Capacitor Bank Installations Flashcards

1
Q

Why is a capacitor bank installed?

A

To correct the power factor of various inductive loads, and reduce the demand on the line.

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2
Q

When sizing feeders for capacitor banks what must be considered?

A

The wires should be sized to handle at least 135% of the total rated load of the bank.

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3
Q

How long may tap conductors be?

A

7.5 m. after this, they will be the same size as the feeders and not be considered a tap.

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4
Q

What is the maximum size overcurrent protection for a capacitor bank?

A

250% of the rated load of the bank. If it does not match an O/c value, then round down.

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5
Q

Does a capacitor produce significant heat? How does this affect how they are mounted?

A

Almost no heat as they are nearly entirely reactive. They can be mounted in a variety of ways as they do not pose a fire hazard under normal operating conditions.

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6
Q

Capacitors must have a discharge circuit, what are the requirements for 750 V or less circuits and more than 750 V circuits?

A

750 or less = cap must drain to 50V or less in 1 min,

more than 750 = cap must drain to 50V or less in 5 min.

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7
Q

May motor windings be used as a discharge resistor?

A

Yes, if there is no disconnect between the capacitor and motor.

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8
Q

If a capacitor bank is mounted on the line side of a motor, what is one important consideration?

A

When the motor is shut down the capacitor will provide leading vars to the rest of the system.

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9
Q

When a capacitor bank is connected on the load side of a motor controller, what is a very important consideration?

A

The overload devices must be resized as the line current will be less.

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10
Q

Where is the lower current obtained from power factor correction evident?

A

only on the line side of the capacitor bank.

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11
Q

What considerations must be taken in the installation of a capacitor bank disconnect?

A

It must be within sight and not more than 9 m, unless capable of being locked open.

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12
Q

If an enclosed type contactor is used to disconnect a capacitor circuit, what must it be rated for? Otherwise what must the disconnect be rated for?

A

150% of the capacitor load (enclosed type contactor),

Otherwise 135% of the capacitor load.

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