Power_Bars_and_Power_Cables ---------------------------------------------- Original Rev. 20-APR-1995 Latest Rev. 20-JAN-1998 Power Cables Between a Card File and Its Power Supply Chassis ------------------------------------------------------------- On the Backplanes the power cables are connected in the following ways: +5 Volts: Connects to P1 via 6 Ten-Point connectors (6-32 screws) Connects to P2P3 via 11 Ten-Point connectors (6-32 screws) +3.3 Volts: Connects to P2P3 via 2 Power Bars with 8x 10-32 studs per Power Bar -2 Volts: Connects to P1 via 1 Ten-Point connectors (6-32 screws) Connects to P2P3 via 6 Ten-Point connectors (6-32 screws) -4.5 Volts: Connects to P1 via 1 Ten-Point connectors (6-32 screws) Connects to P2P3 via 4 Ten-Point connectors (6-32 screws) -12 Volts: Connects to P1 via 1 Ten-Point connectors (6-32 screws) +12 Volts: Connects to P1 via 1 Ten-Point connectors (6-32 screws) Return: Connects to P1 via 10 Ten-Point connectors (6-32 screws) Connects to P2P3 via 2 Power Bars with 8x 10-32 studs per Power Bar 8 of the Ten-Point connectors on P1 line up with the 8 10-32 studs on the upper GND Power Bar on P2P3. It is not clear how the power cables will connect to the Power Supplies but it may be something like: On the 240 Amp modules (i.e. the +5 Volt and the +3.3 Volt) the connections are made with 5/16-18 hex head cap screws. There are two of these bolts on each of the output terminals. On the 60 Amp modules (i.e. the -2 Volt and the -4.5 Volt) the connections are made with 10-32 hex head bolts. There is one bolt per output terminal. Pos 16x #14 +<==================== +<==================== Eight Ten-Point Connectors +------------------+ +<==================== via a 6-32 screw each. | Power Supply |---+<==================== | | Pos | |-- +<==================== | | +<==================== Eight Ten-Point Connectors | 5 Volt | +<==================== via a 6-32 screw each. | 240 Amp | +<==================== | | | | | | +--------------------- | with 2x 5/16-18 |---+--------------------- Connections to a GND | bolts per output | Neg Power Bar via a 10-32 screw. | terminal |---+--------------------- +------------------+ +--------------------- Neg 4x #6 AGW Pos 4x #6 AGW +------------------+ +--------------------- | Power Supply |---+--------------------- Connections to a +3.3 Volt | | Neg Power Bar via a 10-32 screw. | |---+--------------------- | 3.3 Volt | +--------------------- | 240 Amp | | | | | +--------------------- | with 2x 5/16-18 |---+--------------------- Connections to a GND | bolts per output | Neg Power Bar via a 10-32 screw. | terminal |---+--------------------- +------------------+ +--------------------- Neg 4x #6 AGW Pos 4x #6 AGW +------------------+ +--------------------- | Power Supply |---+--------------------- Connections to a +3.3 Volt | | Neg Power Bar via a 10-32 screw. | |---+--------------------- | 3.3 Volt | +--------------------- | 240 Amp | | | | | +--------------------- | with 2x 5/16-18 |---+--------------------- Connections to a GND | bolts per output | Neg Power Bar via a 10-32 screw. | terminal |---+--------------------- +------------------+ +--------------------- Neg 4x #6 AGW +------------------+ | Power Supply | Pos #6 AGW Connection to a GND | |------------------------- Power Bar via a 10-32 screw. | 2 Volt | | 60 Amp | | | | with 10-32 |---+--------------------- \ | output terminals | +--------------------- | Seven #14 AGW wires +------------------+ +--------------------- | connecting to seven +--------------------- | Ten-Point power taps +--------------------- | via a 6-32 screw each. +--------------------- | +--------------------- / Neg 7x #14 AGW +------------------+ | Power Supply | Pos #6 AGW Connection to a GND | |------------------------- Power Bar via a 10-32 screw. | 4.5 Volt | | 60 Amp | | | | with 10-32 |---+--------------------- \ Five #14 AGW wires | output terminals | +--------------------- | connecting to five +------------------+ +--------------------- | Ten-Point power taps +--------------------- | via a 6-32 screw each. +--------------------- / Neg 5x #14 AGW Total Number of Connections to the Ground Power Bars: +--------------------- |--------------------- Connections to a GND |from +5V Supply Power Bar via a 10-32 screw. |--------------------- Neg 4x #6 AGW +--------------------- +--------------------- |--------------------- Connections to a GND |from +3V Supply Power Bar via a 10-32 screw. |--------------------- Neg 4x #6 AGW +--------------------- +--------------------- |--------------------- Connections to a GND |from +3V Supply Power Bar via a 10-32 screw. |--------------------- Neg 4x #6 AGW +--------------------- from -2V Supply Connection to a GND --------------------- Power Bar via a 10-32 screw. Pos 1x #6 AGW from -4.5V Supply Connection to a GND --------------------- Power Bar via a 10-32 screw. Pos 1x #6 AGW Thus there are a total of 14 cables that connect to