GE Digital Energy STS-400-25-3 Installation And Operating Manual page 31

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Digital Energy Static Transfer Switch
4.3.2 Main fuse exchange procedure
1. Open the door of the STS.
2. Bypass the load to either the primary or secondary source according to one of the two procedures
described in chapters 4.2.1 and 4.2.3. After that procedure switches K3 STS OUTPUT, K4 STS
PRIMARY SOURCE and K5 STS SECONDARY SOURCE should be in "OFF" position.
3. Remove the panel marked with label "MAIN AND AUXILARY FUSES".
4. Check the state of the circuit breakers used for fuse burn indication. If neither is switched off,
probably there is no need to exchange fuses at all. If any fuse should be exchanged, its circuit
breaker should be in off position.
5. Remove burnt fuses and close the cover properly.
6. Switch on the circuit breaker(s) used for fuse burn indication.
7. Reinstall the panel marked with label "MAIN AND AUXILARY FUSES".
8. Return from bypass to STS operation according to one of two procedures described in chapters
4.2.2 and 4.2.4. After that procedure switches K3 STS OUTPUT, K4 STS PRIMARY SOURCE
and K5 STS SECONDARY SOURCE should be in "ON" position. Switches K1 STS PRIMARY
BYPASS and K2 STS SECONDARY BYPASS should be in "OFF" position.
9. Close the door of the STS.
4.3.3 TVSS fuse exchange procedure
1. Open the door of the STS.
2. Bypass the load to either the primary or secondary source according to one of the two procedures
described in chapters 4.2.1 and 4.2.3. After that procedure switches K3 STS OUTPUT, K4 STS
PRIMARY SOURCE and K5 STS SECONDARY SOURCE should be in "OFF" position.
3. Remove the panel marked with label "MAIN AND AUXILARY FUSES".
4. Check fuses KO1, KO2 and KO3 (9 fuses in three fuse holders) and the TVSS units with an
ohmmeter. Burnt TVSS may be located with an ohmmeter or just by visual inspection, without any
tools.
5. Exchange the damaged TVSS units as well as their fuses.
6. Reinstall the panel marked with label "MAIN AND AUXILARY FUSES".
7. Return from bypass to STS operation according to one of two procedures described in chapters
4.2.2 and 4.2.4. After that procedure switches K3 STS OUTPUT, K4 STS PRIMARY SOURCE
and K5 STS SECONDARY SOURCE should be in "ON" position. Switches K1 STS PRIMARY
BYPASS and K2 STS SECONDARY BYPASS should be in "OFF" position.
8. Close the door of the STS.
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GE DE STS: installation and operating manual 1.1 (GB)
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