Phase Converter Sizing & Compressor

[TravisR100]

I'm looking at the Kaeser 5C.
http://buykaeser.com/store/product_i...products_id=30

I believe this one cycles the motor on and off as well from what I can tell. Any good suggestions on the scroll compressors?

[123CNC]

Atlas Copco is one. But seeing that you are looking at a 5 hp, the aforementioned staged units don't really come in to play until you start looking at multiples greater than five (typically multiple 5 hp units).

Atlas also offers dryer and scroll compressor packages, unsure if any of them include a receiver tank.

As an all in one, the Kaeser your looking at looks like a fair deal. A similarly equipped scroll package with tank might end up being a little bit more money, but I don't know for sure.

[rawen2]

I was wondering if anyone here uses a rotary vane compressor?
In a plant where I used to work we had a 75HP Hydrovane that ran 24/7 except when we stopped it to do preventive maintenance. I was impressed with its reliability.
Here's an example I found on eBay:
http://cgi.ebay.com/CompAir-Hydrovan...d=p3286.c0.m14
Ralph

[TravisR100]

123cnc, thanks. Yep, the Kaeser just looked like an awfully nice all-in-one unit. Compact, components designed to work together, apparently a good brand. Luckily they have a storefront here in Houston so I'm going to stop by next week to take a look at one.

[mls]

I have vf-3 2006 20hp and a 2002 mini mill standard 7.5hp I only have 100 amp running to my garage and only 200 amp in house I have never had any problems yet.
I run the phase perfect I put a 100amp breaker to it I run the vf-3 and my bridgeport off of this and the mini mill of single phase these both run at the same time all day long with the saw, bridgeport , and my ingersal rand 60 gallon 3hp compressor no problems yet 1.5 years.

I cheaked the power draw at the machine when I installed it (vf-3) and when it starts the spindle from 0-7500rpm it only pulled I think it was like 17 amps the 50 amps would be every motor at peak power.

I have since built a cnc plasma cutter with a 60 amp hypertherm torch unit and use this while running everything else except the mini mill with no problems.
I hope this help I would get the second size converter ($4000 one) and get a 5hp compresser (unless you will be blasting all day long).
Good luck Mike

[TravisR100]

mls, which phaseperfect model are you using?

After talking with my electrician I too am thinking I might not have to bring in another 200 amps of service. The question is what the peak draw is on my house at the moment. I just ordered one of these nifty devices to hopefully answer that question:

http://www.theenergydetective.com/what/overview.html

and here's a review of the unit:
http://inspiredaustin.com/blog/2009/...rgy-detective/

[Geof]

Originally Posted by mls .....I cheaked the power draw at the machine when I installed it (vf-3) and when it starts the spindle from 0-7500rpm it only pulled I think it was like 17 amps the 50 amps would be every motor at peak power...

How did you check this, analog clamp-on ammeter on the incoming three phase lines or digital? The peak current draw is only for a very short time and it is difficult to get a good reading; digital meters can be very bad depending on their sampling frequency and analog meters which are highly damped are also bad because they do not respond fast enough.

I checked the peak current into a VF2 just for spindle starting and it was 50amps but this check was done using a scope.

[TravisR100]

msl, so do you have a total of 300 amps of service? Or is the 100 amp in your garage simply a breaker off the house 200 amp service?

[lkenney]

We run rotary Phase Convertors one for each of the mills and lathe. I fried the Fanuc control on the lathe trying to run both off the same 30hp convertor. Sometimes you can send wild phases back through your system by reversing a spindle and that is what kill the Fanuc according to the repairman that came with a load of parts to switch in and out until he got us working. Cha-Cheng. Each convtor is on an 80 breaker and of course they are never all started at the same time. I switch each on on after the previous one has reached full speed.

I also got in trouble with my PUD for running too big of a motor on a residental service even though I had contracted for a 320 amp service for the house so I could wire the shop when we built it. We had to bring in a commercial 320 amps for the shop plus buy a new transfomer for the feed. Make sure you have read the fine print from your power supplier.

Lowell