Which capacitor shall i use for 3 phase 5 HP pump? how?

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SUMMARY

For a 3-phase 5 HP motor pump, a start capacitor is required to initiate the motor's operation. The connection involves linking the start coil (designated as T) to one of the phase coils (R or S) through the capacitor, allowing the motor to start in a specific direction. Once the motor is running, the start coil can be disconnected, and the motor will continue to operate in the starting direction due to the differing impedance. The capacitor size must be determined based on the motor's specifications.

PREREQUISITES
  • Understanding of 3-phase motor configurations
  • Knowledge of start capacitors and their function in asynchronous motors
  • Familiarity with electrical connections and phase designations (R, S, T)
  • Ability to interpret motor specifications for capacitor sizing
NEXT STEPS
  • Research the specifications for start capacitors suitable for 3-phase 5 HP motors
  • Learn about the implications of different impedance in motor operation
  • Explore wiring diagrams for connecting start capacitors in 3-phase systems
  • Investigate the effects of capacitor size on motor performance and starting torque
USEFUL FOR

Electrical engineers, technicians working with 3-phase motors, and anyone involved in the installation or maintenance of motor pumps will benefit from this discussion.

ishwarb
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I'm using a 3 phase 5HP motor pump n want to use capacitor. Which capacitor should I use and how to connect it to all the three phases?
Please do needful
 
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Do you mean a start-capacitor for an asynchronous motor?

The phase coils are not symmetric, as the start coil is dimensioned for a smaller current. Call the three phases as for the coils R, S, T, where T is the starting coil. Connect R and S directly to the net, and T connected to e.g. R through the capacitor. The motor will start in one direction. Connect T to S through the capacitor, and the motor will start in the opposite direction.

When the motor has started, you may disconnect T. The motor will continue running in the starting direction, which is due to different impedance in the motor as to synchronous/counter synchronous direction.

The size of the capacitor will emerge from the specifications of the motor.
 

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