Speed Modes Of Operation

The user can select through the panel’s mode switch either “Idle,” “Manual,” or “Auto” (Run) mode for the Governor. Additionally, Auto mode can be setup to function in various ways. A description of each control mode is provided below.

Idle

When the panel’s mode switch is in Idle, the Governor will hold the engine at the user-specified idle speed. This speed is specified during governor setup, described on another page. Note that the engine might be forced to run idle speed during an idle hold condition even if the switch is not in the idle position.

Manual

When the panel’s mode switch is in Manual the Governor will hold at a fixed manual speed. Whenever the switch is switched to Manual, the manual speed will start at whatever speed the engine is currently operating at and from there the user can use the panel’s speed switch to increase or decrease the speed. This mode is intended to be used only temporarily.

Note: If the mode switch is in Manual when the engine is started, the manual speed will start at the idle speed.

Note: If the mode switch is not at Manual, then the “Speed+ / Speed-” speed switch will have no effect.

Auto

The Auto setting is used for normal run operation of the engine. The behavior of the Governor in the Auto setting can currently be set to one of three ways, described below.

Note: When switching between operating modes (Idle, Manual, or Auto), the Governor will ramp more slowly than it would during normal operation.

Auto – Control to Fixed Speed

For a fixed speed setpoint, the Governor will hold the engine at a specified run speed. This run speed can be adjusted in governor setup.

Auto – Control to Suction Pressure

For a suction pressure setpoint, the engine will increase speed when the suction pressure is too high and decrease speed when the suction pressure is too low. The user specifies some operating range for RPMs during this mode. This mode is useful for cases where the incoming pressure varies, such as a low-producing well. Decreasing the RPM when the pressure drops gives the supply a chance to replenish. This can result considerable fuel savings and reduction of engine wear by eliminating wasted work by the engine.

Auto – Control to Discharge Pressure

For a discharge pressure setpoint, the engine will increase speed when the discharge pressure is too low and decrease speed when the discharge pressure is too high. Overall, this keeps the discharge at a constant rate. This mode can be used when the supply pressure is unconstrained, but the outgoing pressure is desired to be constant.