As an early adopter, I'm drawn to technology that offers advancement, but before installing a new piece of technology in my plane, there have to be clear cut advantages together with improved reliability over existing devices - it's a safety issue.
From the perspective of risk assessment, you can rank each device in an aircraft in a hierarchical structure. Failure of some elements are catastrophic, while others are merely undesirable. The integrity of your bus structure tends toward the first category. It's hard to improve on the simplicity of the series circuit connecting your switch, breaker and load. Wiring the Vertical Power VP-X system requires the same wiring tasks as a conventional system with breakers. Switches are connected to the control box then loads are connected to that same box. No savings in installation time or wire there. Breakers are controlled by a processor and susceptible to malfunction due to power supply faults, processor failure and coding errors. In other words, the MTBF will almost certainly be shorter than stand-alone breakers. Quoting MTBF figures for individual components such as ECB's are not useful numbers in isolation. The only meaningful number is the "system MTBF". This takes into account the weaker links in the chain.
The VP-X system offers the ability to monitor current in each circuit though this is of limited value. Currents vary according to the mode of operation of each device, such as between transmit and receive on a radio for instance. Unless we have a record of this data, analyzing each value in flight to determine whether it is outside predefined parameters is impossible. Do you know what current your radio should draw when you press PTT? In the event your EFIS fails, you also lose your monitor and control functions and the option of resetting breakers. Something I'd like to keep within my control.
The one thing that is essential in any wiring design is that when prescribed current limits are reached, power is removed and a traditional set of circuit breakers perform this task admirably at low cost.
Jim
From the perspective of risk assessment, you can rank each device in an aircraft in a hierarchical structure. Failure of some elements are catastrophic, while others are merely undesirable. The integrity of your bus structure tends toward the first category. It's hard to improve on the simplicity of the series circuit connecting your switch, breaker and load. Wiring the Vertical Power VP-X system requires the same wiring tasks as a conventional system with breakers. Switches are connected to the control box then loads are connected to that same box. No savings in installation time or wire there. Breakers are controlled by a processor and susceptible to malfunction due to power supply faults, processor failure and coding errors. In other words, the MTBF will almost certainly be shorter than stand-alone breakers. Quoting MTBF figures for individual components such as ECB's are not useful numbers in isolation. The only meaningful number is the "system MTBF". This takes into account the weaker links in the chain.
The VP-X system offers the ability to monitor current in each circuit though this is of limited value. Currents vary according to the mode of operation of each device, such as between transmit and receive on a radio for instance. Unless we have a record of this data, analyzing each value in flight to determine whether it is outside predefined parameters is impossible. Do you know what current your radio should draw when you press PTT? In the event your EFIS fails, you also lose your monitor and control functions and the option of resetting breakers. Something I'd like to keep within my control.
The one thing that is essential in any wiring design is that when prescribed current limits are reached, power is removed and a traditional set of circuit breakers perform this task admirably at low cost.
Jim
