HOLLOW BEARING DESK FANS
Split-Phase Fan Motors- These have two windings. In a Permanent Split-Phase motor (capacitor or inductor), the second winding is the AUXILIARY winding, and it has a higher DC resistance than the MAIN winding. When determining which lead is which, you will start by marking the motor leads A, B, and C. Then take three ohmmeter readings, A-B, B-C, and A-C. You will get a low, a high, and a highest ohm reading. The low reading will be resistance across the MAIN winding, the high reading will be resistance across the AUXILIARY winding. The highest reading will be the combined resistance of both windings in series with each other.
A-B : High
Leads B and C are the ends of the windings, and A is the common. C is the MAIN winding lead, and B is the AUXILIARY winding lead.
Why There Are Two Diagrams for the Same Type of Fan-You will notice that the diagrams can be used for several different fan types, and that there is overlap in the types listed. A 73646 fan uses the 71666 diagram for wiring, yet the 73646-AK uses a different diagram. The earlier 79-series fans, such as the 79648-AK also use the 73646-AK wiring diagram, yet later streamlined-styled 79-series fans such as the 79646-AQ and 79648-AL use shaded-pole motors and thus use the 79648-AQ diagram.
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