MGE UPS Systems EPS 7000 - Manual (Page 47)

Operation page 2 —19
Users Manual
2.10.4 With Maintenance Bypass
This procedure assumes that the UPS system is operating normally, with the attached load supplied via the UPS
inverter:
1. Stop the inverter by pressing the “inverter off” pushbutton on the UPS front panel for 3 seconds. The audible
alarm will sound; silence the alarm by pressing the audible alarm reset pushbutton on the hidden panel. See
section 1.5 Shared Systems Indicators and Controls.
If the transfer conditions are not satisfied (bypass out of tolerance or another reason), a forced transfer will be
required., in this case refer to section 2.11 Forced Transfers for procedures.
2. Depress transfer initiate switch. Unlock and remove the key from key interlock. Unlock and close the mainte-
nance bypass circuit breaker Q3BP, see Figure 1-7.
3. Open the UPS isolation circuit breaker Q5N and lock open. The SSC is now isolated from the load which is
supplied by the maintenance bypass AC input source.
4. Open the circuit breaker Q4S.
For complete protection, the upstream circuit breaker (Q4S) supplying the UPS should be opened, locked, and
tagged while the UPS is being serviced. The UPS is now isolated for maintenance.
To restart the UPS after maintenance:
1. Close the upstream bypass circuit breaker Q4S. After about 10 seconds, the wrap-around circuit breaker Q2S
will close.
2. Close the system isolation circuit breaker Q5N.
3. Open the system maintenance bypass circuit breaker Q3BP. The SSC is now on line and the load is supplied
via the bypass source.
4. Restart the UPS modules by following the procedures in section 2.9.
2.10.5 Without Maintenance Bypass
This procedure assumes that the UPS is operating normally, with the attached load supplied via the UPS inverter.
1. Isolate all the UPS modules by following the procedure in section 2.10.3 Isolation of Individual UPS Modules.
2. Open the upstream bypass circuit breaker Q4S.
CAUTION: Opening Q4S with the inverter stopped in a UPS without
maintenance bypass will disconnect the attached load.
The whole UPS system is now isolated for maintenance. For complete protection, Q4S or the upstream circuit
breaker supplying Q4S should be locked open and tagged while the UPS system is being serviced.
To restart the UPS system after maintenance:
1. Close the upstream bypass circuit breaker Q4S. After about 10 seconds, the wrap-around circuit breaker Q2S
will close and supply the attached load via the bypass source.
2. Restart the UPS modules by following the procedures in section 2.9.