Basler DECS-150 Instruction Manual page 228

27-4
Poor Voltage Regulation
Step 1. Verify that the DECS-150 is properly grounded.
If the DECS-150 is not properly grounded, connect a dedicated ground wire to the terminal
labeled GND on the DECS-150.
If the DECS-150 is properly grounded, proceed to Step 2.
Step 2. Check for grounded field leads.
If the field leads are grounded, isolate them from ground.
If the field leads are not grounded, proceed to Step 3.
Step 3. If the DECS-150 is powered from a PMG, check for grounded PMG leads.
If the PMG leads are grounded, isolate them from ground.
If the PMG leads are not grounded, proceed to Step 4.
Step 4. Verify that the machine frequency is not dropping below the DECS-150 Underfrequency setpoint
when load is applied to the machine.
If the machine frequency is dropping below the Underfrequency setpoint, reduce the setpoint if
possible. Also check the prime mover and machine for proper sizing in relation to the applied
load.
If poor regulation is not related to DECS-150 underfrequency operation, proceed to Step 5.
Step 5. Verify that regulation is not being affected by normal droop operation.
If droop operation is not affecting regulation, proceed to Step 6.
Step 6. Replace the DECS-150 unit.
Machine Output Unstable (Hunting)
Step 1. Verify that the governor for the prime mover is operating properly.
If the governor is not operating properly, troubleshoot using the manufacturer's suggested
procedures.
If the governor is operating properly, proceed to Step 2.
Step 2. Verify that the sensing and input power leads are connected securely.
If the sensing or input power leads are not connected securely, tighten the connections.
If the sensing or input power lead connections are secure, proceed to Step 3.
Step 3. Verify that the DECS-150 AVR gains are set properly.
If the gain settings are incorrect, reset the gains.
Overexcitation Indicator is Annunciating
Step 1. Check for machine overloading.
If the machine is operating with a larger than rated load, shed load.
If the machine is operating with a rated or less than rated load, proceed to Step 2.
Step 2. Verify that the machine exciter field voltage requirements are compatible with the DECS-150.
If the exciter field voltage requirements are not compatible with the DECS-150, contact Basler
Electric Customer Service for recommendations.
If the exciter field voltage requirements are compatible with the DECS-150, proceed to Step 3.
Step 3. Replace the DECS-150.
Troubleshooting
9492600990
DECS-150