Post by akkudakku on Apr 6, 2014 13:57:03 GMT -5
First of all hello, my name is Paul and I'm new around these parts ;-)
I don't have any turbines that I own or have built yet and I came to these forums to learn as much as I can about the math that goes into designing a running gas turbine.
But for now I want to share an idea for a simple engine startup controler that uses only analogue electronics (some OP amps for comparators, some transistors and NE555 for a signal generator and usual resistors and capacitors). The driving force for this idea is that the typical uC boards like Arduino cost too much (for me) and can hang at the worst moment.
The idea is this - we use the typical RPM sensor (IR diode and IR transistor) and convert it's signal to a DC voltage. We use this voltage for several things:
1. We can use a analogue voltometer with a custom scale as a RPM gauge
2. We use it to generate a PWM signal for a fuel pump/gas solenoid (as RPMs ramp up the PWM signal goes from 0% to 100%)
3. We use it to generate a PWM signal for the oil pump to have a lowered pressure for start up that ramps up to max pressure as the engine goes to idle
4. We use it to shut down the ignition and 'FADEC' circuit at desired RPM idle (with a relay that latches, turning off the PWM comparators and connecting the pumps/solenoids to 12V, the RPM gauge would still work).
The idle and max flow of fuel would be set by a valve (eg. ball valve) that has 2 set screws limiting the minimum and maximum opening of the valve. The only thing that operator would have to do is spool up the rotor with a starter motor (with a push button if its bendix style) or with airflow.
All these functions can be done by a very simple and cheap circuit that I could draw up if you guys want to.
What do you think?
I don't have any turbines that I own or have built yet and I came to these forums to learn as much as I can about the math that goes into designing a running gas turbine.
But for now I want to share an idea for a simple engine startup controler that uses only analogue electronics (some OP amps for comparators, some transistors and NE555 for a signal generator and usual resistors and capacitors). The driving force for this idea is that the typical uC boards like Arduino cost too much (for me) and can hang at the worst moment.
The idea is this - we use the typical RPM sensor (IR diode and IR transistor) and convert it's signal to a DC voltage. We use this voltage for several things:
1. We can use a analogue voltometer with a custom scale as a RPM gauge
2. We use it to generate a PWM signal for a fuel pump/gas solenoid (as RPMs ramp up the PWM signal goes from 0% to 100%)
3. We use it to generate a PWM signal for the oil pump to have a lowered pressure for start up that ramps up to max pressure as the engine goes to idle
4. We use it to shut down the ignition and 'FADEC' circuit at desired RPM idle (with a relay that latches, turning off the PWM comparators and connecting the pumps/solenoids to 12V, the RPM gauge would still work).
The idle and max flow of fuel would be set by a valve (eg. ball valve) that has 2 set screws limiting the minimum and maximum opening of the valve. The only thing that operator would have to do is spool up the rotor with a starter motor (with a push button if its bendix style) or with airflow.
All these functions can be done by a very simple and cheap circuit that I could draw up if you guys want to.
What do you think?
).