Running 3ph Motor from single phase 2

[robmaint]

This may be a simple question so I would apreciate a simple answer, but I would be grateful for someone to explain how I can wire up a small motor. The motor in question is a small 240v delta/ 415v star motor and is only 1/3 HP.

 

[teco]

robmaint:-
the type of connection you require is called a steinmetz connection. you connect the motor in delta (230 volt)and a 25mf 250 volt cotinuous capacitor is connected across 2 legs of the delta bridge, the supply (phase)is then applied to the 3rd leg and (neutral)to one lead of the capacitor.to reverse direction of rotation inter change neutral with capacitor leads.
note:- for a 0.25kw 4 pole motor new current will be 1.7 amps , eff 64% locked rotor current ratio 3, locked rotor torque 0.5 and pull out torque 2 x rated torque.
as motor now only developes 50% starting torque it may not excellerate the load. this type of connection is only good for centrificl fans and pumps.
hope this will help.
kind regds.

 

[jbartos]

Assuming that your motor is three-phase type, it can be connected in the delta or star connection. The motor connection is selected on the basis of suitable system voltage availability. Please, notice that delta winding generally tend to have triplen harmonic circulated/cancelled within the delta connection. The star connection will not cancel the triplen harmonics; therefore they will propagate to the motor rotor and heat it. Many squirrel-cage induction motors are run in delta connection.

 

[robmaint]

Thanks for your responses it has been of help

kind regards

 

[BJC]

Before looking at transformers and whatever I would look at veriable frequency drives. You can get them with single phase input and three phase output.
Try Allen Bradley, Square D, Cutler Hammer GE etc. I think you may be looking at less than $500