phase convertor

[morpheus]

I've read a bit about phase convertors but ran across this today while browsing through the metalworking.com drop box:

Static_converter.txt

Here is a static phase converter I built for my Dad's 3/4hp Powermatic Bandsaw Model 143.

This is just for 1 machine, and involved 3 parts from Grainger: a timer, a capacitor, and a single pole contactor. Total cost was approx $50.

We tried to make the transition/upgrade seamless, otherwise said
- all the parts fit in the existing junction boxes
- there is no change to the starting procedure, just hit "start" button and go

Now it runs on 220v single phase with no problems reported.

Filenames
static_converter_1.jpg
static_converter_2.jpg
static_converter_2a.jpg
static_converter_3.jpg
static_converter_4.jpg
static_converter_5.jpg
static_converter_6.jpg
static_converter_7.jpg
static_converter_8.jpg
static_converter_9.jpg

if you go to the drop box (http://www.metalworking.com/DropBox/) you can see the pics named above.

So, what exactly is that guy doing and is it safe ?

it sure seems like more people would do what this guy did if it was that easy.

[Shade Tree Welder]

Static phase convertors work fine for light loads. For heavier loads you will need a rotary phase converter. Yes, what he did is safe if you have the knowledge or references to size the components correctly. I'm sure somebody on this site has built their own and would be willing to help you. I purchased the one in my shop, it works great and I got all the phone support I needed. I'm not an electrician.

The unit I purchased was from;

www.electram.com

It was a 5Hp model mainly for my lathe, I also run the bridgeport off it.

[Fla Jim]

I think rotorary's are the way to go. I've built a bunch of them. With a static, you need to derate the motor due to phase inbalance.
I've posted this picture before, but here's the one in the Magic Garage.
Here's the inside:

[Fla Jim]

Here's the outside:

[Franz]

Go ROTARY, it's far cheaper if you have access to a 3 phase motor. The nicest thing about rotary is that each additional motor on the system becomes an additive converter.

[chumly2071]

http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

seems to be a pretty good article on DIY ones.

Another option, if it is a motor type load and not a welder type load, is to use a frequency drive. several of the new ones on the market can be wired into single phase and output 3 phase. one benefeit is max torque at almost 0 rpm, and infinitley variable speed. I have a small one on my drill press that has a 1ph 110V input and a 230V 3 ph output. infinite spindle speed with "torque boosting" capability added by the drive. it senses when the motor is bogging, and works its magic to add an additional 50% torque for a few seconds. It also has built in, programmable overload protection for the motor you have it conected to.

I also used a less programmable unit to power the 3 ph hydraulic pump unit on my JD2 Bender Hydro conversion. I got the pump unit off of ebay, NIB for $99. no one had need for a 3 phase one that appeared to sell new for $500.

there are lots of drives on ebay for sale, usually. get the model numbers, go to the manufacturer's web site, and check for features and capabilities to see if a bargain can be had to run a 3 phase used equipment bargain in turn.