Hoover Convertible Motor Troubleshooting

[hooveru4089]

I have an older Convertible that runs perfectly smooth - except when I first turn it on after sitting. For the first few seconds of running after sitting, it sounds almost like dirt being picked up, but it is definitely coming from the motor as I hear this noise even if the base is up off the carpet when I turn it on. After a few seconds, the noise goes away and it just purrs. I did not notice anything obviously unusual when taking the motor apart and I have been regularly lubricating the bearings. Any input/troubleshooting tips would be greatly appreciated.

 

[vacuumlover]

Could be the possible start of warn bearings?

Or a slightly out of shape fan? eg. One of the blades slightly bent thus causing it to vibrate slightly upon start up?[this post was last edited: 3/8/2016-14:36]

 

[hooveru4089]

It is not quite a vibrating sound, and I have a washer between the fan and the bearing which should eliminate vibration. It almost sounds like a bunch of scraping noises inside the motor. It's not that loud at all; I just notice it and it seems to be progressing.

 

[vacuumlad1650]

Fans sound like they are rubbing mixed with bad bearings. They get mis-shaped over time of sitting

 

[kirbyvertibles]

maybe what you are hearing is the electrical arcing of the carbon brushes at first?

 

[hooveru4089]

@kirbyvertibles:

It sounds like that could be it. Is this something I should address soon? The cleaner runs fine otherwise, just purrs like a Hoover should.

 

[hooveru4089]

I should have mentioned previously that this is an intermittent problem; I used it yesterday and did not hear the noise.

 

[MPN]

Hi,

It's likely a stretched area on the belt, as the vibration/noise ceases after the belt warms up.

 

[hooveru4089]

@MPN: There is definitely not any vibration nor is this a vibrating noise. I don't mean to dismiss you, but it definitely sounds more like arcing, as kirbyvertibles suggested.

 

[MPN]

Does the noise change with the belt removed???

 

[MPN]

"I don't mean to dismiss you, but it definitely sounds more like arcing, as kirbyvertibles suggested."

Brushes arching on the commutator makes a "hissing" or sputtering sound if the brushes and/or commutator are really worn.

Another thought . . . If the brushes are really worn down to where the spring tension is greatly decreased, the brushes will bounce especially if the commutator is very worn or out of round. This would explain the noise at start-up, that diminishes afterward as the brush float dampens out.

 

[hooveru4089]

I sometimes do hear the noise when the belt is removed. It is definitely more of a "sputtering" sound or a bunch of little scraping sounds. How would you recommend that I go about diagnosing this? What should I check for?

 

[blknblu]

A mechanics stethoscope could be used to isolate the noise.


The end is is a long hollow tube. For electrical, I put a piece of clear tubing  on the end.


Have to be careful around electricity you know.


They are less than $5 at Harbor Freight ..


 

 

[hooveru4089]

Those tools sure are useful…

…but it seems pretty clear to me that the noise is coming from the brush/armature area. I would like to know if I should disassemble the motor and, if so, what I should examine inside the motor and what I should do depending on what I find.

 

[vacuumlover]

Could be a small build up of dust on the brushes/commy.

 

[hooveru4089]

How would you suggest I clean it?

 

[hoovercelebrity]

Can you post any pictures of the machine? How about a model number? Have you tried completely rebuilding the motor instead of hypothesizing about what's wrong? That's what I do with most all of my machines, and they all run very nicely.

 

[hooveru4089]

Here are some pics:

Close ups of armature, brushes and lower bearing. Motor was very dirty at first; I had to vacuum it out. The model is 719. Let me know what you think.

 

[MPN]

Hmmmmmmmmm ? ? ?

From shat I'm seeing in the first photo, the shaft seems to gave a blue tinge indicating overheating due to lack of lubrication. This could very well be your noise!

While you have it apart, if you have access to a lathe, check the commutator for out of round. If it is out of round, do a few fine cuts just enough to re-round it.

Oil the hell out of that Oilite-bronz bearing or bearings with synthetic oil prior to re-assembly.

Also, REMEMBER to re-install the brushes in the same holder and position as removed, so they don't chatter and/or ark . . .