Alpha Technologies AMP24 HP - Manual (Page 45)

43 Doc. #: 0260011-J0 Rev B
Figure 23 — Representative system wiring for AMPS24 HP system with MBS
5.5 AMPS24 HP with External Maintenance Bypass Switch
An external MBS switch allows the entire AMPS24HP system to be taken offline for maintenance.
Figure 23 shows the logical interconnections. It is not a detailed representation of the actual system
wiring.
5.5.1 External MBS Installation
Install and test the MBS before beginning installation of the AMPS24 HP system.
1. Install the MBS according to the instructions in the MBS installation manual.
2. Place the bypass switch in both BYPASS and UPS and test the continuity at the dedicated AC
distribution panel (see Figure 23).
5.6 Generator Automatic Transfer Switch
An on-site Automatic Transfer Switch (ATS) for a generator (see Figure 23) must meet either of the
following requirements:
• Uses an open-transition transfer switch that has a minimum open time of one second for a re-
transfer from generator to utility or from utility to generator testing, or
• If the transfer is less than one second, then ATS monitors phase angle and will only initiate a
transfer if the two sources are within +/-30 degrees of synchronization.
AC
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