The document discusses electronic speed governors, which are devices used to measure and regulate the speed of engines or machines. It provides details on: - How speed governors maintain a constant engine speed by controlling fuel supply based on feedback to compensate for changing loads. - The PID control loop that automatically adjusts fuel flow to keep speed at the desired setpoint. - Speed droop and isochronous control modes that allow generators to run in parallel and share loads proportionally. - Magnetic and electronic components that sense engine speed and convert it to an electrical signal for the controller.

1. ELECTRONIC SPEED GOVERNOR
A governor, or speed limiter, is
a device used to measure and
regulate the speed of a machine,
such as an engine
By
J.Majumder Chartered Engineer MIE

2. SIMPLE EXPLANATION OF WORKING OF GOVERNOR
• Speed Governor is an electromechanical device in diesel engine.
• Its function is to maintain & control the speed of the engine by
controlling the amount of fuel to engine. The core concept in
power generation is that, the speed of engine or turbine must be
constant or +-x of it. A fluctuation in speed would cause
fluctuation in voltage and frequency.
• Governor maintain the speed of running engine by controlling the
amount of fuel supply to engine. If the speed is low or high other
than nominal value, then it increase or decrease the amount of
fuel to engine. The signal governor receives from a certain control
system.

3. THE SPEED SET POINT ON THE ROAD IS 100 KM/H AND
MAINTAIN THE SPEED BY THE ACCELERATOR DEPENDING
OF DRIVING UP-OR DOWNHILL.
Governor
Governor

4. INCREASED LOAD
100
The car starts up the hill,
load increases, speed
decreases.• The actual
speed is less than desired
speed.• Driver increases the
fuel to increase the speed,
which returns the actual
speed to the desired speed.•
Before the actual speed
reaches the desired speed,
the driver reduces the fuel to
prevent overshoot of speed.
This is called Compensation
and is adjusted to match the
response time of the prime
mover.• It takes more fuel to
pick up load than to maintain
load

5. DECREASED LOAD
100
The car starts down the hill,
load decreases, speed
increases.• Actual speed is
greater than desired speed.•
Driver decreases fuel to
decrease speed, which
returns the actual speed to
desired speed.• Before the
actual speed reaches the
desired speed, the driver
increases the fuel to prevent
overshoot of speed. This is
called Compensation and is
adjusted to match the
response time of the prime
mover.

6. CONTROL LOOP OF A DIESEL ENGINE
The governor functions
the same as the car
driver.• It automatically
changes the Fuel Flow to
maintain the desired
speed or load.

7. ELECTRONIC SPEED GOVERNOR
When used as an
automatic control system
for operation or process in
which feedback in a
closed path or group of
paths to maintain output
at a desired level.• If
parameter(s) of the loop
change, it will effect the
entire loop and fuel will
automatically be
corrected to maintain the
desired setpoint.

8. GOVERNOR PID CONTROLLER
How Much
How Long
How Quick

9. RESPONSE OF PID CONTROLLER

10. PID CONTROLLER
The main task of the governor controller is to convert the induced frequency read
by the MPU into a DC voltage signal and then compare it with setting voltage
(frequency). The result will be calculated by PID and then finally be output to
actuator

11. POSSIBLE OPERATING MODES
• Speed droop especially used at infinite grid
parallel operation
• Isochronous load sharing especially used at
island operated plants
• Master / Slave load sharing especially used at
ships propulsion plants, running two engines on
one shaft

12. DEFINITION OF SPEED DROOP
Droop is simply a decrease of the speed setting value with
governor power piston (output shaft) movement in the
increase fuel direction
Governor Applications:
•Grid parallel operation
•Load sharing between two ships main engines running on one shaft
Master/Slave)
•Load sharing at Diesel electric plants on ships Speed
In electrical power generation, Droop Speed Control is a speed control
mode of a prime mover driving a synchronous generator connected to
an electrical grid. This mode allows synchronous generators to run in
parallel, so that loads are shared among generators in proportion to their
power rating.

13. WHY SHOULD YOU USE DROOP CONTROL?
Suppose that a generator is paralleled with the utility grid. If it is
considered as an infinite bus, the utility grid will determine the
generator frequency (speed) and voltage. When the speed (and
frequency) setpoint is slightly lower, the speed governor will fully close
the fuel supply in attempt to lower the frequency. Is the setpoint
slightly higher, the speed governor will fully open the fuel supply. For
the automatic voltage regulator and the reactive power something
similar happens. To solve these problems, we use droop controls.

14. SPEED DROOP CURVE

15. CALCULATION OF SPEED DROOP
if the turbine is rated at 3000 rpm, and the machine speed
reduces from 3000 rpm to 2880 rpm when it is loaded from
no load to base load, then the droop % is given by
= (3000 – 2880) / 3000
= 4%
If all engines in a droop system do not have the same droop setting, they will not
share loads proportionally with the same speed settings. If the system load
changes, the system speed/frequency will also change but the percent of load on
each engine-generator set will not be changed proportionately.

16. GENERATOR LOAD SHARING

17. GENERATOR LOAD SHARING

18. GENERATOR LOAD SHARING
If Gen #1 Droop is a % and Gen # 2 b % and
total load X
Then Load taken by #1 Gen = X . a / (a+ b)
Load taken by #2 Gen = X . b / (a+ b)

19. ISOCHRONOUS GOVERNOR
CONSTANT SPEED No change in speed setting
with an change in load
Applications:
•Grid parallel operation for frequency stabilization
•Load sharing at Island Power Stations

20. ISOCHRONOUS GOVERNOR

21. ISOCHRONOUS GOVERNOR

22. LAYOUT MASTER /SLAVE OPERATION

23. ELECTRONIC SPEED GOVERNOR

24. SPEED PICK UP

25. SPEED PICK UP
F = number of teeth × engine speed (RPM) / 60.
This frequency is proportional to the engine
speed.

26. SPEED PICK UP

27. MAGNETIC SPEED PICK UP

28. ELECTRONIC SPEED GOVERNOR

29. LOAD SHARING DIAGRAM

30. ADJUSTMENT OF ELECTRONIC GOVERNOR
Ramp Time can be set from 3 up to 20 seconds. The
Ramp Time is the length of time from IDLE to the rated
Run Speed.
Droop operation is obtained by setting the Droop
potentiometer. Moving Droop Pot clockwise increases the
Droop. The amount of Droop for a given setting
If GAIN or INT. (Integration) is over adjusted, it causes the
engine speed to oscillate. Repetitively increasing and
decreasing the GAIN and INT. arrangement can help to
obtain the best performance.