9905-798

Product Description

This model is part number 9905-798, a microprocessor-based Digital Synchronizer and Load Control manufactured by Woodward. This model is designed to be used in the paralleling, synchronizing, loading, and unloading of three-phase AC generator sets. 9905-798 does not have power factor control or process control functions, as it is one of the reduced upgrade level models in this Woodward series.

Woodward's 9905-798 Model has a WYE PT Configuration. It is rated for use in operating temps from –40 to +70 °C (-40 to 158 F) and storage temps from –55 to +105 °C (-67 to 221 F). Additional environmental specifications for the 9905-798 are:

• Humidity …... 95% at 38 °C
• Mechanical shock …... US MIL-STD 810C, Method 516.2, Procedures I, II, V
• Electromagnetic susceptibility …... ANSI/IEEE C37.90.2; ANSI C37.90.1-1989
• Vibration …... US MIL-STD 167, Type I

Built-in diagnostics; automatic generator loading and unloading; setup, metering, and diagnostic capability through a handheld programmer terminal; droop, baseload, and isochronous load control capability; and reverse power relay are just a few of the available functions.

A few of the load control features of the 9905-798 DSLC include:

• A frequency trimmer function for accurate frequency control in isochronous load sharing systems
• Simple load droop operation provides safe operation in parallel bus applications
• Adjustable load switch output with independent pick-up and drop-out points
• Load raise and lower inputs to adjust speed before synchronizing
• Voltage raise and lower inputs to adjust voltage before synchronizing

The 9905-798 offers either phase matching or slip frequency synchronizing. Actual slip frequency and breaker delay values are used to anticipate a minimum phase difference between generator and bus at actual breaker closure for both methods. There is an automatic dead-bus closure function on this control, where only one DSLC control is granted dead-bus closing permission through locking techniques over the communications network.

Additional synchronizer features include:

• Time-delayed automatic multi-shot reclosing
• Voltage matching
• Auto-resynchronizing
• Synchronizer timeout alarm

These features may be enabled or disabled during setup.