Yesterday I bought a used CPAP machine. It works, but I'm not looking for a CPAP. I have a newer unit which I hardly use.
OK, the hack! It has an air pump in it. Turbo type with a three wire motor. The motor has three wires colored Black, Red and Yellow. The PCB it plugs into has some kind of (probably) MOSFET (or something similar) that runs the motor. Based on computed information received from three air pressure sensors it will run the motor at a programmed RPM. There is no discernible markings on the motor so I just did some experiments. Knowing the power supply delivers 12 VDC I took an old sulfated 12V SLA battery and did some poke testing. When I apply a voltage on various pins the motor snaps to given positions. Since I don't know what the manufacturer called the 12 oClock position I just picked one and went from there. Here's the results:
After testing I organized the positions into the above chart. The silk screen calls them Q16 through Q21 and each is marked 7N0607. There is a seventh; Q23 (same number) which is nearby but doesn't appear to be directly connected to the motor plug through L5, L6 and L7 (obviously a choke of some unknown value).
The desired result (what I'm after) is to power the motor directly using my own home brew motor switching circuit, but this is a good bit above my skill level. I can build but coming up with the design for this - - - I haven't a clue to start where. Obviously those transistors (I'm assuming due to Q labeling) are computer controlled which bases its output off of parameters and sensed airflow and pressure changes. Don't want to hack the board, at present I assume it could be put back together. It won't run continuous without some sort of reprogramming. I've been through all the settings and can't find anything that would allow me to just use it as a simple air pump.
Why you ask? I'm building a large pond and want to infuse air into the water column in some way or another as yet to be determined. Aquarium pumps are just too noisy and don't pump near enough air, so I'd like to use this small 12VDC Stepper Motor (I'm guessing it's a stepper) because it uses low power and amazingly can produce quite a bit of a push of air.
A chip of which I don't know powering similar rated transistors along with a variable sweep through the positions is what I think I want. I said I THINK I want. Obviously I'm open to alternative suggestions. And no, changing the motor but keeping the turbo pump is not an option. It's quite specialized. And for a buck - not a bad price to get something that can be repurposed.
Speaking of ponds, I'll be out back cleaning the 105 gallon pond I currently have. Later this year I'm planning on a 1000 gallon pond (approximately). As for filtration, I have that sorted out. Sort of anyway. The water pump is going to be 120VAC from either a dishwasher or a washing machine drain pump. Waterfalls and jets to circulate the water around the pond. And the air bubbler in the middle.
For those extra curious I'm planning a side basin that is filled from the waterfall but not a part of the pond. In that is going to be an ultrasonic mist unit and its mist is going to flow down a different path into the pond. It may be a year before I get that far. Assuming I'm even able to get the pond built in the first place. Back issues. Son-in-law will help, but I still want to be thoroughly involved in the project. Lots of concrete work along with sealing of the pond against leaks.
OK, the hack! It has an air pump in it. Turbo type with a three wire motor. The motor has three wires colored Black, Red and Yellow. The PCB it plugs into has some kind of (probably) MOSFET (or something similar) that runs the motor. Based on computed information received from three air pressure sensors it will run the motor at a programmed RPM. There is no discernible markings on the motor so I just did some experiments. Knowing the power supply delivers 12 VDC I took an old sulfated 12V SLA battery and did some poke testing. When I apply a voltage on various pins the motor snaps to given positions. Since I don't know what the manufacturer called the 12 oClock position I just picked one and went from there. Here's the results:
After testing I organized the positions into the above chart. The silk screen calls them Q16 through Q21 and each is marked 7N0607. There is a seventh; Q23 (same number) which is nearby but doesn't appear to be directly connected to the motor plug through L5, L6 and L7 (obviously a choke of some unknown value).
The desired result (what I'm after) is to power the motor directly using my own home brew motor switching circuit, but this is a good bit above my skill level. I can build but coming up with the design for this - - - I haven't a clue to start where. Obviously those transistors (I'm assuming due to Q labeling) are computer controlled which bases its output off of parameters and sensed airflow and pressure changes. Don't want to hack the board, at present I assume it could be put back together. It won't run continuous without some sort of reprogramming. I've been through all the settings and can't find anything that would allow me to just use it as a simple air pump.
Why you ask? I'm building a large pond and want to infuse air into the water column in some way or another as yet to be determined. Aquarium pumps are just too noisy and don't pump near enough air, so I'd like to use this small 12VDC Stepper Motor (I'm guessing it's a stepper) because it uses low power and amazingly can produce quite a bit of a push of air.
A chip of which I don't know powering similar rated transistors along with a variable sweep through the positions is what I think I want. I said I THINK I want. Obviously I'm open to alternative suggestions. And no, changing the motor but keeping the turbo pump is not an option. It's quite specialized. And for a buck - not a bad price to get something that can be repurposed.
Speaking of ponds, I'll be out back cleaning the 105 gallon pond I currently have. Later this year I'm planning on a 1000 gallon pond (approximately). As for filtration, I have that sorted out. Sort of anyway. The water pump is going to be 120VAC from either a dishwasher or a washing machine drain pump. Waterfalls and jets to circulate the water around the pond. And the air bubbler in the middle.
For those extra curious I'm planning a side basin that is filled from the waterfall but not a part of the pond. In that is going to be an ultrasonic mist unit and its mist is going to flow down a different path into the pond. It may be a year before I get that far. Assuming I'm even able to get the pond built in the first place. Back issues. Son-in-law will help, but I still want to be thoroughly involved in the project. Lots of concrete work along with sealing of the pond against leaks.
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