Electrical circuit breaker planning 6

18 hours ago

| Working on: Electrical

I have changed course to designing the panel fully myself, and utilising outside help to do the machining, coating (either anodising or powder coating), and text creation (laser etching, with or without paint infil)

I am using the tool ABViewer16 for all the design work

This is an update of

https://webuildplanes.com/adam-dickson-sling2/p/7103/electrical-circuit-breaker-planning-5

and represents a return to the philosophy of

https://webuildplanes.com/adam-dickson-sling2/p/7098/electrical-circuit-breaker-planning-4

I have dumped all W31 switch breakers, making use of MS35038/9 MilSpec switches and KIixon 2TC2 circuit breakers

The standby bus breaker rating are based on

https://webuildplanes.com/adam-dickson-sling2/p/7174/review-of-standby-bus-breaker-ratings

The master and alternator bus breakers (assuming panel power feed) is based on

https://webuildplanes.com/adam-dickson-sling2/p/7175/review-of-master-and-alternator-bus-breakers

This design has 10 switches in a row, 1 switch for the flap, and 2 switches for the master and boost pump, and 22 circuit breakers

The breaker size is matched to the smallest AWG-dependent current limit of any one branch off a given breaker or split downstream of a breaker. Current limits are taken from Table 11-3 on page 11-15 in AC43-13-1B:

22AWG - 5A
20AWG - 7.5A
18AWG -10A
16AWG - 15A
14AWG - 20A
12AWG - 30A
10AWG - 40A
8AWG - 50A
6AWG - 80A
4AWG - 100A

Breaker sizes inferred from the above table are overridden lower by any stated by Dynon, or by current limits of any interconnects

Need to update from this point on:

Flap group

Switches (1):

AN3027-7 (MS35059-27) DPDT (only SPDT needed, but the DPDT much cheaper) mom. on-off-mom on

Left hand group

Switches (2):

"MASTER BAT/+ALT" switch (MS25201-4 / Eaton 8860K4 progressive type) and dimmer with separate breaker

"BOOST" switch (AN3021-2 / MS35058-22 SPST on-none-off)

Right hand group

Switches (10):

"STBY/MAIN" switch (AN3021-3 / MS35058-23 SPDT on-none-on) which can select between the main bus and backup battery output

"EFIS" switch (AN3021-2 / MS35058-22 SPST on-none-off)

"AVNCS" switch (AN3021-2 / MS35058-22 SPST on-none-off)

The following are all on the "avionics" bus

radio
transponder
flarm
backup EFIS
flaps
trim

"AP" switch (AN3021-2 / MS35058-22 SPST on-none-off)

"STROBE BCN/+WG" switch (MS25201-4 / Eaton 8860K4 progressive type) with positions for tail strobe only, and wing and tail strobe together and separate breaker

"NAV LT" switch (AN3021-2 / MS35058-22 SPST on-none-off)

"LAND LT ST/WW" switch use FLyLeds WigWag progressive switch and electronics

"TAXI LT" switch (AN3021-2 / MS35058-22 SPST on-none-off)

"CABIN LT RED/WHT" switch (MS25201-4 / Eaton 8860K4 progressive type) and dimmer with separate breaker

"CAM" switch (AN3021-2 / MS35058-22 SPST on-none-off)

Breakers (22):

"MASTER BUS" => Klixon 3TC7-30

"START" => Klixon 2TC2-5 18AWG cable 10A wire limit, 3A measured so 5A breaker is appropriate

"BOOST" => Klixon 2TC2-3 recommended by Facet

"STBY CHG" - IBBS charge breaker (20 AWG wire limit 7.5A) but overridden to 5A by the IBBS manual - Klixon 2TC2-5

"STBY OUT" - IBBS backup output breaker 10A (limited so as to not exceed the 10A blade fuse and DB15 pin limits) - Klixon 2TC2-10

