Building Automation LESSON 2

Question 1

List three types of secondary power source

Answer 1

1. Engine generators
   2 gas turbine generators
2. Uninterrupted power supplies
3. Fuel cells

Question 2

Name two critical electrical loads which are required by governing entities to have secondary power sources

Answer 2

1. Egress lighting

2. Fire pumps

Question 3

What percentage of electricity is produced from nuclear power?

Answer 3

19%

Question 4

____are the most commonly used source of secondary power.

Answer 4

Diesel generators

Question 5

What is the last point on the power distribution system for the power company?

Answer 5

A switch board

Question 6

____is the amount of electrical power drawn by loads at a specific moment and is measured in_____.

Answer 6

Electrical demand, KW

Question 7

The measure of how closely the power in an electrical system matches the nominal characteristics is called____

Answer 7

Power quality

Question 8

Power quality is influenced by the____, as well as electrical loads operating on the system.

Answer 8

Performance of the generating/ distributing equipment

Question 9

What are the most common power quality parameters that are controlled by an automated system? (3)

Answer 9

1. Voltage
2. Current
3. frequency

Question 10

List three common causes of voltage sags.

Answer 10

1. Overloaded transformer
2. Undersized conductors
3. Conductor runs that are too long
4. Too many loads on a circuit

Question 11

What are voltage swells caused by? (3 things)

Answer 11

1. Loads near the beginning of a power distribution system.
2. Incorrectly wired taps
3. Large loads being turned off

Question 12

What are common causes of transient voltages?

Answer 12

1.Lightning strikes
2 unfiltered electrical equipment
3. Contact bounce
4. Arcing
5. High current loads being turned on and off

Question 13

Name the two main functions of control devices in electrical systems

Answer 13

Monitoring and maintaining reliable quality

Question 14

List the common measurements that are taken by power quality sensors

Answer 14

1. Voltage
2. Current
3. Unbalance
4. Frequency
   5 harmonics
5. Noise

Question 15

A ____is a heavy duty relay for switching circuits with high- power loads.

Answer 15

Contactor

Question 16

What type of motor controller is used to change the speed of an AC motor by changing the frequency of the supply voltage?

Answer 16

A variable frequency drive

Question 17

A variable frequency drive can control? List all that apply

Answer 17

1. Motor speed
2. Acceleration time
3. Deacceleration time
4. Motor torque/ braking

Question 18

What type of switch allows an electrical system to be switched between two power sources?

Answer 18

Transfer switch

Question 19

Why is it important for a distributed generator to immediately disconnect from the grid if there is an outage?

Answer 19

The secondary power system could backfeed and damage equipment

Question 20

What are the most common designs of UPS systems?

Answer 20

1. Standby
2. Line interactive
3. Rotary
4. Double conversion online
5. Delta conversion online

Question 21

What type of UPS system has high efficiency, small size, and is lower cost than other UPS systems?

Answer 21

Standby