Understand motor wiring - HELP.

[st600r]

Replaced motor on dehumidifier with generic motor. SEE attached PDF for diagram.
I am trying to understand how this works. The only thing I know about a CAPACITOR is that it stores electricity. I connected 115v to the BLACK & YELLOW wires thinking I would get the low speed result of 1100rpm's. The motor will not start by itself, but if you help it, it will stay running.
I then assumed that the CAPACITOR shown between the BLUE & WHITE wire was mandatory. Bought a 6uF/370v (because that is all they had). Initially connected it to the YELLOW & BLACK wires from my original hookup. The motor would not start by itself. Same deal, if you help it start it will continue to run.
I then connected the CAP to WHITE & BLACK. The motor started by itself and really took off. Sounded a lot faster than when just the YELLOW & BLACK are hooked up without the CAP.
Next experiment was to connect the CAP to BLUE & BLACK. The CAP "sparked" upon hook up, but the motor would not start.
Assumtions based on my LIMITED electrical knowledge:
The hot side is the BLACK wire, then by picking either the YELLOW or RED wire would complete the circuit and give you the low/hi speeds noted. BUT it will not start without the CAP.
Why does the CAP have to be on the BLACK & WHITE wires?
What is the BLUE wire for?
Doing my best to understand and learn how this works. THANKS for any help you may be able to provide.

[jeff1]

Hi,


Replaced motor on dehumidifier with generic motor

The original one was not available?


SEE attached PDF for diagram.

Was this written on one of the motors?


The only thing I know about a CAPACITOR is that it stores electricity

There are start capacitors and run capacitors. Start caps are often a much higher uF, run caps are often a very low uF. Start caps are in the circuit for a moment to get the motor up and running, run caps are in the circuit the whole time the motor is running.


I then assumed that the CAPACITOR shown between the BLUE & WHITE wire was mandatory. Bought a 6uF/370v (because that is all they had). Initially connected it to the YELLOW & BLACK wires from my original hookup.

Why?....esp since your diagram shows blue to white for the cap.


Why does the CAP have to be on the BLACK & WHITE wires?
What is the BLUE wire for?

By your diagram the blue and black appear connected anyways.....should be the same black or blue to white for the cap.

jeff.

[st600r]

[/COLOR]
Hi,



The original one was not available?

no markings or labels. could not identify what it was. took it to electric motor shop. they opened it up and said it was approx 1800 rpm. told me to get as close as possible.


Was this written on one of the motors?

the wiring diagram is on the NEW motor


There are start capacitors and run capacitors. Start caps are often a much higher uF, run caps are often a very low uF. Start caps are in the circuit for a moment to get the motor up and running, run caps are in the circuit the whole time the motor is running.

OK. I simply picked 6uF because that is what is on the label. Don't know if that makes it a start or run cap.


Why?....esp since your diagram shows blue to white for the cap.

It seems to act the same whether you use the black or blue wire. That's why I was wondering why the blue wire is even there.


By your diagram the blue and black appear connected anyways.....should be the same black or blue to white for the cap.

jeff.

Thanks Jeff.