1. Circuit Analysis

2. Pure Resistance Circuit0º
90º
180º
270º
360º
VOLTAGE
CURRENT
POWER
E and I are In-Phase
Power Factor = 1.0

3. Pure Inductance Circuit0º
90º
180º
270º
360º
VOLTAGE
CURRENT
POWER
I Lags E and are Out-of-Phase by 90o
Power Factor = 0.0

4. Pure Capacitance Circuit0º
90º
180º
270º
360º
VOLTAGE
CURRENT
POWER
I Leads E and are Out-of-Phase by 90o
Power Factor = 0.0

5. Inductance & Reactance
The out-of-phase condition between voltage and amperage
Reactance:
The resistance voltage encounters when it changes flow
Inductive reactance:
A combination of inductance and reactance
Necessary for the starting and running of an induction motor

6. Inductive Reactance Induction: When voltage leads current Reactance:0º
90º
180º
270º
360º
VOLTAGE
CURRENT
Reactance:
The resistance encountered during the change of flow

7. MOTORS

8. Motor – Main Winding ONLY0º
90º
180º
270º
360º E Im

9. Motor – Main + Start Winding0º
90º
180º
270º
360º E Im Is
Split Phase Motor

10. © 2005 Refrigeration Training Services - E1#2 AC and DC Current v1.2
Capacitive Reactance
Capacitors can create an out-of-phase condition between voltage and amperage
The voltage lags behind the amperage
Capacitors increase motor starting torque
© 2005 Refrigeration Training Services - E1#2 AC and DC Current v1.2

11. Motor – Main + Start Winding PLUS Start Capacitor0º
90º
180º
270º
360º E Is Im
Capacitor Start Motor

12. Motor with RUN Capacitor ONLY0º
90º
180º
270º
360º
E and I are CLOSE or In-Phase
Power Factor = to or close to 1.0
What type of motor?

13. The End