Powerbus PWM adapter problem

  • Hello Richard,

    I'm using the PWM adapter to power the 2 IBEC's powering the ignitions for my P-38. both IBEC's for the left engine are plugged into one port of the adapter using a multi servo connector block. I've had 2 PWM modules fail and cause the engine to flame out one in flight. the port seem to work when first turned on until I start the engine and after a few seconds the voltage from the port (3) the IBEC's are connected to drops to around 2 volts, I programmed port 4 to the correct channel and moved the IBEC's to that port and It worked fine for one flight now that port has failed in the same manner. the PWM adater is rated to 20 AMP's but how much can each port handle, both ignitions at full throttle should be pulling no more that 2-3 amps combined. Should I just use the signal from the PWM adapter to control the IBEC's and feed them power from a separate source or run them from 2 separate ports on the PWM adapter. Looking to see if there is something that I'm missing before throwing in another PWM module, the one on my right engine is setup the same and has not had a problem so far.


    Thanks Wayne

  • Hello,

    there are fuses inside. What they don´t want is pulsed current drawn. What I don´t understand is why you are using the adapters for a ignition Powersupply? Use a SparkSwitch or a SparkSwitch Pro instead with a seperate ignition battery to seperate ignition and receiver!

  • The purpose of the IBEC (Ignition battery elimination circuit) is to power the ignitions using the receiver batteries and saving the added weight and space of carrying more batteries while keeping any ignition noise from affecting the radio system. My plane is large but very limited on space and having to meet the US weight limit means the weight of the 4 batteries needed for the twin ignitions of each engine (3w150R2's) had to be eliminated. SparkSwitch's are great products but don't meet my need to loose the added battery weight.

  • Hello Wayne,


    I understood why you want to use IBEC, but in some cases, for some engines (Zenoah), I used a solution with SparkSwitch Pro, where I connected IBEC (and in my case +regulator) between SparkSwitch Pro receiver (telemetry) input and SparkSwitch Pro ignition battery port.

    I saved a lot of cables and other circuits :-)

    Of course, maybe it is not an ideal solution, but working for me, without any influences of the receiver battery pack.


    have a great day

    Rudolf