Do not coil excess cable of different types (i.e. motor power and feedback) together. An efficient transformer is formed at HF. Cable lengths should ideally be trimmed to fit the application. If excess cable cannot be trimmed, it should be laid in an ‘S’ or figure eight pattern.
Using the ohmmeter, find the pair of wires that has the highest resistence as measured in ohms. This will give you your common and lowest speed tap. Using each of these two leads in turn, find the pair that gives you the the second-highest resistance. This should provide you the common and second-lowest speed tap and should also allow you to isolate which of the two leads from the first test is the common.
It is important to keep this struggle between performance and cost in mind when you talk to customers about energy-efficient motor-driven equipment. Yes, efficiency is probably more important to homeowners now than ever, but that efficient operation comes at a price. And motor manufacturers will keep working to strike that balance between motor performance, efficiency, and cost.
Note! Not all drives allow the use of a ferrite sleeve around power conductors. Refer to your manuafacturer’s manual for specific applications.