making a 3 phase rotary converter DIY

[Dan Gray]

VFD
Rotary
diode box rotary replacement.
there is a difference in power loss

Hey first be sure you know what happens to you if you touch 220 AC power and converted power before you attempt this..or you could very well be making knives for God him-self in the after life..

if you don't have 3 phase in your shop and want it, what do you do?
well the cheapest way and with little power loss in the conversion this would be it.. make your own

if you have 3 phase motors to spare ,you can use them to make 3 phase
the more you hook up in parallel the closer you come to true 3 phase

this is the same as a rotary converter but closer to true 3 phase

say you have 3 3 phase motors to play with all 2hp and
wired for 230-240 (low voltage) or the single voltage older type..

the first motor you will have to have a way to start it, you can even use a rope pull cord to start the motor or a 110 motor.. I'll sum up and re-cap on this....
the motors

hook up all the motor wires in parallel
from start motor #1 wire the
L1 L2 L3 leads
to motor #2 's
L1 L2 L3 and then the same
to motor #3
L1 L2 L3

now on motor 1
( be sure your supply 220 power is shut off)
hook up the 220 leads from your power box
to either of the three leads on this first motor it don't matter which

now unlike a reg rotary converter that you buy
that is self starting you have to get the first motor spinning once you throw on the 220 power. you can get inventive with that it don't matter how just start it turning..

once you start the first motor turning the rest will start..
the last 3rd motor will be the motor you are running your equipment with..
(( mind you that you can use just two motors but it would be = to a store bought rotary converter..with power lost ))

the fields in the 3 phase motors are converting 220 single phase into 3 phase
and the first two motors with basically no strain on them the power consumption is low.
and now you have a home made 3 phase rotary power converter..
for the price of maybe some used 3 phase motors that run cheap $'s.

you now have a 2 hp 3 phase power converter.

 

[Dan Gray]

hmmm no comments..
I must have explained this too well

 

[micad]

Dan,

Do a Google search on rotary phase converters. There's a wealth of info there. It's really late and I'm really tired or I'd find the link for you.
Basically what you are describing will work ok, but you are missing some important points.
With a 5 hp 3 phase motor as your 'source' you will have 5 hp of 3 phase available. Parallel another motor, say 3 hp, and now you have 8 hp available, and on and on.............
You need to use a bank of capacitors to get the starting torque and voltage/phase angle regulation.
Any way it's too late tonight (this morning, actually) to go into this, so I'll let you do the google search. The links I'm refering to are near the top of the first page of results (at least they are every time I search for them.

Just my .02.......

Mike

 

[Dan Gray]

Dan,

Do a Google search on rotary phase converters. There's a wealth of info there. It's really late and I'm really tired or I'd find the link for you.
Basically what you are describing will work ok, but you are missing some important points.
With a 5 hp 3 phase motor as your 'source' you will have 5 hp of 3 phase available. Parallel another motor, say 3 hp, and now you have 8 hp available, and on and on.............
You need to use a bank of capacitors to get the starting torque and voltage/phase angle regulation.
Any way it's too late tonight (this morning, actually) to go into this, so I'll let you do the google search. The links I'm refering to are near the top of the first page of results (at least they are every time I search for them.

Just my .02.......

Mike

thanks Mike I guess through the years I've lost some memory
and I didn't realize that ganging them up in Parallel added to the HP rating,though I was safe in realizing you had at least two HP..((I guess I confused
Parallel with inline ,, ))

are you saying the other motors in line won't start if the first source motor
is running?
I'll look at that site...TX