ELE -508
LAB 2
Synchronous Capacitor
Preamble: All Synchronous Machines Because they are capable of power factor correction are rated in terms of
Reactive power KVA , MV A
When a synchronous motor is not used to drive a mechanical load but is used to provide a le adding PF It is
Called a Synchronous capacitor.
Equipment: 1) Synchronous motor
2) Three phase digital Power meter
Experiment: 1) Hookup the synchronous motor to the labvolt power supply as per your schematic developed
in the lab 1.
2) Start the synchronous motor as a squirrel cage motor, switch field on at 95% synchronous speed to
synchronize the motor with the power supply frequency.
3) Tabulate and plot KVA, KVAR, I phase versus IF for 10 steps of IF From min to max.
Note: the motor is run as Synchronous capacitor
Comments:
1) What value of field current yields a minimum line current Line current ?
2) What is the PF at the minimum Line current ?
Field
Current
KVA
KVAR
Phase
Current
POWER
PF
Calculated
PF
3)
Use Formula
Power = KVA * cos ()
To derive PF and compare this to measured value.
If the PF is different to the measured value explain why?
4) Why would you want to use the synchronous motor to PF correct,
instead of power factor capacitors?
5) What is the largest KVA the Synchronous motor has delivered or absorbed
in your experiment?
___--------------- KVA
Is this within rated value of the motor ?
What is the rated value of the Synchronous motor KVA ?