A logic Question

It happens that amdx formulated :

There is a capacitor between A and C whatever way you look at it. Wot is the resistance BOTH WAYS of the Capacitor directly at the capacitor terminals?

Not necessarily, a coil could (and probably does) connect to point C and A. This drawing shows how a coil could be connected to points A and C.

If I get your question correctly, that would be B to C and B to A. On the drawing B to A is shown as A to B, the resistance depends on the switch position. Pos 3 (H) 265 ohms Pos 2 (M) 230 ohms Pos 1 (L) 192 ohms. Thanks, Mikek

amdx wrote in news:m49bt8$cnj$ snipped-for-privacy@dont-email.me:

Dissected a similar fan lately that appears to have a somewhat different schematic:

-----+ +-----C| phase| | C| | _/ | C| +---o/ o----)-----C| | I | C| | | C| | _/ | C| +---o/ o----)-----C| | II | C| | _/ | C| +---o/ o----)-----C| III | C| | C| | C| 220/230Vac --- C| --- C| | C| | C| | C| | C| -----------------+-----C| neutral

Switches are actual radiotype pushbuttons (OFF-switch not shown). Switch III seams to be connected to the center. I did not check whether it fits for your fan. After all, I have to leave something to do for the interested reader :)

petrus bitbyter

amdx wrote in news:m49bt8$cnj$ snipped-for-privacy@dont-email.me:

-----+ +-----C| phase| | C| | _/ | C| +---o/ o----)-----C| | I | C| | | C| | _/ | C| +---o/ o----)-----C| | II | C| | _/ | C| +---o/ o----)-----C| III | C| | C| | C| 220/230Vac --- C| --- C| | C| | C| | C| | C| -----------------+-----C| neutral

using fixed font

Darn, it doesn't fit the resistances. Thanks for trying, Mikek

I drew a table with your resistance figures: unsigned values are your measurements, signed values are my computations

pos Rab delta Rac delta Rab+Rac Rbc 1 265 71 +336 332 -35 +36 2 230 107 +337 332 -38 +43 3 192 150 +342 332 So, how dodgy is your ohmmeter? It looks like it might be reading about 6 ohms low on the 2K range

This feels like a possible solution to the DC circuit the switch connects a to one of ,, --[71R]----[35R]----[43R]----[192R]--

amdx wrote in news:m4ajn3$7bd$ snipped-for-privacy@dont-email.me:

could

didn't

missing

different

Switch

fits

Little bit surprised and had a second look. IMHO the resistances fit perfectly. The coils, all in series, are between B and C always 332 Ohm.There are three tabs, connected to the ip3t (rotary?) switch. So you have four coil parts, measuring 71, 36, 38, 192 Ohm respectivly take or give some Ohm for accuracy. In the schematic, replace I by 3 and III by

petrus bitbyter

You are right. I somehow thought the resistances ran the wrong direction in value on one set of measurements. After rechecking, I was in error. Ok, I'll take this schematic as the proper wiring for my Lasko Fan.

I posted your schematic and all values showing the minor differences in the values, here.

I'm a little uncomfortable with the differences, but I'm ignoring them for now.

Now, The fan has 8 coils and 16 poles/16 slots. It is my thinking that all poles are energized in all speed position. If that is true, then I would think that at least 4 sets of coils are tapped*.

• not really tapped, a coil is put in the slot then a second coil with less turns is put in the same slot, then a third coil with less turns is put in the same slot. The connections are brought out to the 3sp switch. It all looks like one coil, so I'm speculating.

My next question: With the schematic you came up with and the facts, 8 coils laid in 16 slots. How are the coils connected together and with the switch also connected. My next step is to disassemble the defective fan I have, and hopefully I'll be able to figure it out, but, that's a lot of wire to work through in a tight area. Thank you for the help, Mikek

I think my meter is OK (it's a Fluke) the leads are 0.6 ohms as I recall. Then I used cheap clip leads, so a little more, then I pierced the insulation with a straight pin to get to point B. Also, the switch had to be worked to get minimum resistance. So I'll give some on the measurements. Here's what I came up with.

Here's what I wrote to petrus,

I'm a little uncomfortable with the differences, but I'm ignoring them for now.

Now, The fan has 8 coils and 16 poles/16 slots. It is my thinking that all poles are energized in all speed position. If that is true, then I would think that at least 4 sets of coils are tapped*.

• not really tapped, a coil is put in the slot then a second coil with less turns is put in the same slot, then a third coil with less turns is put in the same slot. The connections are brought out to the 3sp switch. It all looks like one coil, so I'm speculating.

My next question: With the schematic you came up with and the facts, 8 coils laid in 16 slots. How are the coils connected together and with the switch also connected. My next step is to disassemble the defective fan I have, and hopefully I'll be able to figure it out, but, that's a lot of wire to work through in a tight area. Thank you for the help, Mikek

amdx wrote in news:m4d4pm$bf3$ snipped-for-privacy@dont-email.me:

The coils are connected to make 8poles, 4 poles and 2 poles motor for changing the speed. Since the speed of motor depends on number of poles, for 60 Hz it is 60*60/p where p is the number of pair poles. So motor can have 1800, 900 and 450 RPM.

Have you checked the value of capacitor? If cap is dried, there would be no phase shift to run.

Mass

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Thanks for the info, it gives me an idea to work out with pencil and paper. I haven't checked the value of the cap, it is not shorted. The bad motor has a bad pole, meaning every 4th pole does not attract a knife blade. Mikek

I disassembled the motor and disconnected all the wires to the stator. I was marking leads and making a drawing while doing this. I measured all coil resistances. I measured for shorts between coils. I found None. I drew a schematic of how the motor was wired. I reassembled the connections, it still has every 4th pole not acting properly.

The schematic is very slightly different than what petrus had drawn, and that difference is the connection of a coil to the capacitor. I have it at the opposite end than what he does. I think, the way I have it drawn may be correct, because it does put a phase shift on one set of coils verses the other set.

I still do not have any understanding of how the 8 coils plus any extras that are laid in the same slot as the 8 coils I see are wired. The motor has bee varnish dipped so I can't get it apart to see what I want to know.

Mikek

Does this explanation make sense with the following schematic.

I still want to know the exact placement of all 8 coils and how they are wired. I think I need a diagram to give myself clarity. Thank, Mikek

amdx wrote in news:m4j397$g29$ snipped-for-privacy@dont-email.me:

It seems from schematic and your description that winding are on top of each others, the principle is a normal phase shift motor (which has low torque) and the speed is controlled by having more induction in line to increase slip, therefore changing the speed.

Mass

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