Section 16.1: Single-Phase Induction Motors cont.
Electrical Method(s) cont.
In the split-phase motor, the starting winding is designed for high resistance (thin wire) compared to its reactance (RST >> jXST) so that:
ZST = RST + jXST » RST = RST/0°
The running winding is designed to have the opposite impedance properties, namely RRUN << XRUN (thick, low-resistance wire) so that: ZRUN = RRUN + jXRUN » jXRUN = XRUN/90°
Then since the two windings are supplied from the same voltage source, it follows that the two winding currents will be 90° out of phase with each other