Study Refresher

Question 1

how is electrical PPE rated?

Answer 1

Hazard/Risk Category

Question 2

how is arc rating measured

Answer 2

Calories/cm sq

Question 3

how many levels of PPE are there for the Risk categories and what is the minimum PPE required for the levels of risk category?

Answer 3

1 = 4 cal/cm sq
2 = 8 cal/cm sq 
3 = 25 cal/cm sq
4 = 40 cal/cm sq

Question 4

name the 4 boundaries when working with exposed energized conductors or circuit parts

Answer 4

> arc flash boundary
limited approach boundary
Restricted approach boundary
Prohibited approach boundary

Question 5

describe the arc flash boundary?

Answer 5

The boundary where an employee would be exposed to a curable 2nd degree burn

Question 6

describe Limited Approach Boundary?

Answer 6

a shock protection boundary crossed by only qualified persons and not by an unqualified person unless escorted by a qualified person

Question 7

Describe Restricted Approach Boundary

Answer 7

a shock protection boundary crossed by only qualified persons and because of its proximity to a shock hazard requires the use of shock protection techniques and equipment when crossed

Question 8

describe Prohibited Approach Boundary

Answer 8

a distance from an exposed part which is considered the same as making contact with the live part

Question 9

Describe an arc flash?

Answer 9

an undesired electrical discharge or explosion as a result of an arc fault that travels through the air between 2 conductors or a conductor and ground.

Question 10

describe the live-dead-live test procedure?

Answer 10

• Wearing proper PPE, test your multi-meter on an energized circuit with similar voltage to that of the equipment that is about to be tested.
• Test the equipment circuit that is supposed to be de-energized
• Re-test the multi-meter on an energized circuit with similar voltage to insure the meter is still functioning properly

Question 11

explain true Power and how it is measured

Answer 11

true power is power dissipated in a load and is measured in Watts

Question 12

Explain Reactive Power and how it is measured

Answer 12

Reactive power is power that is absorbed and returned in load. It is Measured in Volts - Amps - Reactive (VARS)

Question 13

Explain apparent power and how it is measured

Answer 13

apparent power is the total amount of power in a circuit, both dissipated and absorbed/returned. It is measured in Volts-Amps (VA)

Question 14

what does VFD stand for?

Answer 14

Variable Frequency Drive

Question 15

Describe the purpose of a VFD?

Answer 15

To control the speed and torque of an AC motor by varying the voltage and frequency supplied to that motor

Question 16

Name the Primary components of a VFD

Answer 16

• A converter to convert the incoming AC voltage to DC voltage
• A filter to smooth out the DC voltage
• An inverter to convert the DC power into a simulated AC sine-wave that motor will accept

Question 17

what does UPS stand for?

Answer 17

Uninterruptible Power Supply/source

Question 18

Describe what a UPS is

Answer 18

It is the battery backup system that can supply emergency power to a load when the normal incoming power source is interrupted

Question 19

name the 4 primary components of a UPS system and explain their purpose

Answer 19

• STATIC BYPASS (a circuit intended to bypass the UPS system and supply utility power to the load if there is a failure to the UPS)
• RECTIFIER (two main purposes. To convert incoming power from AC to DC voltage and keep the batteries in the UPS charged)
• BATTERIES (supply power to the load in the event of a loss of power from its normal source)
• INVERTER (converts the DC power from the UPS system back to a usable AC power to be supplied to the load)

Question 20

what does STS stand for?

Answer 20

Static Transfer Switch

Question 21

what does ATS stand for?

Answer 21

Automatic Transfer switch

Question 22

describe what a STS does

Answer 22

It automatically transfers load for preferred power source to standby power source without interruption of server room load. Very fast switching with max delay of 5 msec.

Question 23

Describe what a ATS does

Answer 23

Automatically transfers a power supply from its primary source to a backup source when it senses a failure or outage in the primary source.

Question 24

what does BAS stand for?

Answer 24

Building Automation System

Question 25

what does a BAS do?

Answer 25

Designed to automatically control building equipment to maintain environmental standards.

Question 26

what does BTU stand for?

Answer 26

British Thermal Unit

Question 27

in refrigeration what is a Ton?

Answer 27

a unit of power. lt is the power required to melt or freeze one short ton of ice per day at 32 degrees F