3 phase pumps, the latest thing.

[Ca++]

I think they are the baby of the group, if keeping with this style. Today it's £6 delivered (<$10) but 12v (standard stuff)

Solenoids, if you need them, are about £4 in this size

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Nitrile hose, around £2.50 a meter
12v timer, for your 12v system, maybe £7.50

 

[420PyRoS]

Title of thread a bit confusing. 3 phase DC? 3 phase is AC.

Brushless DC technically impossible without the use of AC.

Hmm...

 

[Ca++]

Title of thread a bit confusing. 3 phase DC? 3 phase is AC.

Brushless DC technically impossible without the use of AC.

Hmm...

AC is alternating current. Back and forth. This isn't needed to move something. A permanent magnet can move something.
What we have here is electronic commutation. Where DC electromagnets are switched on, consecutively, round and around.

https://www.electrical4u.com/brushless-dc-motors/

In 2 phase designs, the +&- to each phase, might get swapped, to mimic AC. In such cases, pole counts such as 2 and 4 are common. It is in essence an AC motor, with some DC control gear, that mimics AC.

3 phase DC motors tend to have higher pole counts. 1 or 2 dozen isn't at all unusual. Wired alternately. This closer spacing of the poles, reduces vibration. Typically the control gear isn't just firing off and hoping the motor keeps up. Instead, motor position is monitored and the phases switched at the appropriate moment.

It is entirely possible, to have a star or delta wind, and not only apply positive, but also ground. As long as the position of the rotor is known, this can give a smoother hand over between phases. It's even getting common to use a modified sine, to ramp up and down the current more smoothly. Further reducing torque peaks. Or cogging, as it's known.

This cogging is where vibration comes from. In a 2 pole motor, the rotor is expected to move in big strides, while the the 3 phase varients, it's lots of little steps, made with precision.

There is certainly some crossover between the designs, as a motor is a motor. However these little BLDC motors, really are DC motors. Using switching of the magnetic fields position, to promote movement. Not a reversing of the field at fixed points.

 

[420PyRoS]

AC is alternating current. Back and forth. This isn't needed to move something. A permanent magnet can move something.
What we have here is electronic commutation. Where DC electromagnets are switched on, consecutively, round and around.

https://www.electrical4u.com/brushless-dc-motors/

In 2 phase designs, the +&- to each phase, might get swapped, to mimic AC. In such cases, pole counts such as 2 and 4 are common. It is in essence an AC motor, with some DC control gear, that mimics AC.

3 phase DC motors tend to have higher pole counts. 1 or 2 dozen isn't at all unusual. Wired alternately. This closer spacing of the poles, reduces vibration. Typically the control gear isn't just firing off and hoping the motor keeps up. Instead, motor position is monitored and the phases switched at the appropriate moment.

It is entirely possible, to have a star or delta wind, and not only apply positive, but also ground. As long as the position of the rotor is known, this can give a smoother hand over between phases. It's even getting common to use a modified sine, to ramp up and down the current more smoothly. Further reducing torque peaks. Or cogging, as it's known.

This cogging is where vibration comes from. In a 2 pole motor, the rotor is expected to move in big strides, while the the 3 phase varients, it's lots of little steps, made with precision.

There is certainly some crossover between the designs, as a motor is a motor. However these little BLDC motors, really are DC motors. Using switching of the magnetic fields position, to promote movement. Not a reversing of the field at fixed points.

I get it. The flipping of poles is all I'm saying is basically like AC. Sure it's not a "wave"

 

[Ca++]

Yes, there is much in common. These ~3 pumps are quite refined though. Rather than just spin at the mains frequencies demand, they use a micro-controller. The first thing you notice, is the soft start. They take a couple of seconds to reach full speed. This doesn't catch your ear so much. Then you realise, you might not actually hear it at all. They run less power, into less rotating mass. Applying a field with precision, rather than no consideration at all. It's a lot quieter. This positional awareness shows up rpm not inline with expectations. They can see the water ran out, and stop. Also that the rotor is jammed, so they should pause and try again, a few times. These particular pumps don't reverse to clear jams, that I'm aware of. However, if you had pressure in the line, water is coming back anyway.

That's fairly trick, compared to what we have had until now. Better manufacturing tolerances and material choices, coupled to this trick management, has given us the 1 bar needed for standard drip systems. With a pump that fits in your grip, not a crate. It's a huge heap forward, and it doesn't cost more. It costs less.

I'm really impressed by them. The one's I just posted are not ~3 though. They might not offer the full list of tricks. I'm bussin to find out though

 

[Ca++]

Not bad for a tiny pump. The smallest, most basic in the range. No soft start or run dry protection. Not the fancy torque vectoring of a A3 (~3) model. Just a case of 'go' like an AC motor. Stuck to the plastic bath, you could hear it running. It was quiet in my kettle (silent almost) if I kept it away from the sides. By no means bad, but not the refinement of applying the fields in relation to rotor position.

 

[420PyRoS]

View attachment 18876062
Not bad for a tiny pump. The smallest, most basic in the range. No soft start or run dry protection. Not the fancy torque vectoring of a A3 (~3) model. Just a case of 'go' like an AC motor. Stuck to the plastic bath, you could hear it running. It was quiet in my kettle (silent almost) if I kept it away from the sides. By no means bad, but not the refinement of applying the fields in relation to rotor position.

Luckily I've worked with many types of pumps like centrifugal, positive displacement, diaphragm and forms of venturi, plus the pleasure of working on various types of generators and motors. Lately, I've been working for a large manufacturing company that deals with a ton of servo motors/encoders and full systems automation after line setup. Quite something to have that kind of control and adjustment. This stuff always fascinates me, and I'm definitely not the smartest cookie in the jar. Haha!

Servos rock!