Hello all,
When controlling a DC motor's speed with PWM and a MOSFET with a PIC ( FET I believe stands for Fire Emitting Transistor!!!! lol ) - the DC motor draws approx 10 Amps - what would happen if the Mosfet goes open circuit? ( and I beleive this happens with FET's )
As I understand the working of the FET, the motor would go max rpm. ( or would it keep it's current setting or would it shut down? )
If this control with the PIC and MOSFET is very critical ie pumping fuel into a turbine engine, if the motor ( pump ) goes max rpm, the turbine rpm would go out of control. The rpm of the turbine is monitored by the ECU electronics and when rpm gets too high, the ECU would decrease pump rpm to get the rpm within set limits. When MOSFET goes open circuit, will I still have the normal PWM control over the pump? This is quite a serious safety issue!
My questions are the following:
1. Is there an alternative way to control the DC motor without using MOSFETs ( but still applying PWM )
2. Is there a possible way that the PIC can monitor the MOSFET and cause the system to shut down in the event of a MOSFET going open circuit? ie cutting supply voltage to the pump.
3. Can a PIC monitor itself or another PIC and in the event of a PIC dying or resetting, shut the whole system down?
All these issues are relevant to my gas turbine engine control project. With a turbine out of control in a radio controlled model aircraft it could be potentially VERY dangerous.
Thank you in advance.
Barry.
When controlling a DC motor's speed with PWM and a MOSFET with a PIC ( FET I believe stands for Fire Emitting Transistor!!!! lol ) - the DC motor draws approx 10 Amps - what would happen if the Mosfet goes open circuit? ( and I beleive this happens with FET's )
As I understand the working of the FET, the motor would go max rpm. ( or would it keep it's current setting or would it shut down? )
If this control with the PIC and MOSFET is very critical ie pumping fuel into a turbine engine, if the motor ( pump ) goes max rpm, the turbine rpm would go out of control. The rpm of the turbine is monitored by the ECU electronics and when rpm gets too high, the ECU would decrease pump rpm to get the rpm within set limits. When MOSFET goes open circuit, will I still have the normal PWM control over the pump? This is quite a serious safety issue!
My questions are the following:
1. Is there an alternative way to control the DC motor without using MOSFETs ( but still applying PWM )
2. Is there a possible way that the PIC can monitor the MOSFET and cause the system to shut down in the event of a MOSFET going open circuit? ie cutting supply voltage to the pump.
3. Can a PIC monitor itself or another PIC and in the event of a PIC dying or resetting, shut the whole system down?
All these issues are relevant to my gas turbine engine control project. With a turbine out of control in a radio controlled model aircraft it could be potentially VERY dangerous.
Thank you in advance.
Barry.