This guide explains how to prepare the wiring and assemble connectors for the Terminal Connector Kit for the PXIe-4150/4151 power supplies and PXIe-4051 electronic load.

For Weidmuller product wiring instructions including compatible conductor sizes, wiring stripping lengths, and ferrule guidelines, refer to Weidmuller Assembly instructions PUSH IN connector—BVF 7.62HP Hybrid.

NI Accessories

Backshell

Manufacturer: NI

Manufacturer Part Number: Included in the Terminal Connector Kit for PXIe-4150/4151 power supplies and PXIe-4051 electronic load (not orderable individually).

Recommended Multi-Conductor Cables

The following off-the-shelf multi-conductor cables are recommended for use with these products, because the cables minimize lead drop by maximizing conductor diameter within the constraints of the backshell and provide an overall shield to minimize susceptibility to electromagnetic interference.

The most readily available multi-conductor cables have uniform conductor sizes within the cables. Therefore, all the following recommendations assume that you are using both sets of HI and LO force pins. The recommendations also assume that each force pin has multiple conductors crimped into a shared ferrule. Use this approach to achieve low effective resistance for the force leads without exceeding the maximum AWG for the sense terminals or devoting excessive copper area to the sense leads.

Resistance for 18 AWG flexible conductors varies slightly based on stranding and conductor twisting. Typically, resistance is under 23.3 mΩ/m at room temperature. As a result, paralleling 18 AWG conductors results in effective force lead resistances of:

• 4 conductors in parallel: < 6 mΩ/m @ 23 ℃ (150 mV drop/lead @ 25 A, 240 mV drop/lead @ 40 A)
• 5 conductors in parallel: < 4.8 mΩ/m @ 23 ℃ (120 mV drop/lead @ 25 A, 192 mV drop/lead @ 40 A)

Resistance for the 16 AWG flexible conductors is typically under 14 mΩ/m at room temperature. As a result, paralleling 18 AWG conductors results in effective force lead resistances of:

• 4 conductors in parallel: < 3.5 mΩ/m @ 23 ℃ (87.5 mV drop/lead @ 25 A, 140 mV drop/lead @ 40 A)

Multi-Conductor Cable Preparation and Protective Backshell Assembly

The terminal connector kit for the PXIe-4150/4151 power supplies and PXIe-4051 electronic load includes a protective backshell. The backshell ensures touch safety against hazardous voltages, strain relief, and retention. This section provides example guidance for preparing and terminating a multi-conductor cable using the backshell. This example uses the Belden 28329AS multi-conductor cable; strip lengths and ferrule choices are based on that cable.

1. Cut back the multi-conductor cable's outer jacket and shields 40 mm to 45 mm. Longer lengths generally result in exposed individual wires being visible outside the backshell. Generally, shorter lengths do not provide enough room to fan-out to the various connector terminals.

   

2. Separate the drain wire for the outer shield and two individual wires for the HI Sense and LO Sense connections. Use the remaining conductors for the HI and LO force connections. Remove at least 12 mm of insulation from the conductors. (Follow wire stripping guidance based on the Weidmuller documentation for your selected wire size and ferrules.)

   

3. Remove 8 mm of insulation from the remaining two conductors for HI Sense and LO Sense. (Follow wire stripping guidance based on Weidmuller documentation for your selected wire size and ferrules.)

   

4. Depending on the size and number of conductors in the multi-conductor cable, you can separate the force conductors into two or four groups. Then you can crimp the force conductors into appropriately sized ferrules. Using four groups allows the lowest overall resistance in the force path, because it uses both sets of HI and LO pins on the connector. It is helpful to shorten the LO groups by ~ 5 mm to improve fit in the backshell when the groups are fanned out to the individual terminals. You can use ferrules on the drain wire and the sense leads. However, if the lead size is the maximum for these terminals (18 AWG), it is best to omit ferrules to avoid fit issues.

   

5. Insert the HI and LO force groups into their respective connector terminals. For the 1-2 LO groups, use the shortened force groups. These groups route to the middle of the connector next to the small signal portion of the connector. This connector is a shorter distance from the fan out point than the other connections. The following images show all wires at the same length to illustrate how the LO groups can bunch up if not shortened. If the groups bunch up, it is more difficult to attach the strain relief to the outer jacket.

   

6. Insert the HI Sense, LO Sense, and Shield GND wires into their respective connector terminals.

   

7. Insert the terminated connector into the lower portion of the backshell as shown.

   

8. Insert the zip tie into the lower portion of the backshell as shown.

   

9. Close the zip tie around the outer jacket of the cable and tighten. Cut away any excess length.

   

10. Attach the upper portion of the backshell by hooking the front edge under the lower half lip and securing the captive screw.