Trying to have an idea on the 3 phase system ( mainly motor application )

[BGAmodz]

HELLO EVERYBODY.

I am right now doing some studies on the 3 phase systems and mainly motors using that and it seems really complex compared to mono-phase systems ( to me at least ) .

So since am just studying this at home i only have single phase system , but some friends told me that its possible to add 2 other phases using an AC capacitor configuration .

What calculation should i make to choose the right capacitance value with the possibility to have a COS fi closer to 1 ?
Why the motor i got is called asynchronous type ?

Am on a 230 VAC line and this is the motor's data :

D : Delta configuration
Y : Star configuration

Operating voltages :

50 Hz -D/Y : 230v/400v - 0.25 Kw
60 Hz -D/Y : 275v/480v - 0.25 Kw

Operating currents :

50 Hz-D/Y : 1.4A/0.83A
60 Hz-D/Y : 1.4A/0.82A

- COS fi : 0.73/0.7

- 1320/1660 min^(-1)

Resistance of each bobbin :
51 ohms

 

[4pyros]

You could use a transformer to get three phase in high torque applications.

You can run a small (personally had good results up to 0.75kW) 3-phase motor on a single phase net by simply adding a running capacitor.

C = 70 x kW (formula for 230/400V 50Hz 3-phase motors to run on a 230V 50Hz single phase supply)

For example a 0.37kW motor would require a 25µF cap.

You'll have to keep in mind that starting torque drops dramatically, but for pumps or other low starting torque applications it is a simple and effective solution (so forget about running an 3-phase air compressor).


See if this helps;

 

[BGAmodz]

Thanks i will look for a cap ,but will i still notice a differnce when i change from star to delta ? i guess star should have less current than delta configuration

 

[4pyros]

Thanks i will look for a cap ,but will i still notice a differnce when i change from star to delta ? i guess star should have less current than delta configuration

This will not work on a star configuration, It must be delta to get the cap trick to work.