techmannih/nema34-mounted-stepper-controller

engineering/mechanical/cooling-selection.json

{
  "status": "engineering-selection-incomplete-physical-installation-not-approved",
  "powered_tests_performed": false,
  "motor_operation_authorized": false,
  "driver": {
    "part": "Same Sky HSB14-353518",
    "selection": "selected heat-sink and TIM identities for the bounded first-article test; supported contact assembly requires dimensional fitting",
    "envelope_mm": [
      35,
      35,
      18
    ],
    "base_thickness_mm": 1.5,
    "mass_g": 15,
    "drawing": {
      "source_url": "https://www.sameskydevices.com/product/resource/hsb14-353518.pdf",
      "download_sha256": "fcb850942b680dc0a2a6defad5a60f18751f35dda5d9592c1f400a761080ec87"
    },
    "natural_convection_curve_samples": {
      "power_w": [
        3,
        4,
        15
      ],
      "temperature_rise_c": [
        31.3,
        40.1,
        119.7
      ]
    },
    "forced_air_curve_sample": {
      "power_w": 15,
      "airflow_lfm": 200,
      "temperature_rise_c": 44.2
    },
    "rating_limit": "Manufacturer curve test conditions are not the installed assembly. Natural convection at 15 W is insufficient for the project 110 C junction target at 40 C ambient.",
    "placement_study": {
      "xy_center_mm": [
        22,
        -12
      ],
      "xy_envelope_mm": [
        4.5,
        -29.5,
        39.5,
        5.5
      ],
      "status": "plan-view candidate only; contact/pedestal, height, tolerances and supports not qualified"
    },
    "rejected_direct_fit": {
      "part": "ATS-TI1OP-519-C1-R3",
      "envelope_mm": [
        78,
        36,
        35.6
      ],
      "reason": "EVM support/fin envelope conflicts with current surrounding components"
    },
    "open": [
      "Top-contact geometry, package-height tolerance, pedestal/spreading resistance",
      "Supported retention at both IC ends and <45 N package load",
      "Airflow and failure condition at intended motor current",
      "Clearance to capacitor tolerances, WAGO actuation and live copper"
    ],
    "tim_selection": "Arctic Silver Ceramique 2; not structural adhesive",
    "bench_thermal_budget": {
      "ambient_c": 40,
      "conduction_w": 0.23552000000000003,
      "additional_loss_allocation_w": 3,
      "total_allocated_w": 3.23552,
      "sink_theta_allocation_c_per_w": 12.5,
      "package_theta_c_per_w": 0.7,
      "interface_and_contact_allocation_c_per_w": 1.5,
      "calculated_junction_c": 87.562144,
      "basis": "Conservative natural-convection selection screen; loss/contact allocations and installed airflow are to be measured. Not a full-current cooler."
    }
  },
  "brake": {
    "resistor": "Vishay LPS0300H10R0GB",
    "resistance_ohm": 10,
    "tolerance_percent": 2,
    "rating_w_at_case_85c": 300,
    "datasheet": {
      "source_url": "https://www.vishay.com/docs/50052/lps300.pdf",
      "download_sha256": "80577e8e5c6c1d75ddd9b41d9afb208ed046f1d58c45902bf4926c6410dd0dec"
    },
    "tim_selection": "Bluesil Past 340, per resistor manufacturer mounting guidance",
    "mounting_hardware": "Manufacturer-supplied M4 x 25 class 8.8 screws and M4 contact lock washers; confirm received accessory set",
    "terminal_hardware": "Manufacturer M4 terminal screws, TE152883 rings; verify engagement with actual tongue/washer stack",
    "torque_nm": 2,
    "maximum_torque_nm": 2.5,
    "heatsink_candidate": "Fischer Elektronik SK 100 100 SA, subject to exact drawing/thermal-curve and installed guard review",
    "sink_source": "https://www.farnell.com/datasheets/2576985.pdf",
    "existing_cad_status": "80 x 80 x 30 mm concept retained and explicitly not represented as a rated/selected heatsink",
    "thermal_requirements_at_40c_ambient": [
      {
        "average_power_w": 25,
        "maximum_case_interface_to_air_c_per_w": 1.8
      },
      {
        "average_power_w": 100,
        "maximum_case_interface_to_air_c_per_w": 0.45
      },
      {
        "average_power_w": 300,
        "maximum_case_interface_to_air_c_per_w": 0.15
      }
    ],
    "open": [
      "Load, stop/repetition energy and qualified duty",
      "Heatsink machining/engagement and thermal resistance at installed orientation",
      "Ventilated touch/terminal guard and supported strain relief",
      "Transient element temperature and stuck-on fault containment"
    ],
    "selection": "10 ohm LPS300 retained as the concrete first-article component for the bounded profile; full-duty envelope is not assigned",
    "bench_cooling_selection": {
      "part": "Fischer Elektronik SK 100 100 SA",
      "manufacturer_drawing": "https://www.farnell.com/datasheets/2576985.pdf",
      "maximum_average_power_design_w": 10,
      "ambient_design_c": 40,
      "sink_theta_allocation_c_per_w": 3,
      "interface_allocation_c_per_w": 0.2,
      "calculated_case_c": 72,
      "scope": "Limited bench selection only; installation orientation/guard/interface must satisfy the allocations. Not a 300 W continuous assembly."
    },
    "guard_specification": {
      "material": "1 mm stainless steel perforated enclosure on independent fixture",
      "maximum_opening_mm": 2,
      "minimum_clearance_to_live_terminals_mm": 10,
      "minimum_gap_to_hot_body_and_fins_mm": 15,
      "fasteners": "four captive M4 fixings accessible only with a tool, outside resistor thermal contact area",
      "wire_entry": "insulating gland matched to actual cable outside diameter; separate clamp/strain relief; no sharp metal edges",
      "scope": "Fabrication requirements; final enclosure dimensions follow actual cooler and terminal stack. No ingress/touch-standard certification claimed."
    }
  },
  "reason_not_closed": "The bench parts, thermal allocations and installation requirements are specified. Rear motor thread/depth, supported DDV contact/pedestal geometry and final guard/fastener dimensional fit are not contained in the available motor STEP. Those dimensions are physical installation inputs, not software faults.",
  "commissioning_scope": {
    "profile": "bench-test",
    "maximum_current_request_rms_a": 0.8,
    "nominal_quantized_rms_a": 0.7734,
    "maximum_rpm": 10,
    "maximum_run_seconds": 10,
    "load": "ordered motor rotor only, no attached load/backdrive",
    "source": "docs/commissioning.md",
    "selection_is_not_installed_fit_evidence": true
  }
}