Mach III plus 13.5 ac fan running backwards?

wnjj wrote:

red31 wrote:
Wax, tell us how a capacitor is used to create torque in AC motor?

In short, a capacitor creates a 2nd phase. Here's a pretty decent page to help explain this. Refer to the capacitor-start and capacitor-run motors:
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-13/single-phase-induction-motors/

that's it
Capacitor-Start Induction Motor
'The result is that more starting torque is available for heavy loads like air conditioning compressors.'

red31 wrote:
Wax, tell us how a capacitor is used to create torque in AC motor?

In short, a capacitor creates a 2nd phase. Here's a pretty decent page to help explain this. Refer to the capacitor-start and capacitor-run motors:
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-13/single-phase-induction-motors/

Wax, tell us how a capacitor is used to create torque in AC motor?

sayoung wrote:
I pointed out how swapping run & start reverses these motors.

Like I said up above there are wires you can swap.
oh and I even understand WHY this happens. but that is because I know Eli the Ice man.

dougrainer wrote:

traildog wrote:
I called my electrician brother and he was stumped
As well. He asked me if all power had been disconnected while installing and after installing the capacitors (I replaced both).

I disconnected all power including the battery and waited for an hour. I fired it back up and now it’s running correctly.

Fluke? Maybe but, it was the suggestion from my brother that save me from buying more unnecessary parts.

Thanks for the help here.

TD

Disconnecting 12 volt and 120 power had NOTHING to do with fixing your problem. ALL a capacitor does is BOOST the start up needed power. Did you ever check the separation gasket like I asked? Doug

I pointed out how swapping run & start reverses these motors. Only way I see this could happen ( reversing on its own ) is somebody WAS working on the wireing or as you say a baffling problem which I honestly don't know about as I only worked on couple of rv units & only the electrical/refrigerant side on top. I am not saying OP worked on it but during my long HVAC working days saw a lot of really messed up units that had simple repairs until repairs attempted by an unknowledgeble person that few confessed to.
Maybe the OP's rv is haunted :B this would make an episode of that ghost hunter reality show

ajriding wrote:

schlep1967 wrote:
If it was mine...I would switch the wires around and it will run the other way.
I wouldn't tell somebody else to do that though.....

For Alternating Current motors there is no such thing as backwards wiring. There is no positive or negative, both wires are both positive AND negative (not the correct technical description) that alternate 60 cycles per second (dont wet pants if this is not technical enough...). Switch wires and the motor runs the same direction..

That is simply not correct or to be more accurate it is at best a half truth.

Most A/C motors and some DC motors have two windings.

Oh SOME A/C motors there is a terminal box and if you flip two wires in that box the motor turns the other way.

However said before I do not believe that is the O/P's problem

I think the motor and blower are operating properly but the plumbing is wrong.. a ceiling cover on backwards and possibly a baffle out of place. (Am sitting under a Coleman A/C as I type)

traildog wrote:
I called my electrician brother and he was stumped
As well. He asked me if all power had been disconnected while installing and after installing the capacitors (I replaced both).

I disconnected all power including the battery and waited for an hour. I fired it back up and now it’s running correctly.

Fluke? Maybe but, it was the suggestion from my brother that save me from buying more unnecessary parts.

Thanks for the help here.

TD

Disconnecting 12 volt and 120 power had NOTHING to do with fixing your problem. ALL a capacitor does is BOOST the start up needed power. Did you ever check the separation gasket like I asked? Doug

I called my electrician brother and he was stumped
As well. He asked me if all power had been disconnected while installing and after installing the capacitors (I replaced both).

I disconnected all power including the battery and waited for an hour. I fired it back up and now it’s running correctly.

Fluke? Maybe but, it was the suggestion from my brother that save me from buying more unnecessary parts.

Thanks for the help here.

TD

ajriding wrote:

schlep1967 wrote:
If it was mine...I would switch the wires around and it will run the other way.
I wouldn't tell somebody else to do that though.....

For Alternating Current motors there is no such thing as backwards wiring. There is no positive or negative, both wires are both positive AND negative (not the correct technical description) that alternate 60 cycles per second (dont wet pants if this is not technical enough...). Switch wires and the motor runs the same direction.

On a Direct Current motor, like your vent fan, you can switch directions by switching wires, because DC does not alternate.

So, your A/C motor which runs off AC cannot be run backwards.

You can get a backwards fan blade, but these likely do not even exist. The motor runs only forward. The reason to wire it correctly is so the casing of the motor is not "hot" and cause electrical hazards if touched by a person also touching a ground, where the electricity could flow through your body...

Swap the Run with the Start lead on the Run Cap & it is now running reversed.

ajriding wrote:

schlep1967 wrote:
If it was mine...I would switch the wires around and it will run the other way.
I wouldn't tell somebody else to do that though.....

For Alternating Current motors there is no such thing as backwards wiring. There is no positive or negative, both wires are both positive AND negative (not the correct technical description) that alternate 60 cycles per second (dont wet pants if this is not technical enough...). Switch wires and the motor runs the same direction.

On a Direct Current motor, like your vent fan, you can switch directions by switching wires, because DC does not alternate.

So, your A/C motor which runs off AC cannot be run backwards.

You can get a backwards fan blade, but these likely do not even exist. The motor runs only forward. The reason to wire it correctly is so the casing of the motor is not "hot" and cause electrical hazards if touched by a person also touching a ground, where the electricity could flow through your body...

You are correct for most AC motors. But, I had to replace the Condensor Fan motor on my home AC unit a few years ago and the replacement motor came with instructions to USE a Yellow wire connection IF the motor ran in reverse to get the correct operation. But, RV AC units do not have such wiring. Doug

PS, remember the OP had NOT touched anything on his RV AC unit and he assumes it is running in reverse. I still maintain his divider plate has fallen down and is bleeding air.