether to reuse an older VFD or just buy a new one. Also, per the manufacturer's guidance, if you up-size the VFD, the input wiring, fusing, switch gear must be rated for the VFD rating and not the motor rating.
 
I appreciate the responses. Not sure on the HP of the motor but will know tomorrow when I pick it up. I'm willing to spend the extra money for external braking resistor and sensor-less vector capability. Also want external switch for start/stop & direction. I don't see up sizing the motor as I doubt I'll push this mill very hard. It's strictly for hobby use and some personal gun work. The first projects are fixtures and mods for my Atlas lathe. Once again, thanks for the input and I'll be checking these other suggestions out.
 
Lenze is a well regarded German manufacturer, AC Tech has been building drives in the U.S.A for a long time also. I'm guessing that Lenze bought AC Tech. That looks like it will do a fine job.
 
I think Lenze is what we have on the hangar door drives at work, seem like real nice units. Got my mill home today, motor is 1 HP pancake type. Seller said he had it rewound when he got it, the Glyptal on the stator still looks new. I don't see putting anything larger on. The pricing on the Lenze is not objectionable, and I like German quality. Probably go with one of these. Once again thanks for all of the helpful input.


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