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Is there any preferable or possible way (i am still recognizing the borders),

To have set of equipment, where we would have 1phase, 230 V brushless electrical motor, (with the ventilator on the shaft), which speed would be controlled through RaspberryPi, (not through VFD?)

A design based on SSR (with zeroTime OptoCoupler + Triac) + additional OptoCoupler for security of 5 V pins.

It seems that:

  1. Universal Motor may work (but here we have loud brushes)

  2. Split-phase capacitor motor This one can work with relays + properly counted capacitor

  3. Split-phase motor

  4. Shaded-Pole motor Those are probably not controllable without Autotransformator

What kind of engine would be my dreamed (Induction?) sollution, what are limitations of such solutions?

maybe a

A brushless motor is constructed to be a synchronous machine, but the rotating field is timed to match the position of the rotor to generate torque.?

from What does "Brushless DC is an AC induction motor with built-in speed feedback" mean?

is that possible?

hkjz
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  • At 230V, easiest is an AC induction motor + VFD. Above half a horsepower, 3 phase induction motor + VFD for smoother power. For BLDC, drop the voltage to 48V or below + BLDC speed controller. –  Mar 17 '20 at 01:01
  • To determine the preferable motor and controller, you first clearly describe the load. Is "ventilator on the shaft" the only load or is that used only to cool the motor. What is the desired maximum and minimum continuous operating speed? How much power is required at the maximum speed? Could the motor be require to operate continuously (an hour or two at a time) at any speed? Why do you want to design everything rather than purchasing a VFD or some other type of controller? –  Mar 17 '20 at 01:07
  • @BrianDrummond, you said 'AC induction motor'. Which one? Single phase ac motors: 1. Split-phase motor 2. Split-phase capacitor motor 3. Shaded-Pole motor 4. Universal motor @ CharlesCowie - a load is the fan, a ventilator. The motor i have so far, is a Split-phase capacitor motor with Power Max is of 135 W, 4 mF. Maybe i will need to change the motor – hkjz Mar 18 '20 at 09:14
  • Universal motors aren't induction motors, and shaded pole's inefficiency makes it unattractive above a few watts. Pick any of the others, or go straight to 3 phase, probably easier to find a suitable VFD. –  Mar 18 '20 at 10:18
  • To respond to comments, you must write a separate comment to @each person that you want to see the comment. @[space]person does not work. –  Mar 18 '20 at 16:19

1 Answers1

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For a fan load that requires only 135 watts, a single phase induction motor with a variable AC voltage would be least expensive alternative for continuously adjustable speed control. A split-phase, capacitor-run motor would be fine. A shaded-pole motor would also be ok. A split-phase capacitor-start motor would not work, because the capacitor might not disconnect when the motor is started or might re-connect when the speed is reduced. A split-phase motor with unspecified starting method would probably be a motor with two windings of different inductance and winding resistances. If you could find such a motor, it would probably work. Such a motor with a switched winding would not work.

For additional information about controlling induction motors with variable voltage, look at: Speed control for PSC induction motor.

A universal motor would work, but they tend to have much higher speeds than induction motors.