3.1.7Load Transfer Procedures Screen
Go to the SCC Master Menu and move the highlighted cursor to LOAD TRANSFER PROCEDURES. Note that this screen is displayed at the System Control Cabinet but is not required at the UPS modules. Press the Select pad and the Load Transfer Procedures screen is displayed.
The Load Transfer Procedures screen contains instructions to transfer the critical load between the UPS system and the bypass line. Comparisons of the UPS and bypass voltage, frequency, and phase synchronization are dis- played along with transfer status messages and an indication of circuit breaker overlap time. The metered param- eter values on the Load Transfer Procedures screen are updated at
Refer to 3.3.2 - Load Transfer Procedures for more details.
Figure 36 Load Transfer Procedures Screen
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| SELECT : MASTER MENU |
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| SYNCHRONIZATION | |||||||||||
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| VOLTAGE COMPARISON |
| FREQUENCY |
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UPS | - |
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| 0 | +30 | ||||||||||
480 | 480 | 480 |
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| 4 | 60.0 Hz | ||||||||||
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BYPASS | - | 481 | 480 | 479 |
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| 60.0 Hz |
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ON UPS
OK TO TRANSFER
TRANSFER PROHIBIT
3 |
| MANUAL |
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UPS LEAD | = 2 Deg | ||||
| TRANSFER INSTRUCTIONS | ||||
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1.Adjust the UPS voltage until it equals the bypass voltage with the VOLTAGE ADJUST pot.
2.If the OK TO TRANSFER message is highlighted, simultaneously press the BYPASS and CONTROL ENABLE buttons.
3.Verify that the transfer was successful by checking the breaker status on the "MONITOR/MIMIC" screen.
4.Press the ALARM RESET button to clear alarms which
are no longer active
Item 1 - Voltage Comparisons. This chart shows the UPS and bypass voltage and frequency comparisons between each of the three phases. If the UPS and bypass voltages are not within specified tolerances, a manual transfer is not permitted and TRANSFER PROHIBIT is highlighted.
The Voltage Adjust knob
CAUTION
The UPS output voltage responds very slowly to inputs from the Voltage Adjust knob. Make small adjustments and wait several seconds each time for voltage to stabilize before continuing.
Item 2 - Synchronization. This display shows the phase synchronization between the UPS output and bypass power. If the phase displacement is outside of the tolerance, a manual transfer is not permitted and TRANSFER PROHIBIT is highlighted.
During normal operation, the synchronization display should read UPS LEAD from zero to 4 degrees.
Item 3 - Status Messages. Three messages are constantly displayed here. Only the active message is high- lighted. If TRANSFER PROHIBIT is highlighted, manual transfers/retransfers cannot be performed, and auto- matic retransfers will not be initiated.
Item 4 - Manual Transfer Instructions. These instructions assist the operator in transferring the critical load between the UPS system and the bypass line.
If the load is on the bypass line, step 2 on the screen will instruct you to press the UPS and Control Enable but- tons to retransfer the load from the bypass line to the UPS system.
Operation 57
