Wednesday, December 5, 2012

Three Phase Motor as Single Phase Generator

To get single phase electricity from a three phase motor being spun as a generator you'll need to add some oil filled motor run type capacitors.
Here is a more fully developed diagram:


Unknown said...

Dose this need synchronisation before connection to the grid? Single phase won't start a 3 phase motor so connecting to the grid while it's not running could be dangerous, and if it is running? massive current if it's not synced right?

Thanks millions for all the help!

Rob said...

Small (<10kW) induction generators will sync to the grid easily or they can be run up to speed as a motor and then the valve can be opened up. Or you can run them up to speed on water power and then connect to the grid through your inter-tie protection device.

Unknown said...

what about when using the C-2C circuit to convert 3 phase output to single phase? I have a 55kw 3 phase generator and am hoping to get around 45kw single phase to sell to the grid, My latest plan is to keep the capacitors shorted while the generator is getting up to speed so there is no excitation then release the short just microseconds before connecting to the grid, This should make sure everything is in sync and the 3 phase motor is spinning first

deadbreed1212 said...

Hello Rod.

I have a Miller 250G portable welder/generator (240ac/DC). It has a huge Multi-tap transformer and rectifier. My quest is to split the components and build a large 12vdc-240/120 converter for quiet power and strap the generator to my 705 chevy bus when I need to charge and run bigger eq. Generator is easy part but the inverter I am somewhat oblivious. Can you draw up a simple schematic with t-former, caps and mosfets etc? I dmt care if its squa
re, triangle, or

true sine wave. Just need inspiration if u can help. Thanx deadbreed1212

uipment or even a small arc welder. Puts out arc/mig nd tig AC or DC (ccv?) Plus 44

Admin said...

i want to know that if i have 3 phase a/c alternator l1- 240v l2 -240v l3 -240v output then how to convert into in single phase 240v in your diagram first the 2nd pase and 3rd phase connected with capacitor 2c what will be the value of capacitor and again 3ph to 1 ph c capacitor connected what will be value of capacitor and we can get only single phase output ?

Admin said...

i want to know that C capacity of capacitor and 2C capacity of capacitor in 3 phase alternator output

please revert thanks