Chapter Two Exam

Question 1

Power supplies are selected by process only without consideration of material type and thickness. (True/False)

Answer 1

false.

Question 2

The severity of an electric shock depends principally on: (Multiple Choice)

Answer 2

magnitude of the current and part of the body through it passes.

Question 3

What is the purpose of an inverter?

Answer 3

DC to high frequency AC.

Question 4

Transformers designed for higher frequencies require much less iron core and windings than those designed for low frequencies. How is this frequency created?

Answer 4

using the inverter to principle to create high frequency Ac.

Question 5

An advantage of inverter based power sources is that the circuitry is more simplified than the conventional transformer-based power source. (True/False)

Answer 5

false.

Question 6

Inverter welding power sources are typically used for the pulsed GMAW process because:

Answer 6

output can be changed less than 1/40000 of a second

Question 7

When the core of a welding transformer is moved to adjust the output, this type of control is called a:

Answer 7

saturable reactor

Question 8

Inverter based power sources are usually heavy and bulky. (True/False)

Answer 8

false

Question 9

Inverter welding power sources have a very short response time because: (Multiple Choice)

Answer 9

inverter operates at high frequencies

Question 10

Power sources that use pulse technology suffer from inductance in the welding circuit affecting precision and sharp pulses of current. What measures should be taken to obtain the best result?

Answer 10

keep output cables as short as possible.

Question 11

What two components are used for microprocessor control?

Answer 11

transistors and electronic ampliifiers.

Question 12

A multi-process welding power source has the following features:

Answer 12

all of above

Question 13

Select the incorrect statement.

Question 14

What are the possible causes if the arc stops and starts during welding?

Answer 14

duty cycle to high, machine overload.

Question 15

Is the dirt inside a power source likely to create a short circuit?

Answer 15

yes

Question 16

Why is a transformer used as a power source for welding ?

Answer 16

provides low voltage and high current

Question 17

Does Ohm’s law apply to the welding arc?

Answer 17

no

Question 18

Gases are not normally electrically conductive. To start an arc requires:

Answer 18

high voltage

Question 19

Examples of insulators are:

Answer 19

rubbers, plastics, and ceramics

Question 20

Which of the following statements is correct regarding the open circuit voltage (OCV) for GMAW and SMAW.

Answer 20

Open circuit for SMAW is higher than GMAW

Question 21

The self regulating arc created by a constant voltage power supply is most commonly associated with a constant speed wire feeder. With this type of equipment:

Answer 21

When arc length increases, wire speed increases.

Question 22

What type of power source uses a voltage-sensing wire feed system to produce a stable self-regulating welding arc?

Answer 22

CC

Question 23

With real constant voltage sources, the voltage drops as current draw increases. For welding sources this is usually no more than:

Answer 23

Cv power source

Question 24

With real constant voltage sources, the voltage drops as current draw increases. For welding sources this is usually no more than:

Answer 24

20volts or so for 100 amperes of output current draw

Question 25

With the GMAW process and a CV power source, the welding current is determined by:

Answer 25

wire speed

Question 26

GTAW and PAW power sources are commonly designed with high frequency units. What does the high frequency unit do?

Answer 26

balances current flow