[mhessler]

Hi folks!

I'm kicking off the conversion of a Charter Oak 12Z ("IH" supersized RF45) and going through each major piece in separate threads and forum areas to hopefully make the various "chunks" easier to find. I'll add quick summaries and thread links to the "main" mill conversion thread once that gets going.

One of the first things I'm going to want to do to this machine is remove its 2HP 1ph motor and put a proper VFD on it. I've got 220V/1ph available, and for what I'm planning on using the machine for a 3HP spindle drive should be more than enough; luckily that's about where the 1ph-input VFDs top out at. I plan on running an inverter-duty 2 or 4 pole motor, ideally in vector control for best low-rpm torque.

3 VFDs that seem really popular for these operating conditions are:

1) Hitachi WJ200-022SF
2) Teco N3-203-CS
3) DuraPulse GS3-23P0

These are all relatively available and are all about $350. I get the impression that the Hitachi and Teco units have been around for donkeys' years so I'm not sure if people are selling new-old-stock or if they're actually current modern production; the Tecos seems a bit more scarce, e.g. some sites have them in their catalog but not "in stock". The DuraPulse is a current product.

I've read lots of positive reviews of peoples' WJ200s, and people talk about them being loud (perhaps they tend to PWM at lower freqs?). That may be just a nuisance; it seems the biggest gripe is that the manual is both impenetrable and also just flat out incorrect on some important items. That's mitigated a bit by awesome sites like this but still aggravating. I read the 2011 thread in this section regarding settings on one of these things.

I haven't seen much about the Teco N3s, other than they're a competitive unit to the WJ200s and, unlike the Teco JNEVs, will actually do a decent sensorless vector mode with sensible self-tuning. Basically the threads I've seen were questions/complaints about Teco JNEVs, with people saying "get a WJ200 instead" or "oh Teco's newer N3 doesn't have that problem".

The DuraPulse is interesting simply because I believe it's the most modern of the bunch, and it also has the option to add a $60 encoder input card for really really tight closed-loop speed control. That said, I'm not sure I care on a CNC mill application; if I want that last few percent accuracy on spindle control, I'd probably just run an encoder on the spindle itself and run it back to the motion controller to enable things like rigid tapping. Right?

What say ye, thousands of years of collective experience? Surely many folks here have run one or more of these exact units (or the model line siblings) and can report on their reliability, ease of use, relative build quality, features they love or hate, etc...

Thanks everyone!

Cheers,
-Mark

[SWATH]

I used the durapulse gs3-23po with the encoder feedback card and braking resistor. Thoroughly impressed. Automation direct even replaced everything after a few months of use when an errant arc from the resistor leads caused some damage to the braking resistor module. I called about it in a Friday night and had all new stuff on Monday. It could have been avoided with longer wires on the resistor. Other than that no problems.

[mactec54]

mhessler

1) Hitachi WJ200-022SF
2) Teco N3-203-CS
3) DuraPulse GS3-23P0

Hitachi already have an Encoder feed back built in, the Teco also has pulse detection (PID) control built in, this is of no use, unless you are doing auto tool changes, or need help with your spindle encoder for Ridge Tapping

There would be no use what's so ever for a normal machine,that doesn't have/use these features, for a machining center that needs to control the spindle speed & motor speed,It has feedback to the control,from the spindle Encoder & the VFD Drive, this is were this is used, the control also has to be able to accept, the Spindle Encoder feedback & the feedback from the VFD as well for this to work

If your control can't do this then there is no point in having an encoder for feedback

[awerby]

I've used Hitachi and Teco VFDs, but never tried the DuraPulse. The Hitachis have always worked fine, and were relatively easy to set up. The Teco was more difficult to set up; the manual was virtually incomprehensible. It burned up shortly after installation, and Teco refused to honor their warranty, saying it "must have been struck by lightning", which I guess would be an Act of God.

The encoder feedback would be useful if you wanted to do rigid tapping, but as Mactec points out, if your controller doesn't support that, there's no point in paying extra for it. Make sure you get an inverter that's about 33% oversized for your HP rating if you need it to convert single to triple phase.