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S5-Q127.) Instability in an Electronic Speed Control system is caused by which of the following:

a.) Over-damping or setting the gain too low
This will cause the speed control to react to slowly to changes in load.
b.) *Under-damping or setting the gain too high
Correct. Having the gain set too high causes the speed control to react to quickly to minor
errors. If it is high enough, it can cause the machine to oscillate out of control between full RPM
and idle.
c.) Utilizing feedback control instead of feed-forward control
Feedback control is the primary control strategy for closed loop speed control systems.
d.) Advancing the timing of the ignition too far
This has nothing to do with speed control.

S5-Q128.) When a generator is in parallel with a utility grid, which of the following does the engine
governor control?

a.) *Kilowatts produced
Correct. The governor is going to determine the output power of the engine which is a direct
function of how many Kilowatts can be produced.
b.) KVAR
The governor has no effect on reactive power.
c.) Generator output voltage
The voltage is a function of flux and poles.
d.) Engine speed
Engine speed is determined by what frequency is required. It is always 60Hz in the U.S.

S5-Q129.) There are three types of governors: Electronic, Mechanical, and __________.

a.) Pneumatic
Pneumatic would be another system to add to the machine since it would not be required for any other
purpose.
b.) *Hydraulic
Correct. Since there is oil pressure already, it is very easy to adapt to speed control. It is an
excellent force multiplier and very stable.
c.) Centrifugal
This falls into the mechanical category.
d.) DC servo
Not practical since it would have to be added for just that purpose.

S5-Q130.) Upsets in system actuators are inevitable. When such an upset happens the system can tolerate:

a.) Absolutely NO oscillations
This is not practical. The gain would have to so high, it would be unstable.
b.) Up to 10 before shut-down
The system shutting down is not an option. This would be catastrophic.
c.) *Minimal
Correct. Oscillations should always be kept to a minimum, but some can and must be tolerated
by the system.
d.) Uncontrolled
This is not practical. No system should be left to oscillate out of control.

Page 91 - EGSA Apprentice Certification Program Study Guide