Revision Unit 5

Calculate the distance from the supply end of the circuit to the load center.

• 103.75 feet

• 77.5 feet

• 90 feet

• 270 feet

The middle of a group of receivers symmetrically arranged which are all of the same output is called_________.

• the middle center

• The load center

• the gravity center

• the center

Calculate the distance to the load center L of a two-wire single-phase circuit containing 8 lamps, the total length from supply to the end of the branch = 180 Feet, the distance between each lamp is 7 feet and the load for each lamp is 1.25 A

• 68 feet

• 86 feet

• 139.125 feet

• 186.5 feet

Power factor (PF) is the ratio of the __________ to the _____________  

• watts, volt-amperes

• volt-amperes, watts

• watts, volt-ampere-reactive

• volt-ampere-reactive, watts

As the load on an induction motor increases the power factor will_______

• remain the same

• increase

• decrease

• fluctuate

Upon which of the factors the voltage drop depend

• a.       Power factor of the load, Inductance, capacity and increased resistance of the circuit to alternating current.

• a.       capacity and increased resistance of the circuit to alternating current.

• a.       Cross section area and resistivity of the conductor

• Only Power factor of the load

Maximum-demand present load

An apartment in a multifamily dwelling has a total floor area of 900 ft². It is not equipped with an electric range. It has a small appliance load of 3000 VA.  Determine the maximum-demand present load for a two-wire 120-V feeder supplying the apartment.

• 47.5 A

• 32.87 A

• 30 A

• 20 A

Demand Factor for feeder and mains

An apartment in a multifamily dwelling has a total lighting load of 6000 VA and a small appliance load of 3000 VA. The apartment is not equipped with an electric range. Determine the maximum demand present load for a two-wire 120-V feeder supplying the apartment.

• 9000 VA

• 42.5 A

•      5100 A

• 75  VA

The FLC of a motor is:

• running current under full-load

• voltage at full load

• full-load horsepower permitted

• full-load amperes at locked rotor

Demand Factor for feeder and mains

Multifamily dwelling units have a total lighting load of 6,000 VA and a small appliance load of 8,000 VA. The apartment is equipped with an electric range rated 2500 kW. Determine the maximum demand present load for a two-wire 120-V feeder supplying the apartment.

• 51.25 A

• 77.91 A

• 73.75 A

• 137.5 A