Total measured current consumption of Simplepack strobe/nav lights

Nav - at 12V 0.25(L)+0.25(R)+0.18(tail) = 0.68A, 1A breaker is recommended

Strobe - manual states 5A breaker recommended, peak current draw exceeds this but low duty cycle

Simplepack wires are 22AWG, even though most of the feeder lines are 18AWG, so 5A max breaker is appropriate

"STROBE" breaker 18 AWG wires, 7.5A size 20 pins shared for the strobe and nav lights, but 5A 22AWG wire limit at light => Klixon 2TC2-5

"NAV LT" breaker 18AWG 10A feed wire limit, 7.5A pin limit, 5A 22AWG wire limit at light => Klixon 2TC2-5

Taxi lights - at 12V 1.66(L)+1.66(R) = 3.33A

"TAXI LT" breaker 16AWG 15A wire limit, 13A pin limit => Klixon 2TC2-10

Landing lights - at 12V 1.66(L)+1.66(R) = 3.33A

The total current drawn is 6.66A, in practice limited to 3.33A since he taxi and landing lights should not be run simultaneously. I will allow for the possibility that a halogen light might be used as a replacement. Only a single bulb should be used across the taxi or landing light roles, i,e given a 6.66A power budget this allows for a single 80W PAR36 halogen light. Since I want the taxi and landing to be on separate CBs and given a possible load of 6.66A on either of these, it is appropriate to have 10A breakers on each. If the taxi and landing circuits are put on a single breaker, then a 10A breaker would be appropriate.

"LDG LT" breaker for the landing and taxi lights (16AWG 13A pin limit, 15A wire limit) => Klixon 2TC2-10

"AP" => 20AWG wires going most of the way though 7.5A size 20 pins in the midsection interconnect but passing through DB15 pins into 22AWG wire, so 5A limit. Maximum combined current of the two autopilots is 4.06A so ok => Klixon 2TC2-5

"USB" 20AWG 7.5A wire limit, 7.5A pin limit Klixon 2TC2-7.5

"EFIS" => Klixon 2TC2-5

"AVNCS" => Klixon 2TC2-10

"COM" - 20AWG 7.5A overridden by Dynon schematic 5A => Klixon 2TC2-5

Com Radio control panel
Com Radio

"XPNDR" breaker 22AWG 5A overridden by Dynon schematic 3A => Klixon 2TC2-3

Transponder
ADS-B receiver

"FLAPS" breaker 20AWG (7.5A wire limit) but actuator current is smaller => Klixon 2TC2-5

"TRIM" breaker 22AWG - 5A wire limit but current draw small => Klixon 2TC2-2 (because a 1A popped)

"BK EFIS" breaker 22AWG 5A overridden by Horis manual 1A => Klixon 2TC2-1

Kanardia Horis

"FLARM" breaker 22AWG 5A overridden by Flarm manual 3A => Klixon 2TC2-3

Flarm fusion
Flarm trafficView80

"CAB LT" breaker 22AWG 5A wire limit, 7.5A pin limit but current draw tiny => Klixon 2TC2-1

"HEADSET" breaker 20AWG 5A wire limit but current draw tiny => Klixon 2TC2-1

Summary

Switches

1 x AN3027-7 (MS35059-27) DPDT (only SPDT needed, but the DPDT much cheaper) mom. on-off-mom on - for flap control

3 x MS25201-4 (Eaton 8860K4) progressive switches

1 x AN3021-3 / MS35058-23 SPDT on-none-on for main/standby need 1

7 x AN3021-2 / MS35058-22 SPST on-none-off) ** need 5

1 x FlyLeds wigwag switch and controller

Breakers

3 x Klixon 2TC2-1A ok ***

1 x Klixon 2TC2-2A ok *

3 x Klixon 2TC2-3A ok ** need 1 more

8 x Klixon 2TC2-5A ok *** need 5 more

1 x Klixon 2TC2-7.5A ok *

4 x Klixon 2TC2-10A ok ** need 2 more

1 x Klixon 3TC7-30 need 1