3 motors, how many capacitors needed?

[Puter2000]

I plan to use (3) three, 115 VAC, 1.4 Amps, 60 Hz. single phase motors together all running the same time and on the same circuit, these motors require a motor run Capacitor
20uF, 370 VAC, my question is, can I use one cap. for all
three motors, or will I need to use three caps. for three motors?

Puter2000

 

[SteveKW]

Each motor will need its own capacitor.

 

[aolalde]

A permanent-split capacitor motor, has the capacitor connected internally in series with a winding. The function of that capacitor is to modify the phase angle of the current circulating in such a winding. That capacitor is not intended for PF improvment.

For that reason each motor must bear a capacitor acording with the motor manufacturer specifications.

 

[powerjunx]

potz..

i agree to aolalde on its first and second line as he pointed out but not on "not for power improvement"

consider the internal winding of the motor:

capacitors in single phase motors are use for phase angle compensation of lagging power factor nature of inductive nature of the motor.. since it is lagging the capacitor is use to correct the angle of the machine to be near to the phase anlge of the source and doing so, it will start the machine smoothly without humming sound and stalling at running and starting respectively.

likewise starting a single phase machine without capacitor will impossible to run the motor except you displaced the phase angle thru manual shaft rotation.

since capacitor is use to modify the phase angle, it does improve the power factor because power factor is dependent to the phase angle ..cosine theta.

Potz., the idea you mention is applicable for power factor improvement of the whole system where the three machine were connected.. but never usable on individual machine having only one common capacitor.

thus, use capacitor for individual motor as steeve stated.

regards..

 

[jbartos]

Suggestion: Theoretically, it is possible; however, practically, it will be hard to implement and maintain working well since there are several variables to be synchronized, e.g. each motor will have to have the same parameters, the same loads and their character, etc.