Governors

Question 1

What is the main purpose of a governor?

Answer 1

To control the speed of a prime mover.

Question 2

What do dirt and sludge in a governor’s housing usually indicate?

Answer 2

That it’s time to dismantle the governor and perform a thorough cleaning and inspection.

Question 3

How can the operating speed be adjusted in a simple mechanical governor?

Answer 3

by varying the compressive force on the spring

Question 4

A governor is meant to do one of these three things when controlling the speed of a prime mover under varying load conditions:

Answer 4

maintain the selected speed, limit the slow and fast speeds, prevent overspeed of the prime mover

Question 5

The series of steps in correct order that a governing system must perform to work properly are:

Answer 5

detection, transmission, correction

Question 6

What type of governor will maintain a constant speed without change?

Answer 6

an isochronous governor

Question 7

The condition where a governor causes and engine to speed up and slow down repeatedly is called:

Answer 7

hunting

Question 8

The governor characteristic that prevents hunting is called:

Answer 8

stability

Question 9

What problem will reducing the friction in a simple mechanical governor help correct?

Answer 9

dead band

Question 10

In most natural gas, propane, or gasoline engines, what does the governor actuate, and what does it operate off of?

Answer 10

The governor actuates the throttle valve, and operates off the engine vacuum.

Question 11

What does the governor on a diesel engine control?

Answer 11

the fuel rack

Question 12

What is the similarity between a variable speed control governor and a isochronous governor? What is the difference?

Answer 12

They both hold the driver at a steady speed, but the variable speed governor can be adjusted to any setting between the min and max speeds.

Question 13

What is the name of the specific governor characteristic that prevents hunting?

Answer 13

speed droop

Question 14

In a simple electric solenoid, what does the magnetic attraction cause the soft iron core to do in relation to the coil?

Answer 14

It causes the soft iron core to be pulled into the coil.

Question 15

What is the advantage of having three magnetic pickups to sense speed on a machine?

Answer 15

If one pickup quits working, the machine can still run as long as there is speed signal coming from the remaining two pickups. The malfunctioning pickup can also be worked on while the machine is running.

Question 16

At what speed do mechanical governors become unreliable, and electronic overspeed trips would be used?

Answer 16

speeds of 10,000 rpm and above

Question 17

On start up, before steam is admitted to the turbine, what position do the flyweights have?

Answer 17

they are held in close to the shaft

Question 18

What does the governor actuate on a steam turbine?

Answer 18

The steam valves to speed up/slow down the turbine.

Question 19

What are the three main concerns with simple mechanical governors?

Answer 19

cleanliness, lubrication, proper adjustment

Question 20

What is speed drift?

Answer 20

a gradual deviation in speed

Question 21

What is the purpose of the orifice in the amplifier piston in a hydraulic governor system?

Answer 21

To cause a pressure increase to the servo piston and subsequently a fuel flow decrease

Question 22

In what type of governing system in the governing function most clearly separated?

Answer 22

in an electro-hydraulic governor

Question 23

In a simple mechanical-hydraulic governor, what do the mechanical flyweights directly control to be able to adjust the speed?

Answer 23

the spool valve

Question 24

What do hydraulic governors sense a change in to make the speed governing system work?

Answer 24

pressure

Question 25

What will be the effect on flow of the hydraulic pump if there is an increase in speed of the prime mover?

Answer 25

there will be an increase in flow

Question 26

What is a major advantage of an electronic governing system?

Answer 26

easily adapted to remote operation

Question 27

How is a basic overspeed mechanical trip pin held in normal running condition?

Answer 27

the spring compression force is greater than the centrifugal force acting on the pin

Question 28

What normally activates a hydraulic overspeed trip?

Answer 28

a mechanically operated trip pin

Question 29

What’s considered a good recommended practice for storing spare governor parts for long periods of time?

Answer 29

Fill the hydraulic parts completely with oil or use desiccants to trap moisture.

Question 30

What are the two most common types of throttle valve governors?

Answer 30

automatic or vacuum, and centrifugal

Question 31

Why are electric load sensing governors used in electric power generating plants?

Answer 31

To maintain a stable frequency regardless of changes in load.

Question 32

If the flyballs are shown at their outermost position, at what speed is the shaft going?

Answer 32

high speed

Question 33

How does a hydraulic governor obtain variable speed?

Answer 33

By changing the size of the restriction in the needle valve.

Question 34

What two conditions could cause a turbine to overspeed?

Answer 34

a sudden loss of load, or governor failure

Question 35

How can oil condition affect relays, valves, and servo rams?

Answer 35

It can cause stickyness