[Glacern]

Hey fellas,

I'm about to jump on board with the rest of the Sharp mini-VMC owners out there. What size of a rotary phase converter would you recommend? Will a 20hp be sufficient? Voltage stabilizer required? I don't plan on pushing the machine very hard.

I've currently got a 10hp Phase-A-Matic that works well and will likely get another from them.

How much starting current does a 20hp RPC require? My power source is a 100A single phase line that is shared with the rest of my house.

[PBMW]

I'm not a fan of using a rotery phase comverter on a CNC. I have three phase perfects in my shop. the one on my Sharp is a 10 hp.

[timlkallam]

I have a sharp mini mill I use a 30 hp rpc because i have a 15 hp cnc lathe, but as a general rule the RPC should be twice the hp as the cnc spindle motor. In you case you would need a 15 hp rpc .I have a shop in my basement
I run the sharp mill and the cnc lathe 28 8 foot light fixtures 30 hp rpc ,air conditioner on 100 amp service and never had a problem.
But if i were you and were starting a new shop i would by a phase perfect just so i would not have to listen to the rpc.

[Glacern]

Thanks for the rec on the Phase Perfect.

[krfrea]

I moved my rpc to a dog house behind my shop...best thing I did in a long time

[Turul]

I agree with PBMW and would not even think about rpc for a computer controlled machine again, after my little exercise I had to go through. Started with a 30HP rpc but it drove 30+ Amp through the controller when the VMC was not cutting - 40A fuse soldering melted, the Fanuc controller was heating up.
I panicked and sent back the rcp and got a 10HP phase perfect. That was the end of my trouble. Don’t forget a 20-30HP rcp continuously burns extra 8-10 Amps at 220 Volt the kWh are adding up quickly.
Cheers

[kochevnik]

I bought a new Sharp 2412 in December - and I bought a RPC off of EBay - just some generic thing - had to send unload it on Craigslist because the instructions sucked so bad I couldn't figure out how to hook it up.

Next, bought an 10 HP American Rotary off of EBay - better, but I had to drill into the enclosure because they didn't have any knockout on it. Works good, but it is noisy. I also run 2 hydrovane compressors and the spindle on the mill itself makes a lot of high pitched whining noise at 6000 RPM + So now I just wear ear protection all the time.

Don't know about voltage stablilizer but I did need to buy a buck boost transformer to knock the voltage down from the 247 volts the power company sends to my house. Make sure you check that - the Fanuc needs under 240 volts max. I haven't had any problems, but then again I haven't had the mill long either. Keep in mind the Fanuc controls run off of 24 volts DC - there is a transformer in the back cabinet. Those internal power supplies do a good job of keeping the power steady - I wouldn't worry a lot unless you have trouble with a lot of other electrical equipment at your place.

That being said, if you got lots of money, I would get a phase perfect. That's on my list of upgrades to come, not just for the stability but mainly for the noise. Someday I hope to only hear my mill in the shop

One last note - I would be remiss in not mentioning this because it pissed me off when I got my Sharp : the rapids on the sharp are NOT 1181 IPM, they are 787 IPM. Of course the literature and the website says otherwise - take it for what it is worth.

I like the Sharp, but if I had it to do all over again, I would pay an extra $3500 and get a Bridgeport XV-710 - 50 percent faster rapids, 50 percent bigger table, 50 percent heavier and twice as many tools in the toolchanger. Linear instead of the box ways though.

Just my 2 cents.

[PBMW]

Interesting about the Bridgport.
When I bought my Sharp, the advertised rapids were the 710 that is does. I'm happy with mine. I would have thought twice about it if I knew the dif wa only $3500. But as it works out, I really needed a box way machine. I have two linear guide mills, one is a Haas Mini an dthe other is an Akira Seiki 4020. All of them have their place in the shop.

[fpworks]

I have a different opinion on RPC...sure a digital phase converter is better, but a RPC will work as long as you don't cut any corners on ANYTHING. The biggest problem I had with the RPC is that I needed a 100 amp slot on the panel to guarantee that the VMC had 30 amps of available triple phase power. With the Phase Perfect, you won't have that problem.


I suppose I got lucky with my experience with a RPC, but I have a bit of trouble believing that since I hear many stories about misapplications of RPCs. I used a 20hp RPC for my Fadal when I started our business in my house. I bought the RPC new, sized everything correctly, and hooked it up to a brand new machine. I put about 2000 hrs on the machine and nothing missed a beat. Since then, that machine resides in our shop and I left the RPC behind. The machine runs in the shop just like it did at my house.


Turul, there was something wrong with your RPC unit or connection to your machine...it sure as hell shouldn't be pulling that type of power when idle. Likewise, the RPC doesn't drive power through any source, in your case your machine control. The source pulls power from the RPC, which is really just a transformer. When you are not pulling any current throught the RPC, the only energy consumed is the power required to sustain the idler, which is under nearly zero load.

[vpcnc]

Just my 2 Cents...
Check with Fanuc before you hook up a RPC...
If it's a Brand New Machine, chances are Fanuc will not cover any warranty issues when using a RPC...
I've run into a few issues regarding warranty problems and RPC...
Digital Phase converters are OK...