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phase inverters pros and cons1/30
I am looking at a 16 inch radial arm saw that is 3 phase I need an inverter don't know anything about them any help appreicated
If you are trying to run a 3-phase machine from a single phase power source you are looking for a 'phase converter'. Inverters produce AC power from DC power.
Everything you need to know about phase converters should be available on the internet or at your local library.
Best of luck,
The easiest way to do it is with a VFD... it can take single phase 220vac input and put out three phase 220vac... there are many available.. Go to bing or ebay and search for VFD.. just get one that will handle the HP of your saw...
On 3-phase, be sure your saw is turning in the correct direction BEFORE putting a blade on it... if it is turning in the wrong direction, simply swap any two of the hot wires to correct the rotation of motor...
You should be able to get one for less than $200...
You can also use a "Rotary Phase Converter" which is a motor/generator to develop three phase but is more expensive..
Also you can buy a "Static Phase Converter" but it will reduce the HP of your saw by 1/3.. ie, a 3HP saw will only develop 2HP...
The best was I have found is with a properly sized VFD..
I'd be surprised that you could get a VFD for that saw for less than $200. I guess we don't know the motor size, but a 16" radial arm probably is at least 3 hp, probably 5. You might be able to get a Chinese VFD for that money, but I sure wouldn't trust those.
eBay mostly... quick search shows item 221668300083 is a used Toshiba, good brand... from 100% seller.. no affiliation, etc
A used working unit will probably last a long time as failures are within a short time frame of manufacture usually..
There are also new units (from China) in the $200 range...
Sold a 16" Dewalt RAS several years ago with a Chinese VFD and still working...
Only problem with VFD is you need to turn saw off/on via the VFD and keep motor wired to the VFD direct... however this also provides electronic braking to the saw also...
I looked that one up "eBay mostly... quick search shows item 221668300083 is a used Toshiba, good brand... from 100% seller.. no affiliation, etc" and it's a 3 phase in. I need single phase in. I'm just nervous about getting support or early hour failure on the Chinese VFD and likely difficult customer service. Sounds like your experience is positive, I've just read a lot of the opposite on metal working forums.
ALL VFDs are 3 phase in, 3 phase out.. but they work with single phase also.. you have 3 input power lines.. pick any two and apply 220vac and you will get 3 phase out... they take the input, rectify it (change it to DC), then generate 3 phase AC output... study the different forums to learn how they work..
One more question EC. Do you oversize the VFD if running on single phase in? I've seen folks talk about at least 50% over rating. Like at least a 7.5 hp rated VFD for my 5 hp motor. Do you agree with that? Thanks for helping out!
It is a good idea especially if you will be using the full HP... The current on the input lines is greater on single phase so yes..
However, on the saw I had, it never came close to operating at the full HP as I used it to cut boards, etc to length and had a 5HP VFD on a 5HP motor and never had a problem..
But to be safe, Yes, put in a 50% greater vfd than motor...
If using it for a saw, then make sure it is set to run for full speed all the time..
If using it on a lathe, it is great to change the speed as needed.. put one on my old Powermatic lathe and it is so much nicer to be able to turn a knob instead of changing belts... same thing for drill press's
Also, on any equipment I always use the remote on/off function of the vfd so I can mount a switch on or very near the equipment in use for safety reasons..
what is a vfd
Please see this link...
They are also a convenient method to go from single phase power to 3 phase power..