Is this right?

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rattus

Senior Member
Who among you can point out the error, if any, in the attached diagram of a ceiling fan speed control circuit?
 

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steve66

Senior Member
Location
Illinois
Occupation
Engineer
I'm not sure. At first I thought it was the reverse switch. In general, its the current direction in the start winding that determines the direction the motor goes.

But I think it will work as described, since changing the current direction in the run winding changes the relative current direction in the Aux winding.

Steve
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
One other minor thing I see: They have made some errors where they have tried to tabulate the total capaciatance next to the switch positions.

Steve
 
hey guys, In the medium speed position, the 4 uf is in series with the aux widing. This is in parallel with the run winding and the 4 uf cap is in series with both. I'm wondering if this is enough phase difference to start the fan? Mike
 
It should look like this. The high circuit is wired wrong. The red conductor depicts the correct wiring.

hongsui_fan_sch_lgcocor.jpg
 

rattus

Senior Member
The normally open contacts. What closes them?

This is a four position pull chain switch with the terminals marked L, 1, 2 & 3. The terminals are switched as follows:

OFF: NC
HIGH: L & 1
MED: L & 2 & 3
LOW: L & 3
 

rattus

Senior Member
Give that man a box of Milky Ways and maybe a King Edward cigar!

Give that man a box of Milky Ways and maybe a King Edward cigar!

It should look like this. The high circuit is wired wrong. The red conductor depicts the correct wiring.

hongsui_fan_sch_lgcocor.jpg

Yer right. In the HI position, full line voltage is applied to the RUN winding. In the MED and LO positions, voltage is reduced by the reactances of the 5uF caps. Voltage to the AUX winding is further reduced by the 4uF cap, and the phase shift remains constant.

This just proves you can't trust everything you see on the Net.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090612-2234 EST

The drawing and description maybe correct. We do not know how the reverse switch interacts.

In the high speed position the AUX winding is the RUN winding. Both windings may be identical or may not. I have no idea what the optimization of designing such a motor and control would be.

In low speed and medium speed the windings are as labeled. In low speed one series capacitor from the line is used providing the lowest voltage.

In medium speed two capacitors in parallel provide a higher voltage, but lower than if the two capacitors had been shorted.

Had I designed the circuit I likely would have used switch position 1 to connect to the node of the three capacitors instead of to the AUX winding.

.
 

rattus

Senior Member
Not even a candy cigarette.

Not even a candy cigarette.

Nope 2 and 3 are the same.

Someone is ignoring the switch pattern in the diagram.

There are four scenarios:

OFF: No voltage to anything
HI: Full voltage to RUN
MED: RUN voltage dropped by current through 10UF
LO: Run voltage dropped by current through 5UF

Bear in mind now that pin 1 of the switch connects to RUN, not to AUX. That is the error.
 

rattus

Senior Member
090612-2234 EST

Had I designed the circuit I likely would have used switch position 1 to connect to the node of the three capacitors instead of to the AUX winding.

.

That is the error as already posted. I think you would never apply full line voltage to AUX.
 

quogueelectric

Senior Member
Location
new york
Someone is ignoring the switch pattern in the diagram.

There are four scenarios:

OFF: No voltage to anything
HI: Full voltage to RUN
MED: RUN voltage dropped by current through 10UF
LO: Run voltage dropped by current through 5UF

Bear in mind now that pin 1 of the switch connects to RUN, not to AUX. That is the error.

Sorry I only followed the one line. My bad.
 
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