Master Circuit

This blog cover the master circuit and hardware used.

Overview
To save weight an alternative solenoid was sourced based on a recommendations found on the Matronics site.

Each of the three [3] circuits has a separate bus supplied to a switch/breakers rated to meet the total demand of each circuit they supply.

Installation
To facilitate maintenance and installation it was decided to install a series off AMP plugs  at the circuit breaker panel and the airframe. The plugs were terminated behind the panel on the starboard side into plugs on a dedicated bracket. 

This allows the manufacture of the circuit breaker/switch panel as one assembly on the workbench and then installed into the air-frame.

Note: AMP plugs feature gold plated pins for increased reliability. The 14 guage were a push and required a little more care to achieve a satisfactory connection.

The input from the manual isolator switch was run in 6 gauge wire to the master relay with the panel 15 amp switch/breaker feed with individual 14 gauge wires and the 10 amp switch/breaker supplied with a 16 gauge feeder. 

Each run was terminated onto their respective breakers using the screw connections supplied.

The main feed to the through the breaker was run in 6 gauge aluminum / copper clad cable for increased margin. The cable ends were fitted with nipples behind the panel to prevent accidental shorts when servicing that area.

Note: Battery fuse is 50 amps / Generator 30 amps

Load check wire selection

Schematic - Master-20 

Batteries
Two [2] LifePo4 each with 20 amp hour [lead equivalent] and 230 CCA were installed into the rear compartment to achieve a 18%MAC - it not moving again that is a guarantee. 

The MAC is at 18.5% empty with the relocated pump. The current battery's combined with relocating the hydraulic pump saved me 4kg [8.8 lbs] compared to the current battery. Since the original selection of batteries, EarthX in the USA have release a superior battery and the existing batteries may be replace by these at some point. 

At the positive terminal a 125 amp lo-Blo® fuse was installed to eliminate nuisance blowing during temporary, short duration overloads. These are commonly used for battery and alternator connections and other heavy gauge cables requiring high current protection in automobiles. 

The connection to the positive stud was made using a rigid bus to save space and weight.

The existing cables were then run to the underside of the folded channel and terminated with the same studs used at the firewall as the  aluminium cable used is light but stiff.

From the studs colour coded battery cables were manufactured from flexible battery cable connecting the battery to the aluminium cable allowing ease off battery removal and preventing any chance confusion at reinstallation.

Circuit Fuses
Two holders that accept automotive maxi fuses were installed on the firewall to protect the supply to the breaker panel and the generator rated at 50 / 20 amps respectively. 

The holders were fitted into a folded 0.030'' aluminium channel as it proved impractical to mount with the single bolt mount provided. Both channels were riveted to the firewall and then the holder bolted with a cap hd screw into a M4 rivet nut.

The lug at the rear was designed to engage into a guide on the
original application requiring a custom bracket mount
However they were light/compact when installed

Isolator
It was originally intended to use a manual switch as a isolator without a master solenoid but this has proved impractical. The manual isolator is now a TRUE isolator in the automotive sence - pull cord - ALL power is removed. 

In any track car the crews must have a means to shut the whole car down and that task is performed by these mechanical isolators.

In my aircraft in a rapid emergency where there is no time to clean up all the separate panels created - Pull the red ring. 

Comment
Worked as planned.  

The isolator will require a mechanical pump to work 100% as planned - watch this space - the motor is going to the shop to be upgraded and the final configuration will be decided once were verify a few items on a test stand.


This blog was not intended to give a running description of the day by day work - refer to Facebook Gary Spencer Salt for more frequent general updates.