# 3 Phase Motor Running on Single Phase Power Supply

Generally we all are know 3 phase induction motors are widely used in industrial applications. because induction motor are having simple construction , less maintenance low cost compared to other motors. three-phase AC motor uses 3 section ower provide (3 pH 220v, 380v, 400v, 415v, 480v etc.), however in some actual applications, we’ve got single section power provides solely (1 pH 110v, 220v, 230v, 240v etc.), particularly in home appliances

In the case to run the 3 section machines on single section power provides, there area unit three ways that to try to to it:

Three section motor

1.Rewinding the motor

#### I: Rewinding the motor

It has some works to try to convert three section motor work on one section power provide. Here can show you the way to convert three section 380v motor to run on single section 220v power provide.

Rewinding Principle

Before talking concerning the usage of 3 section asynchronous motor being born-again to figure on single section power provide, we must always justify the problem of creating single section asynchronous motor rotating flux, as a result of single section motor are often started solely when the institution of rotating flux. the explanation why it’s no initial beginning torsion is as a result of single section winding within the flux isn’t rotating however beating. In alternative words, it’s mounted in terms of the mechanical device. during this case, the beating flux of the mechanical device interacts with this within the rotor conductor cannot generate torsion as a result of there’s no rotating flux, so the motor can’t be started. However, the position of the 2 windings within the motor includes a completely different angle of house. If it tries to provide a distinct section current, the 2 section current includes a bound section distinction in time to provide a rotating flux. that the single section motor mechanical device mustn’t solely have a operating winding, however additionally should have a beginning winding. consistent with this principle, we will use the 3 section winding of the 3 section asynchronous motor, and shift one in every of the winding coils with a electrical condenser or inductance, so the 2 section will bear a distinct current to determine a rotating flux to work the motor. once the 3 section asynchronous motor uses single section power provide, the facility is barely 2/3 of the first.

Rewinding Method

To use three section motor on one section power provide, we will connect any two section winding coils asynchronous, so connected to the opposite section. At now, the magnetic flux within the 2 windings have a section distinction, however the operating winding and beginning windings area unit connected to constant power provide, that the current is that the same. Therefore, connect a electrical condenser, inductance coil or resistance to the beginning winding asynchronous build this have a section distinction. so as to extend the beginning torsion on the affiliation, associate degree autotransformer are often accustomed increase the only section power provide voltage from 220v to 380V, shown in Figure one.1.

General small motors are Y connection. For the Y-type three phase asynchronous motor, the capacitor C winding terminal connects to the autotransformer starting terminal. If you want to change the shaft rotation direction, wire it as Figure 2.

General little motors area unit Y affiliation. For the Y-type 3 section asynchronous motor, the electrical condenser C winding terminal connects to the autotransformer beginning terminal. If you wish to alter the shaft rotation direction, wire it as Figure two.
Convert three section motor to single section 220v
If you are doing not need to extend the voltage, the 220V power provide will use this too. as a result of the first 3 section 380V power provide voltage winding is currently used for 220V power provide, the voltage is just too low, that the torsion is just too low.

Figure three wiring torsion is just too low. If you wish to extend the torsion, you’ll connect the phase-lock electrical condenser to the two-phase winding along within the coil and use this because the beginning winding. one coil directly connected to the 220V power provide, see Figure four.

In Figure three and four, if you would like to alter the shaft rotation direction, you’ll merely amendment the end-to-end direction of beginning winding or operating winding.

The moment of a magnet when {the 2|the 2} windings area unit connected asynchronous (one of that may be a reverse string) consists by two angles of 60° moment of a magnet (Figure 5). The moment of a magnet is far more than those of 120° moment of a magnet (shown in Figure 6), thus Figure five wiring beginning torsion is larger than Figure vi wiring.

The value of the access resistance R (Figure 7) on the starter winding ought to be closed to the mechanical device winding section resistance and may be ready to face up to the beginning current, which is 0.1-0.12 times of the beginning torsion.

Selection of Phase Shift capacitor

Working electrical condenser c=1950×Ie/Ue×cosφ (micro-law), Ie, ue, cosφ is that the original motor rated current, rated voltage and power laps.
General operating electrical condenser employed in single section power provide on the 3 section asynchronous motor (220V): every 100W use four to six micro-law electrical condenser. The beginning electrical condenser are often selected  consistent with the beginning load, typically one to four times of the operating electrical condenser. once the motor reaches 75%~80% of rated speed, the beginning electrical condenser ought to be disconnected, otherwise the motor can give way. Increase torsion for 3 section motor running on single section power