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I was in search for a motor that I will be able to use in a project which is a part of my studies.

Before I start, just want you to have in mind that for the moment the knowledge I have, is just the very basic things regarding electronics. I edited the question in an effort to make it more accurate and give more clues about the project. I hope is not too much information for just one question.

Very briefly, the project is about an one axis sun tracker. There is going to be a construction made of 2 solar panels (dimensions: 353 x 293 x 35mm, weight: 1,6 kg each) with a square made of galvanized steel angles as a base. 2 photoresistors are going to be installed on the steel frame. Somehow (don't know how yet) this upper part, that I described above, is going to be set in such way so that a motor will be moving it according to where the sun is. An Arduino UNO is going to be used to control the motor according to the light that the photoresistors receive. The project says that a relay should be used to receive the low current from an arduino controller and close to high voltage circuit where the motor is going to be connected. After a small research, I saw many people using also Electronic Speed Controllers and motor drivers for different projects that included motors, so I am thinking that these might also seem useful too.

I thought that the first thing to make clear in order to start buying the things I will need (such as relay, ESC, Batteries, and probably others), should be: what motor would be suitable for my project. At the beginning I was thinking of buying a stepper motor, but then i said “why don't I use a motor from an old device, it might do the job”.

Luckily (or not) i found the motor that you see on the pictures below, which has been extracted from a food blender (Moulinex T71). (I wish I could post more pictures so I can show you more of the motor, but for the moment I can only post up to 2 links per question).

So after extracting the motor and in order to understand how the things would work on my project, I thought of the following questions to ask:

1) How can we be sure what type of motor it is?

enter image description here

2) How can I find out what is the voltage that the motor was built to run on?

At the bottom of the blender device is written: “220-240V – 50/60Hz, 260W”

Where i stay the Elecetric utility is providing 230VAC on 50Hz.

3) Could it be possible to run this motor with a 9V or 12V battery?

I watched this video /watch?v=Q7gw3uDRXPw with title “AAA (1.5V) Battery to 120V or HIGHER” on youtube that says that an 1.5V AAA battery could be used to produce 120VAC (pulsed DC) or higher with the help of a voltage inverting circuit. At the description of the video this is what is written regarding this specific circuit: “Output voltage depends on your input voltage, transformer design (# of turns in the windings), and frequency (determined by capacitor value & input voltage). By taking the HV output and feeding it into a voltage multiplier circuit, very high DC voltages can be achieved."

So I thought that a High Voltage motor could be powered by such circuit by using low voltage batteries.

4) The circuit that @Richard Crowley posted, at least logically, seems to be correct.

Besides the motor, that you can see on the pictures with some notes, there are a few other components connected to it: First of all it is the white power cable that 220-240V runs through it, this cable has one blue cable and one brown cable inside of it. Then there are two switches (lets name them 1st Switch and 2nd Switch). In order to run the motor, 1st Switch must always be closing the circuit. 1st Switch (green arrow) has from one side the brown power cable (input) and from the other side except the output (to the black cable) has also connected a capacitor on it (resistor/capacitor or snubber as you mentioned). 2nd Switch has connected on it the blue cable and the snubber from one side as an input and from the output there is a diode (1N4004, red arrow on the pic). When the 2nd Switch is closing at the first level, the current runs through the diode, but if the switch is pressed harder to reach the second level, the current avoids the diode...in that way 2 speeds are accomplished.

Now let's say that I disconnect the switches and therefore all the components, is the motor going to work without that components? Would be any way to work for my project or should I move to find another motor? ![![enter image description here

Just a few notes:

  • The Steel frame with the solar panels should weight approximately 4-6 kg.
  • The motor should be able to run to both directions, on demand.
  • There are no other parts this is the whole circuit. The rest is just plastic covers, buttons and rubbers for the gaps.
  • Let's have in mind that for the project I will use anything in order to make it work, I mean extra components apart from what the present circuit has.
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  • \$\begingroup\$ Hair dryers might use a 12V dc fan motor using Permanent Magnets. High V coils and large steel core is a clue it is not designed for low current , low voltage. \$\endgroup\$ – Sunnyskyguy EE75 Oct 22 '16 at 18:21
  • \$\begingroup\$ If you make the solar panel with a hole in the middle and arrange the drive so that it acts through the centre of mass then you will have the minimum torque requirement. Bear in mind that even a light wind will exert a considerable force on the solar panel. \$\endgroup\$ – Andrew Morton Oct 27 '16 at 19:58
  • \$\begingroup\$ @Andrew Morton You mean something like this goo.gl/NoFE0O \$\endgroup\$ – Antoine L Oct 28 '16 at 20:30
  • \$\begingroup\$ @AntoineL For some reason I was thinking you were doing a 2-axis tracker. But I meant something more like solar panels where the rotational force is applied through the centre of mass of the panel assembly instead of displaced from the centre of mass. Of course, the image shows a situation where gravity is not of much concern so it isn't supported at the far end. \$\endgroup\$ – Andrew Morton Oct 29 '16 at 15:48
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schematic

