Is the voltage you are applying to the motor 415V 50Hz? If so, the motor has a problem or the load is to much. Applying capacitors will not lower the amperage the motor requires. Capacitors will lower the amperage on the conductors feeding the motor.

Supporting wareagle ….

The capacitor bank is used not to improve the P.F of motor itself; it is used to improve the P.F of the system. Even you add the capacitor bank at the motor terminal; it will reduce the current through the motor cable but not the current (of course the magnitude of the current) drawn by the motor. What is the S.F (Service Factor) of the motor? If it is less than 1.15, 420A can damage the motor, however, I would suggest you contact the motor manufacturer and find out how long the motor can sustain for 15%-20% overload and take the decision.

-MS

Obviously, 10 years.

If its 10 years, then why worry?

Are you saying that the motor/pump produces too much pressure?

If you are saying this, reducing the motor current will not solve your problem. As a matter of fact, it sounds like your motor is working perfectly since you state its current (amps) usage for the past 10 years has been quite stable. If you reduce the motor current, you reduce its torque, which may cause other problems for you.

What you need is a Variable Frequency Drive but since the motor is at least 10 years old, it would only be advisable to use a VFD after the motor has been tested for faults - insulation resistance, voltage stress faults etc etc. Also, it is highly recommended that the motor have at least a "Class F" insulation before even considering connecting a VFD to it. Further, if the motor is "unenclosed" (has ventilation slots) & is 10 years old, it is highly advisable NOT to connect a VFD to this motor unless it has been fully tested.

Power Factor Correction will not reduce the current used by the motor.

If you want formulas, let that be your next question.

I'm curious...where are you & what is your job?

Caviat: this only applies to induction motors.

I'm not very knowledgeable about PF but, from what I know, it won't reduce the current consumption (as others have already said).

From experience, however,your motor seems seriously overloaded. If the motor's current consumption is over the FLA, and you're still not getting enough pressure, that tells me that your motor and pump are not matched. It would be best to obtain the required hp of the pump and buy the appropriate motor.

regards,

Vulcan

If you increase the power factor the efficient part of the consumed Amps will be lower so if you manage the reach the pf=1 your motor/capacitor_bank system will consume about 395 Amps.

<....still unable to get the required pressure....>

There could be loads of factors other than the motor. Try looking at these as well:

• Has the system been added to so as to create loads more parallel paths for the flow other than the original design ones over the last 10 years?
• Is the pipework clean inside, and not partially blocking the flow anywhere, particularly on the inlet?
• Is there a partially-open valve where there shouldn't be one?
• Is there a non-return valve on parallel pump sets that is letting a small reverse flow through, due to 10-year corrosion, or some foreign object wedging the port partly open?
• Is there a blocked strainer somewhere that is choking the inlet flow to the pump?
• Is the inlet connection of the pump fully flooded at all times while the pump is running?
• Is the 10-year-old pump impeller in good condition, with no wear or damage? What about the volute?
• Is the correct size impeller still fitted or has a get-it-going-again maintenance spare of the wrong size been fitted instead?
• Using the manufacturer's published performance curve for the pump, if the pressure is too low, is the flow too high? Whereabouts on the curve is the pump operating? Is this realistic?
• Is there a leak in the pipework somewhere that isn't currently being detected?
• Are their weirs on the system that would limit the delivery pressure of the pump regardless of what was tried to increase it?
• Is there a downstream valve that could be throttled to provide the required pressure, albeit at a reduction in flow?
• etc.