The MBS has 3 positions: UPS, Test and Bypass. When the MBS is turned to
the Test position, the UPS is already turned to maintenance bypass and it no
longer provides protected input to the load, but enables testing of the UPS
internal functionality.
To turn the UPS to maintenance bypass:
1.
Follow the normal start position:
Figure 38. Normal positions of the MBS switches and rectifier disconnect switch
(must be located in the site wiring)
A Static bypass input
1
Maintenance Bypass Switch (MBS)
B Rectifier input
C Out
2.
Perform the transfer from the double conversion mode to the bypass mode
. Remember to verify the transfer before
proceeding to the next step.
3.
Turn the MBS from the UPS position to the Test position.
4.
Perform the LOAD OFF procedure as described in Section
.
5.
Turn the MBS from the Test position to the Bypass position.
6.
Turn off the rectifier switch to disconnect the UPS rectifier input.
7.
Turn off the static bypass switch to disconnect the UPS bypass input.
The UPS is now in the maintenance bypass mode:
Eaton 91PS/93PS UPS 8–40 kW
User's and installation guide
©
Eaton Corporation plc 2018. All rights reserved.
Revision: 005
Document ID: P-164000493
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