Rotary Phase Converter Experiences?

jazznpool

jazznpool

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I am looking into purchasing a 5 hp USA made rotary phase converter for my garage workshop to power a 220/ 3 phase machine with 4 prong plug. I've seen a range of prices between 600.00 and 1,200.00. The rotary converters I've looked at online weigh from 93 to 203 pounds. I'd like to get it right the first time. Any suggestions? Thanks, Martin
 
I'll share what little I know from my experience with rotary phase converters.
Rotary comes the closest to matching the efficiency of true 3-phase, somewhere in the 90%+ range.
Static phase converters, those with no moving parts, I'm told are less efficient, 80 - 85%.
There are some manufacturers of 3-ph machinery that will void their warranty
if their machines are run using static converters.
Basically a 3-ph rotary is a large(r) 3-ph mtr that uses a capacitor-bank to generate the 3rd leg.
The sizing of the cap-bank is key to the unit's efficiency.

Sizing of the converter itself is based on the total demand of the unit.
Ex: I have 3 machines that require 3-ph current. Their total combined demand is 5-hp.
My converter is 50% larger than the demand or 7.5hp.
If I could physically start all 3 machines at the same time, none would lose power.

There are certain advantages to 3-ph which I appreciate, dynamic braking and instant reverse.
With lathe-spindle running fwd, I can 'bump' reverse and stop the spindle like right now (dynamic-braking).
I tap under power, not by hand. The tail-stock is much truer at keeping the tap straight.
Once the tap nears the bottom of the hole I just hit reverse and walk the tap out of the hole.

I will admit that I'm not a licensed electrician though I did work Ind. Maint. for 10 yrs.
I know probably just enough to keep everything in my shop running.
My converter was built for me 25 yrs ago and has been performing flawlessly ever since.
I consider it a good investment.

HTHs, KJ

The wght. of the converter is almost irrelavent. Once set in place you'll never touch it again.
 
I bought one from American Rotary five years ago. Paid about $600 and couldn't be happier with it.

Larry
 
Martin

You may want to consider buying a Variable Frequency Drive if all you're needing to power is 1 machine.

A VFD will take in 220/230 single phase and output 3 phase. They can be purchased in many different size of capacity ratings, and you get the advantages of being able to adjust the speed. The VFD's, because they basically create the 3 individual phases, and alter their frequency to change the speed of the motor. Most newer designs come with Sensorless Vector Torque control. Basically, it senses the load and will work harder to keep the motor from slowing down under load.

Here's a very good quality model from Hitachi:

http://www.ebay.com/itm/HITACHI-WJ2...185?pt=LH_DefaultDomain_0&hash=item1c53e76a11

You can also instant reverse with it, as well as it makes it easy to wire up because you can use a remote switch so you don't have to run the 3 phase power cables to and from your switch.

Just something to think about.


Royce Bunnell
www.obcues.com
 
Static phase converter

Martin

I'm running a static phase converter on a 2 hp metal lathe. I don't have any other 3 phase machines or I would have opted for the other options mentioned above. It has work well for the last 10 years. Mind you, according to the manufacture there is a drop of 25% but for what we use the lathes for is insignicant. At least I've never had the need for more power at low speed or even at full speed. That's my experience on a lathe, don't know about any other machinery.

Martin
 
I've been running a static converter for over 20 years with no problems except I blew a condenser once by shorting it to ground. I've also got a Enco 13X36" lathe and a Jet 12X40" lathe utilizing a VFD. I couldn't be happier with the VFDs.
I put one on the Enco and as soon as I bought the jet I ordered the needed parts as I knew I would never use the lathe without having the access to variable speed. I upped the rpm from 1800 to 3600 and then geared it down so that I wouldn't take a chance of blowing a chuck. I can now run about 3 rpm to about 2200. The slow speed is great for threading.

I installed a 2 HP 3 phz motor as the VFD controller never automatically converted from single phase to 3 phase. The Enco does convert.

Although prices have probably gone up, I bought new off of ebay and got both the motor and the converter for around 200.00.

Probably the second best buy since acquiring tools for the last 25 yrs.

Dick
 
It all depends on the machine.
For 220 v 3 phase I use a VFD for the size rating motor.
I worked in a shop with 440v cnc machines. They had the electronic converter and 2 rotary converters. With the manual mill and manual lathe, only needed the electronic on. But with the cnc, always used the rotary. If there were a lot of machines running, ie more than 4, then both were turned on. I am not an electrician, so don't know how it all tied in, but it worked.
Neil
 
I have been running an American Rotary Phase converter for years and am pleased.

They are very helpful in helping you pick the right size for your machine.
 
We sure like to know why you need 5HP of power .
Are your drilling for oil ?
:grin:
 
Who? Me? OK.

My BridgePort type mill is 2hp, 2-spd mtr. Will spin 5440 rpm.
My Sheldon 13x28 lathe is 1.5hp. It's maxed @ 1200 but that's quite enough.
My SouthBend Hvy 10 is 1hp. I don't ask for much from it.
All 3ph.

KJ
 
When buying a phase converter I would err on the big side. You can always run a small motor on a big converter but the opposite isnt true. I bought a 5hp unit and wish I would have gotten the 7.5 or maybe even the 10. I came accross good deal on a cnc mill and my converter was not quite big enough.
 
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