AMETEK MX CTSH - Manual (Page 27)

California Instruments Revision H 27
User Manual MX Series CTSH Compliance Test System
3.4.3 OMNI-3-75 Hardware Versions
Note that original versions of the OMNI-3-75 (version 1) did not have front panel circuit breakers that enable
disconnection of the OMNI output to the PACS input. Later versions of the OMNI-3-75 (version 2) do have
either one or two front panel breakers. These breakers replace the need to manually connect and
disconnect one of the other OMNI in MXCTSHL systems that contain both an OMNI-3-75 and an OMNI-3-
37MX.
Note: The MXCTSHL systems have both OMNI’s, OMNI-3-75 and OMNI-3-37MX. Only one of the two circuit
breakers should be turned on (connected) at one time. If both are on, the two OMNI’s will be in parallel
and the correct reference impedance will not be present. Thus, always connect (close) only one of the
two circuit breakers on the OMNI-3-75 cabinet at a time.
The circuit breakers provide additional protection against over current for each of the relevant OMNI circuits
and PACS.
3.4.4 Wiring
Power from the MX three-phase output connector should be routed to the OMNI AC Input terminal block
inside the cabinet. To access these connections, the rear panel screen of the OMNI-3-75 needs to be
removed. The recommended wire gauge is #4.
Output power from the OMNI-3-75 must be routed to the PACS-3-75 input connector. (TB4) To access the
PACS-3-75 AC input and output connections, the rear-top cover of the PACS-3-75 must be removed. This
wiring is generally installed at the factory and should already be in place. Wire size used is AWG #6, which
is the maximum size supported by the PACS-3-75 connectors. Note that the wire fits very tightly in theTB4
connector. It may be necessary to twist stranded wires firmly to make the wire fit the connector opening.
The EUT connections can be made at TB3 AC OUT of the PACS-3-75. The wire size should be AGW #6
also. To gain access to power connector TB3, the access panel located on the top rear of the PACS-3-75
unit must be removed. Remove the four screws holding the connector access panel in place and remove
the panel. Once input and output wiring is complete, reattach the connector access panel.
The connection diagram is shown in Figure 3-7. Note that is the PACS-3-75 is installed in the OMNI-3-75
cabinet, the wiring between the OMNI-3-75 output and the PACS-3-75 input is inside the cabinet (in
contrast to what is shown on the drawing). Wiring diagrams for other possible systems configurations are
shown in Figure 3-3 through Figure 3-6. For older systems with out circuit breakers on the OMNI-3-75
cabinet, refer to Version 1 schematics Figure 3-7 through Figure 3-9
Note: This wiring supports EUT load currents up to 75 Arms. For higher power EUT's used with the MX, the
PACS-3-75 should not be left in the circuit. Instead, EUT's that require higher currents should be
connected directly to either the MX output or the OMNI-3-75 AC Output, which are both rated for higher
currents than the PACS-3-75. In this case, harmonics and flicker testing is not supported.