Kohler 20-3250 kW manual Adjustment and Setting Specifications, Voltage Adjust, Frequency Setpoint

Set the PF adjust according to the requirements of the application. When a generator set will be connected in parallel with the utility, VAR or PF control should be ENABLED. If there are multiple generator sets in parallel as well, then reactive droop should be ENABLED also. Additionally, note that PF control should be used only while the generator set is connected in parallel with the utility. Parallel connection with the utility requires the logical indication that the circuit breakers tying the generator set bus to the utility bus are closed. This indication is made by use of the programmable digital input for VAR/PF mode. If this input function is activated, the excitation control changes to the selected VAR or PF control. If the logical indicator is not present and the VAR or PF control is not enabled, the control will not switch to VAR or PF control. Because the active state for the digital input is a HI or open connection, the default for the digital input (VAR/PF mode) is DISABLED (displays ENABLED NO). If the input is ENABLED by the user, it should be held low by a contact or jumper until the actual closing of the connecting circuit breaker(s). The proper control method, VAR or PF must be ENABLED within the regulator’s configuration menu.

Adjustment and Setting

Specifications

Voltage Adjust

The voltage adjust is entered as the rated or otherwise desired line-to-line voltage. The average of the line-to-line voltages is then regulated to the corresponding value as previously described. The setting may be as fine as tenths of volts. The voltage adjust defaults to the rated system voltage whenever the system voltage is changed. The voltage adjust may be set to any value within ±10% of the system voltage. The upper limit is ±10% above the system voltage and the lower limit is ±10% below the system voltage. If a value beyond these limits is entered, a RANGE ERROR message will be displayed.

As a reference, the present voltage adjust setting is displayed as well as the average value of the line-to-line voltages. The individual line-to-line voltages are also displayed on the subsequent menu screens. This allows the user to monitor any individual phase, if desired.

The voltage adjust setting may be changed by means other than the menu including user-defined digital input

or remote communications. If voltage adjustment occurs, the new value will be displayed accordingly in the voltage adjust menu.

Underfrequency Unload Enable

The underfrequency unload enable menu is used to turn the underfrequency unload on or off. A YES entry will turn the feature on and the display will show ENABLED YES. A NO entry will turn the feature off and the display will show ENABLED NO. The underfrequency unload defaults to an enabled (ON) condition.

Frequency Setpoint

The frequency setpoint is the cut-in point for underfrequency unloading. At any operating frequency below the frequency setpoint, the output voltage will be reduced. The frequency may be entered with resolution to tenths of a Hz. The range of acceptable entries is 30 to 70 Hz. Any entry beyond these limits causes a RANGE ERROR display and the setting will not change. The default value is one cycle-per-second (or two for non-ECM engines) below the normal system frequency. The frequency setpoint changes to the default value if the system frequency changes. A setting of 30 Hz essentially disables the underfrequency unload feature because most engines do not normally drop to speeds this low, even during load applications.

Underfrequency Unload Slope

The slope determines how much voltage is reduced during an unloading condition. The line-to-line voltage is regulated to a value less than the voltage adjust setting by this amount for every cycle below the frequency setpoint. The voltage may be entered with resolution as fine as one-tenth of one volt. The default value is 2.0 volts per-cycle-per-second. A zero entry for the slope in effect turns the underfrequency unload feature off.

Reactive Droop Enable

This menu allows the user to enable the reactive droop feature. A YES entry turns the feature on and the display shows ENABLED YES. A NO entry turns the feature off and the display shows ENABLED NO. Reactive droop is intended to be used in a generator set-to-generator set paralleling application.

206 Appendix TP-6200 10/12