simulate this circuit – Schematic created using CircuitLab

  1. First-order guess is that the motor is a series-wound "universal" (AC/DC).
  2. You can't tell just by looking at the motor. You need to look at the entire appliance and whatever additional circuit is connected between the motor and the mains power source.
  3. It is unlikely that motor will work on 6-12V (or even 24V, or maybe even 48V) But no way to be sure without knowing the ENTIRE picture (the rest of the circuit).
  4. The blue component is likely a capacitor (or resistor/capacitor) "snubbing" component. It suppresses arcing across the switch. The small black component is a diode with is probably used as a very crude way of reducing the power into the motor to implement a slower speed.

This is just a guess at what the circuit might be.

You did not reveal anything about your project or why you think this rather low-power but high-speed motor may be suitable?

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  • \$\begingroup\$ Wouldn't you saturate the windings with DC on an AC motor and fry it \$\endgroup\$ – Sunnyskyguy EE75 Oct 22 '16 at 14:23
  • \$\begingroup\$ It is not an "AC motor" it is a "universal" motor that "creates" its own moving field through the brushes, commutator and multiple windings on the rotor. \$\endgroup\$ – Richard Crowley Oct 22 '16 at 14:28
  • \$\begingroup\$ @TonyStewart it's a series wound DC motor, which also works on AC because reversing polarity changes current direction in both armature and field coils, so it keeps spinning in the same direction. \$\endgroup\$ – Bruce Abbott Oct 22 '16 at 15:00
  • \$\begingroup\$ So there must be around 16 armature contact pairs per rev to chop the AC or DC to the rotor windings and reverse coil polarity. got it... I wonder if it an even number of pairs \$\endgroup\$ – Sunnyskyguy EE75 Oct 22 '16 at 15:05
  • \$\begingroup\$ @TonyStewart.EEsince'75. A motor design like the one from OP is suitable to run on AC and DC. If the motor was only suitable for DC is could have a massive stator core (no eddy current problems ). This one however has a laminated stator core to reduce eddy currents when running in an AC situation. \$\endgroup\$ – Decapod Oct 22 '16 at 18:09
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1 and 2. The motor you show is a socalled serial motor. It has been specially designed for the blender and build for 220 VAC. At a lower voltage it will run but not at full power. The motor will also run on DC.

  1. To use this motor on a DC source of 12 V does not pose a problem. Remove the switches and the diode. You can leave the blue capacitor. Then connect the motor with to your 12 VDC source and see it running. Since the proposed voltage for the motor supply is very low compared with the design value it is questionable if the motor can do anything useful. But you can try see and decide what to do.

  2. From the powerline one wire to the stator (coil) in your picture. Then from the stator coil (only one in and one out) to via the brush to the commutator of the rotor. From the other brush on the commutator back to the mains.

In series with this all there you have the second switch controlling the speed. This is done with a diode. When the speed is high the diode is shorted out and when the speed is lower the diode is in the circuit making only half the ac cycle pass.

To reduce the sparking of the motor over the collectors a capacitor is added. That is the blue part in your pictures. It is called a snubber.

In general a serial motor tries to run away. Meaning going into overspeed destroying itself.

For instance when you dismantle a vacuum cleaner motor and remove the fanblades then the motor goes into over speed when reconnected to the mains. Therefore be carefull with serial motors.

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    \$\begingroup\$ I expect that chances of a 220 volt motor doing anything useful on 12 volts are approximately zero. \$\endgroup\$ – Peter Bennett Oct 21 '16 at 23:58
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schematic

simulate this circuit – Schematic created using CircuitLab

The Blue "thing" in the photo is called a "X1-rated Plastic low ESR Capacitor to reduce conducted motor noise below CE and FCC class B ratings.

The diode is a half wave switch.

The series wound rotor and stator commutate stator current direction for each rotor pole with armature brush contacts.

Is it "logically" like a Full Bridge chopped (BLDC) Brushless DC motors with Hall sensors?

almost.

For those of unfamiliar with small DC motor currents in AC hair dryers they they use lower voltage DC motors with the large voltage drop in the heater wires which are shunted or selected to change speeds and heat settings and a diode to create the DC and permanent magnets for low cost.

Similar but different.

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