Pre-Amplifier Low Voltage Power Distribution and Fuses in the NEMA Box -------------------------------------------------------- Original Rev. 16-JAN-2007 Current Rev. 20-FEB-2007 Since the "Bo Ducks" meeting on 12-JAN-2007 MSU has had the responsibility for the Pre-Amplifier Low Voltage power distribution wiring and fuses inside of the NEMA box. The plan to take care of this is the following: - The DC power cord from the Pre-Amplifier Power Supply Chassis consists of 9 wires of #14 AWG. These 9 wires supply the three sections of the Pre-Amplifiers as follows: FET_Vcc Red +8 Volts FET_Return Black FET_Vee White -6 Volts DRV_Vcc Red +8 Volts DRV_Return Black DRV_Vee White -6 Volts FLTR_Vcc Red +5 Volts FLTR_Return Black FLTR_Vee White -5 Volts - On the DC power cord, each of these 3 section will have its own Chinch Jones connector where it plugs into the NEMA box. Chinch 2400 series Jones connectors are an appropriate connector to use for this application but they do not seem to be easy to purchase any more. Each power supply section will use its own 4 contact Jones connector. These we must paint them different colors to keep them straight (even through no damage will be done if they are plugged into the wrong place. The cable connector is a Chinch S-2404-CCT socket connector. Mounted in a cutout in the NEMA box is a Chinch P-2404-AB plug connector. Can we make a recess bracket to mount these 3 Chinch plugs in ? All connectors are wired: Vcc on pin #15 Vee on pin #16 Return is on pins #13 and #14 - Inside the NEMA box there is a separate fuse for each supply to each of the 6 PMB-16 cards. All fuses are Bussmann MDL-2 1/4 Amp mounted in Bussmann S-8002-12 fuse holders. All 6 fuses for a given supply are mounted next to each other. Thus the wiring from the Jones connectors mounted in the NEMA Box walls is straight forward and will be done with #14 AWG wire of the same color as used in the DC power cable. The DC power wiring from the PMB-16 cards to the fuse blocks will involve all of the criss-crossing. This wiring is all #22 AWG. The following color codes will be used. FET_Vcc Red +8 Volts FET_Return Black FET_Vee White -6 Volts DRV_Vcc Orange +8 Volts DRV_Return Black DRV_Vee Gray -6 Volts FLTR_Vcc Yellow +5 Volts FLTR_Return Black FLTR_Vee Blue -5 Volts Note that all of the Return wires are Black so these must be kept separate and connected to the correct Return when the Pre-Amp DC power wiring is installed in the NEMA box. The DC power wiring to each PMB-16 card will run through its own webbing and its own grommet into the Copper Pre-Amp Box. - The return wires from the Pre-Amps will connect via Chinch barrier strips to the return wires that run through the Jones Connectors to the DC power cable to the Pre-Amp power supply. - The bulk of this Pre-Amp DC power wiring can be done outside of the NEMA box and then installed as a unit. All of the fuse blocks and barrier strips can be mounted onto a plate which is installed as a unit. The Jones plugs can be mounted into a 1/2" aluminum plate so that they are recessed from the surface of the NEMA box and mount as a unit. Wire Plane Bias Voltage Distribution and Filters in the NEMA Box ---------------------------------------------------- Original Rev. 16-JAN-2007 Current Rev. 22-JAN-2007 Since the "Bo Ducks" meeting on 12-JAN-2007 MSU has had the responsibility for the connectors on the NEMA box that will receive the Wire Plane Bias Voltage Supplies, the first stage filters on these Bias Voltage supplies and for the distribution of the filtered Bias Voltages to the PMB-16 cards. Even though we anticipate operating Plane B at zero Bias Voltage, there will be Bias Voltage input connectors and first stage filters to provide Bias Voltage to all 3 wire planes. Note that in the initial operation of ICARUS they did not operate the B Plane at zero Bias Voltage. The NEMA box Bias Voltage input connectors are SHV type and are mounted to the NEMA box in a way that provides electrical isolation. The outer shell of the SHV connectors is connected to the NEMA box (and thus to the NEMA box ground) via a 100 Ohm 1 Watt resistor. This 100 Ohm resistor is large enough to break the ground look with the Bias Voltage power supplies and is small enough to ensure that the shields on the the Bias Voltage cables are held at ground potential. The center conductor of the of the SHV connector passes through two 47k Ohm resistors in series and then into the high side of a 1 uFd 1600 Volt polypropylene capacitor. The ground side of this capacitor is tied to the filter ground which is the NEMA box ground. The Bias Voltage is carried from the filters to the PMB-16 cards on twisted triple #22 wires with 16 mil PVC insulation. At the filter end the red wire connects to the filter output through a 100 Ohm 1 Watt resistor and the two black wires connect to the filter ground through a common 100 Ohm 1 Watt resistor. At the PMB-16 end of these cables there is a 1x5 AMP connector housing. The red wire connects to pin #3 and the two black wires connect to pins #1 and #5. There is a separate twisted triple cable for each of the 6 PMB-16 cards. Two of these cables run from each Bias Voltage Filter.