the GND Power Bars. All of these are #6 AWG. This is 7 cables per Power Bar. ---> Let's design the Power Bars so that they have 8 locations for connections via 10-32 bolts. How will the 10x GND Ten-Points from the P1 backplane be connected to the P2P3 Ground system ? Via 8 short jumpers with a #6 lug at one end and a #10 lug at the other end. Poorly at RF ! How much #6 AWG wire will be needed ?? Let's estimate the runs from the middle card file to its power supply chassis. So, from the bottom of the middle power supply chassis to the top of the middle card file is 32U or 56". Let's add at each end 1ft to move forward in the rack and 1ft to move to the center of the rack. This gives a run length of 104" or about 8.5ft. Now how many #6 AWG conductors are there per card file?? +5V has 5, +3.3V has 16, -2V has 1, and -4.5V has 1. This is a total of 23. Thus it requires about 195.5 ft (let's call it 200 ft) of #6 AWG per card file. Resistance between Power Supply and Backplane --------------------------------------------- Based on the above described DC power cable layout and on 8 foot long DC power cables what is the total resistance between each supply and the Backplane. Resistance Total Resistance Supply Cable Configuration In This Cable Supply to Backplane -------- --------------------- --------------- --------------------- +5 SUP 16x #14 1.285 +5 RTN 4x #6 0.806 2.091 mill Ohm +3.3 SUP (4x #6) x 2 0.806 / 2 +3.3 RTN (4x #6) x 2 0.806 / 2 0.806 mill Ohm -2 RTN 1x #6 3.224 -2 SUP 7x #14 2.937 6.161 mill Ohm -4.5 RTN 1x #6 3.224 -4.5 SUP 5x #14 4.112 7.336 mill Ohm This is all based on #6 wire having 0.403 mill Ohm per foot and #14 wire having 2.57 mill Ohm per foot; all of which is temperature dependent. Colour Code of the DC Power Cables ---------------------------------- Color Function ------- -------------- Red +5.0 Volt #14 gauge cables Red +3.3 Volt #6 gauge cables Yellow -2.0 Volt #14 gauge calbes Orange -4.5 Volt #14 gauge cables Black all common power return connections #6 gauge cables Crimp Terminals Wire Gauge vs Stud Size vs Number of Wires ------------------------------------------------------------- We need to be able to terminate the following combinations of wires and stud sizes: Wire Number Terminal Used for Gauge of Wires Stud Size this Application ----- -------- --------- ------------------- #14 1 6-32 PV14-6R-M #14 3 10-32 PV8-10R-Q #14 4 10-32 PV8-10R-Q #14 2 5/16-18 PV10-56R-L #14 4 5/16-18 PV8-56R-Q #6 1 10-32 PV6-10R-E #6 1 5/16-18 PV6-56R-E #6 2 5/16-18 PV2-56R-X List of Terminal Types USED Stock as of 25-AUG-1995 ------------------------====- --=====---------------------- PV14-6R-M PV14-6R 1000 PV10-10R 500 PV10-56R-L PV10-56R 100 PV8-10R-Q PV8-10R 100 PV8-56R-Q PV8-56R 100 PV6-10R-E PV6-10R 300 PV6-56R-E PV6-56R 100 PV4-56R 20 PV2-56R-X PV2-56R 20 zxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxzxz 20-JAN-1998 Panduit Terminals Actually Used to Assembly Crates and Power Pans ----------------------------------------------------------------- Total Total per 15 List of Terminal Crate Crate Stock as of Types USED Application + Pan + Pan 25-AUG-1995 ------------------- -------------------- ----- ----- ----------- Blue PV14-6R 1x #14 onto #6 Std 47 705 1000 Yellow PV10-10R 1x #14 onto #10 Std 7 105 500 Yellow PV8-56R 1x #14 onto 5/16 Std 1 15 100 Blue PV6-10R 1x #6 onto #10 Std 10 180 300 5x #14 onto #10 Std 2 Yellow PV4-56R 8x #14 onto 5/16 Std 2 30 20 Red PV2-56R 2x #6 onto 5/16 Std 5 75 20 ------------------------------------------------------------------------ March 1997 Power Bars ------------------------- 25-MAR-1997 Please make 16 of the "Power Bars" that are described in the attached sheets. These are made from 3/8" x 3/8" copper bar stock. This new "March 1997 Power Bar" is very similar to some power bars that you made for us in April or May of 1995. The only difference is that this new power bar design, has the array of Lug Mounting Holes slid over by 0.800" so that the array of Lugs is not in the center of the bar. You may still have a machine setup that would be mostly appropriate for making these new bars. The overall length of the power bars in not critical. It could vary by 50 mils and make no difference to us. The only important thing is that the "board mounting holes" be spaced pretty close to 0.800" apart. I would like to get these bars bright tin plated after you have made them. I will ask Mary to get a PO to have this plating done at Adams Plating in town. I have included an example of the 1995 power bar to help picture what these look like. I want to thank you folks for making these things for us. These are not something that we can purchase commercially in small quantity. Having these bars allows us to do the high current power distribution on our D-Zero backplanes which is essential in making this equipment work properly. I hope that all this drilling in copper is not too obnoxious. Thanks, Dan