DS2020PDMAG6 Power Distribution Module

Fig 1: Power Distribution Module AC to DC Converter

Power filters are used to enter the PDM with the customer’s 125 V de and 115/230 V ac power. One or two ac/dc converters that output 125 V dc are connected to the ac power by cables. In order to create a backup power supply, this de voltage is then cabled back into the PDM and diode linked to the primary dc power. The VME racks and terminal boards receive this power distribution. The ac/dc converters can handle either 115 V or 230 V ac. For operation at 115 V or 230 V, the transformer cable must be inserted into either JTX1 or JTX2. The PDM is used to gather diagnostic data, which is then linked to a terminal board installed on a DIN rail. After that, a cable travels through J301 to the VCMI in rack “R”. Fused and cabled out to the relay terminal boards are the ac feeds, J17–20. The interface (I/O) cabinets, protection modules, TRPG, TREG, and TRLY all have 125 V dc feeders that are fused and wired. The PDM is delivered through a control power filter (CPF), which reduces EMI noise, to ensure a noise-free supply to the boards. As seen in the following illustration, the CPF rack may store two or three Corcom 30 A filter modules. Before being fused and cabled to the TBCI boards, power to the contact inputs first travels through TB2, resistors R3 and R4, and TB2. An excitation voltage of 125 V dc is used for contact inputs.