Basler Electric DECS-100 - Manual (Page 26)

3-2 DECS-100 Functional Description 9287500991 Rev M
and conditioned before being applied to the input of the ADC. The voltage signal from phase C and A
(VC-A) of the generator is used by the ADC to calculate the rms value of generator voltage across phases
C and A. Likewise, the voltage signal from phase C and B (V
C-B
) of the generator is used by the ADC to
calculate the rms value of generator voltage across phases C and B. The rms value of generator phase B
to phase A voltage (V
B-A
) is calculated by the microprocessor from the phase C to phase A signal (V
C-A
)and
the phase C to phase B (V
C-B
) signal.
Additionally, the generator phase C to phase A (V
C-A
) signal is applied to a filtered, zero-cross detector
circuit. This signal is applied to the microprocessor and is used to calculate generator frequency.
B-Phase Line Current
The phase B line current (IB) signal is developed through a customer supplied current transformer (CT)
and monitored through terminals CT1 and CT2. Depending on the option selected, current up to 1 ampere
(style number xx1) or 5 amperes (style number xx5) rms may be monitored at these terminals. The
current monitored at these terminals is scaled and conditioned by an internal current transformer and
active circuitry for use by the ADC. The signal applied to the ADC is used to calculate the rms value of
phase B line current.
Additionally, the phase angle between phase B line current and phase C to phase A generator voltage is
calculated for use during droop and var/power factor operation.
Accessory Input (Auxiliary Adjust)
This input allows adjustment of the DECS-100 regulation setpoint by the application of a positive or
negative dc voltage across terminals A and B. Positive voltage applied to terminal A with respect to
terminal B will cause the active mode setpoint to increase. Voltage from –3 to +3 Vdc may be applied to
this input. The circuit induces a 1,000-ohm burden on the dc source. The Application of a ±3 Vdc signal
corresponds to a ±30 percent change in setpoint.
Field Voltage
Voltage (V
FIELD
) across the regulator field output terminals, F+ and F–, is monitored, scaled, and
conditioned before being applied to the ADC. This signal is used to calculate the dc value of field voltage
for use in system protection.
Field Current
Current (I
FIELD
) through the main power output switch is converted to a proportional voltage level. This
voltage signal is scaled and conditioned before being applied to the input of the ADC. The result is used
to calculate the dc value of field current for use in the Manual mode of operation as well as protection of
the system.
Contact Input Circuits
Five contact input circuits powered from an internal 13 Vdc power supply provide input control from user-
supplied, isolated, dry-type contacts.
Raise
Closing a contact across terminals 6U and 7 causes the active operating setpoint to increase. This
function is active as long as the contact is closed.
Lower
Closing a contact across terminals 6D and 7 causes the active operating setpoint to decrease. This
function is active as long as the contact is closed.
Var/Power Factor Control (52J/K) Option
Closing a contact across terminals 52J and 52K disables var/power factor control. An open contact
enables the DECS-100 to control the generator reactive power in either the var or the power factor mode.
The contact has no effect when this function is not enabled in the software. For more information, see
Parallel Generator Compensation (52L/M) and Voltage Matching Control Option.
Parallel Generator Compensation (52L/M)
Closing a contact across terminals 52L and 52M disables parallel operation. An open contact enables
parallel operation and the DECS-100 operates in reactive droop compensation mode.