Single to 3 phase conversion & motor tutorial.

[andycktm]

So the next time anyone looks on ebay and see's a wadkin 3 phase 3hp + 2hp
planer/thicknesser for £300 its £300 for a reason.
If its home use 3 phase conversion maybe your home insurance would want to know!

 

[Jamesc]

Hi Bob,

I think that what would be useful is some form of flow chart so that you could readily choose the best solution. For instance I'm much more into metal than woodwork and have recently aquired a mill with 4 3-phase motors all widely different capacities and two of them dual speed. I have concluded that a rotary converter or true 3-phase are the only ways to go. Am I correct?

Also can a static converter be converted to a rotary with the addition of a jockey motor? if so how do you select the size of motor.

Is this the sort of thing you are looking for?

Regards

James

 

[9fingers]

HI James,

Good to hear from you again. Your questions will certainly be on my list but multiple motors per machine and multi speed motors are rarely found on woodworking machines so I'll possibly not add this information in the early versions. Therefore I will try and answer this now for you.

Multiple speed 3 phase motors are quite restrictive when it comes to running from single phase.
For a start they tend to be separately star wound for each speed so there is rarely an option to re-wire to delta for a basic inverter although there are inverters appearing that convert to 415volt and provide variable frequency. At one time these were 'back street' modifications to basic inverters without manufacturer approval but approved designs are appearing now.

As soon as a machine has multiple motors then as inverters need to be dedicated to a single motor, the only way to go as you correctly state is real 3 phase or a converter. To get good performance with multiple speed motors a rotary converter is to be preferred.

Ideally the pilot motor should be bigger than the biggest motor you need to run. If the biggest motor is single speed then it is feasible to use this as the pilot for the others but I suspect your largest motor might well be the dual speed one.

Hope this helps

Bob

PS I'm still interested in that chuck when you have a chance to look it out.

 

[9fingers]

Well folks, the very first section of my motor ramblings is now in draft form and when my ISP deigns to restore access to my file storage space I'll upload it and post a link.
LOTS more to do to cover all the stuff you have asked for but it is a start.


Then you can tell me that I'm barking up the wrong tree etc etc!

Bob

 

[Jamesc]

Looking forward to reading it Bob.

James

P.S. I haven't forgotten about the chuck, it's just that the back of my workshop is sheeted over to protect all the machines from all this messy woodworking stuff and the chuck is somewhere near the bottom I think :lol: I hope to return to metalworking soon and will be in touch.