NaoDec Vertex Series Coil Rev 1.0a
Interactive schematic of a current-limited sixty-coil series electromagnet loop.
N A O D E C
VERTEX SERIES COIL - REV 1.0A
60-coil pre-release design | dual-pot XL4015 CC/CV | exact 3 A input fuse | thermal cutoff
12V INPUT / CC LOOP+
0V / RETURN
CURRENT-LIMITED POWER AND SERIES LOOP
12 V PSU
DC SUPPLY
0 V
+12 V
F1
3 A T
C1
220-470 µF
≥25 V LOW-ESR
C2
100 nF X7R
≥25 V
XL4015
DUAL-POT CC/CV
CV 11.0 V | CC 3.0 A
IN+
OUT+
IN-
OUT-
TCO1
70-80 °C
GROUP 1
L1-L3
GROUP 2
L4-L6
. . .
GROUPS 3-19
GROUP 20
L58-L60
CC-REGULATED LOOP+ | ~5.55 V LOADED | 3.0 A
COMPLETE 20 AWG WIRING | ~1.30 Ω MEASURED | KEEP UNCOILED
ONE GROUP - 1 OF 20
JST-F
JST-M
7 T
7 T
7 T
Each coil: 1 mm Cu | 12.5 mm ID | 5 cm lead + 7 cm lead | ~0.417 m copper | crystal core (non-magnetic)
Connector: JST SM 2-pin, both pins paralleled | 20 connectors total | 60 coils total
OPERATING POINT
Cold loop estimate
~1.85 Ω
Regulated output
~5.55 V | 3.0 A
Total output power
~16.65 W
Wiring / coils
~11.70 / 4.95 W
Field per coil
~21 AT
FINAL LOOP RESISTANCE MUST BE MEASURED AFTER ASSEMBLY
WARNING - NEVER RUN THE STRING WITHOUT THE VERIFIED CC/CV BUCK
Direct 12 V would attempt ~6.5 A / ~78 W | exact 3 A T-fuse + 70-80 °C TCO required | keep all 20 AWG runs uncoiled
PRE-RELEASE - BENCH QUALIFICATION REQUIRED
1.30 Ω mock wire + ~0.56 Ω / ≥10 W resistor bank | CV 11.0 ±0.3 V | CC 3.0 ±0.1 A | 30 min burn-in
SIGNAL FLOW, WIRING & CALCULATIONS
POWER PATH
12 V PSU -> 3 A T fuse -> XL4015 -> TCO -> 60 coils -> return
The 11.0 V CV setting is an open-load ceiling. The loaded loop operates in CC mode near 5.55 V.
ELECTRICAL SUMMARY
60 coils
~0.55 Ω calculated at 20 °C
20 AWG installation wiring
~1.30 Ω measured | uncoiled
Complete cold loop
~1.85 Ω estimated
At 3.0 A
~5.55 V | 16.65 W
Power split
11.70 W wire | 4.95 W coils
PROTECTION & WIRING
F1
exactly 3 A T-type | not 3-5 A
Expected PSU input
~1.5-1.7 A at 12 V
TCO1
70-80 °C | ≥5 A | bonded at hot spot
J1-J20
JST SM 2-pin | both pins paralleled
XL4015 MOCK QUALIFICATION
Mock load
1.30 Ω wire + ~0.56 Ω / ≥10 W bank
Open-load CV
11.0 ±0.3 V
Full-load CC
3.0 ±0.1 A | steady
Clamp / burn-in
≤3.1 A on 1.30 Ω | 30 minutes
Reject any module with pulsing, drift, smoke, odour, or unstable current regulation.
BILL OF MATERIALS & XL4015 HARNESS
#
QTY
REF
DESCRIPTION
1
1
D1
1N5819 / 1N4007 flyback (optional, only if electronically switched)
2
1
F1
Exactly 3 A slow-blow T-type | buck input
3
20
J1-J20
JST SM 2-pin | both pins paralleled
4
60
L1-L60
7 T | 1 mm Cu | 12.5 mm ID | crystal core | ~0.417 m each
5
1
U1
Dual-pot XL4015 HW-083-B | CV 11.0 V | CC 3.0 A
6
1
W1
Complete 20 AWG installation wiring | ~1.30 Ω measured
7
1
PSU1
12 V DC supply | fused isolated positive branch
8
1
C1
220-470 µF low-ESR electrolytic | ≥25 V | XL4015 input
9
1
C2
100 nF X7R ceramic | ≥25 V | parallel with C1
10
1
TCO1
70-80 °C thermal cutoff | ≥5 A | manned installation
U1 XL4015 HARNESS
PIN
NAME
NET
CH
IN+
VIN+
12V_IN
IN-
VIN-
GND
OUT+
VOUT+
LOOP_POS
OUT-
VOUT-
RETURN
PROTECTION SUMMARY
F1
3 A T-type
TCO1
70-80 °C | ≥5 A
C1
220-470 µF | ≥25 V
C2
100 nF X7R | ≥25 V
CC LIMIT = REGULATION
FUSE + TCO = FAULT PROTECTION
ONLY USE A TRUE DUAL-POT
CC/CV MODULE
ENGINEERING NOTES & REVISION HISTORY
1.
At steady-state DC, inductive reactance tends to zero. The loop behaves
as an approximately 1.85 Ω resistive load pending final assembly measurement.
2.
The crystal core is non-magnetic (µ approximately air), so it provides no
field boost. Each seven-turn coil produces approximately 21 ampere-turns at 3 A.
3.
The XL4015 current-control loop is the operating current limiter. A CV-only
or fixed-output board is not acceptable for this installation.
4.
F1 must be exactly 3 A slow-blow. C1 and C2 mount directly at IN+/IN-.
The 70-80 °C thermal cutoff is mandatory for manned operation.
5.
Keep every 20 AWG run and all slack uncoiled. Keep bare copper apart and
keep this positive branch isolated from the three LED-supply positive rails.
6.
Bench-qualify each XL4015 with the documented 1.86 Ω mock load before
connecting the real loop, then perform supervised commissioning and thermal inspection.
7.
Do not adjust CV to force 11 V across the loaded loop. Normal operation is
3 A CC near 5.55 V for the present estimated cold resistance.
REVISION HISTORY
Rev 1.0a
- Dark Blue-Mint theme variant (HTML_Document_Recreation_Guide palette):
accent #0ff0b3, --bg #080b10, --warn #ff4f86, GND wire #4d7096.
All technical content unchanged from Rev 1.0.
Rev 1.0
- Strict NaoDec style rebuild with 2026-06-18 design data:
20 AWG / ~1.85 Ω loop, exact 3 A T-fuse, dual-pot XL4015,
input decoupling, TCO, current calculations, and mock qualification.
Document rebuild: 2026-06-19. Values remain provisional until final measurement.
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