Describe a governor other than the ordinary flyweight type. How is it driven and how
does it control engine spend?
The electric governor, which is operated without a flyweight has proportional and reset action
with the added advantage of load sensing. With the governor small permanent magnet
alternator is used to obtain a speed signal from the engine.
The advantage of using permanent magnet is that there will be slip rings or bushing to wear. The
alternator generates voltage which determine the speed signal. This signals converted into DC
voltage by a rectifier. This DC voltage is proportional to engine speed. The DC voltage is then
sent to the amplifier and controller which also require a reference DC voltage of opposite
polarity from the speed setting unit. (This voltage is represented of the diesel operating speed
desired) These two voltages are connected to the input of an electric amplifier. If the voltages
are different, the amplifier is equal and opposite, they cancel and there is no change in amplifier
voltage output.
If the voltage is different, the amplifier sends a signal through the controller to the electrohydraulic
converter which via a servo -motor will change the fuel rack to lower or increase speed
as required. In order that the system is isochronous the amplifier controller has internal
feedback. The load sensing unit is included in the governor to correct the fuel supply to the
prime mover before a speed change occurs. The speed of response of the load sensing element
must be better than that of the speed sensing element which would be used to correct small
errors of fuel rack position.
The example of the electric governor the electric output of the main generator would be tapped
and it any load alternation took place on the main generator this would be synchronized and a
signal fed into the controller to order the electro-hydraulic converter (via the servo motor) to
increase or decrease engine speed by adjusting the fuel rack.
does it control engine spend?
with the added advantage of load sensing. With the governor small permanent magnet
alternator is used to obtain a speed signal from the engine.
The advantage of using permanent magnet is that there will be slip rings or bushing to wear. The
alternator generates voltage which determine the speed signal. This signals converted into DC
voltage by a rectifier. This DC voltage is proportional to engine speed. The DC voltage is then
sent to the amplifier and controller which also require a reference DC voltage of opposite
polarity from the speed setting unit. (This voltage is represented of the diesel operating speed
desired) These two voltages are connected to the input of an electric amplifier. If the voltages
are different, the amplifier is equal and opposite, they cancel and there is no change in amplifier
voltage output.
If the voltage is different, the amplifier sends a signal through the controller to the electrohydraulic
converter which via a servo -motor will change the fuel rack to lower or increase speed
as required. In order that the system is isochronous the amplifier controller has internal
feedback. The load sensing unit is included in the governor to correct the fuel supply to the
prime mover before a speed change occurs. The speed of response of the load sensing element
must be better than that of the speed sensing element which would be used to correct small
errors of fuel rack position.
The example of the electric governor the electric output of the main generator would be tapped
and it any load alternation took place on the main generator this would be synchronized and a
signal fed into the controller to order the electro-hydraulic converter (via the servo motor) to
increase or decrease engine speed by adjusting the fuel rack.
