wndsofchng06

Non Buick, air compressor question

Recommended Posts

My air compressor is leaking air from the oil fill.....  before I take this apart, does anyone have any ideas... see photos, there's a small line running from the tank to the oil chamber. There's a little hole in the bottom that is suddenly hissing a small amount of air and a little oil too.

20170208_063819.jpg

20170208_063833.jpg

Share this post


Link to post
Share on other sites

I think that line is from the unloader valve but I don't know why it's routed to that part of the crankcase?  Could there be some sort of oil pump there that keeps the unloader valve lubricated?

 

If your compressor is starting up ok when the pressure switch is activated, then you likely have just an annoyance problem where you won't hold air.  But if there's a hard start issue, you'll want to get it fixed.

 

If I had this problem, I would first remove the check valve and see if there's an obvious problem then clean and replace.  Next, I'd attack the unloader valve.  

 

Does the leak leak persist for a long time after the compressor shuts down?  If so, I can't see how you don't at least have a small check valve issue.

 

good luck,

Joel

  • Like 1

Share this post


Link to post
Share on other sites

So after scouring the internet and asking everyone I know, I got no where.  I decided to man-up and just take her apart.  The check valve was a little dirty, cleaned it reasealed and installed.  NOT IT.

 

Took what looks like an oiler off the back of the compressor.  It IS where you add your oil, it is NOT however, an oiler.  It is a wild ball bearing centripetal clutch that regulates the air pressure.  Essentially the blow off valve.  I like to have freaked when one of the bearings fell out!  It not only acts as the over pressure valve, but since the huge flywheel makes the compressor run for several strokes after the pressure switch cuts the power, this bleeds that extra air on each down stroke as the RPMs drop below a certain point!  It's cool!  So I carefully cleaned and lubricated each piece and reinstalled.  She's running great again!!!

 

 

 

  • Like 2

Share this post


Link to post
Share on other sites
5 hours ago, wndsofchng06 said:

I decided to man-up and just take her apart... She's running great again!!!

Are you the same guy that has doubts about rebuilding a nailhead?:D

  • Like 3

Share this post


Link to post
Share on other sites

So the compressor side has been functioning, but now the motor is slow starting and shoots blue green light out of the back.  After about 10 seconds it kicks right up to speed like normal and no arcing.  Brushes maybe?

Share this post


Link to post
Share on other sites

One has to ask if the motor is trying to start against a load?  That is, if the unloader valve or tank check valve isn’t working and the compressor is starting against a pressure load.  One way to tell would be to start it with an empty tank and see if it does the same thing.  You might also check the start capacitor to see if it’s blown.  Just take the cover off and it would be obvious. 

 

Next, you should open up the contactor box and observe it during the start cycle.  Bad contacting could start there and you should be able to see it there as well.  

 

 

Now the brushes.  You have to get into the motor and see if they’ve been consumed.  Blue green fire is from copper sparking but the cause isn’t clear.

 

 

 

 

  • Like 2

Share this post


Link to post
Share on other sites
3 minutes ago, JoelsBuicks said:

One has to ask if the motor is trying to start against a load?  That is, if the unloader valve or tank check valve isn’t working and the compressor is starting against a pressure load.  One way to tell would be to start it with an empty tank and see if it does the same thing.  You might also check the start capacitor to see if it’s blown.  Just take the cover off and it would be obvious. 

 

Next, you should open up the contactor box and observe it during the start cycle.  Bad contacting could start there and you should be able to see it there as well.  

 

 

Now the brushes.  You have to get into the motor and see if they’ve been consumed.  Blue green fire is from copper sparking but the cause isn’t clear.

 

 

 

 

Definitely not starting under load, I can spin it by hand easily.  The tank stays empty, as I rarely use the compressor.  I guess I need to open up the two electrical boxes and see what there is to see......

Share this post


Link to post
Share on other sites

 Can’t recall the application but I once had a motor that would throw fire on starting.  I don’t think it always eventually started.  In fact I think it failed more times than not.  It certainly got worse with time.  I had to dress up the commutator by sawing out some of the mica insulation  between the conductor bars of the commutator.  The copper had worn and the mica was actually higher than the copper.  It worked!

 

One more possibility is that some armature coils have heated up and may have desoldered from the risers of the commutator.  Of course this comes after brushes.

 

 

Share this post


Link to post
Share on other sites
18 minutes ago, JoelsBuicks said:

 Ca

 

One more possibility is that some armature coils have heated up and may have desoldered from the risers of the commutator.  O

 

 

I do hope it's not this bad yet...

Share this post


Link to post
Share on other sites

Could you post pictures from both sides of the motor? I looks to be a split phase start, but that would be a rarity for a compressor. No brushes should be inside, and no commutator. Those are found on "universal" series wound motors that run on AC and DC, like power tools, vacuum cleaners, etc.

 

There should be a centrifugal switch that opens the start winding as the motor gets up to speed. These contacts can get dirty/pitted.

 

Is there a nameplate on the motor?

Share this post


Link to post
Share on other sites

 

does the motor have two large capacitors mounted on top? if it does you have a start switch inside that needs cleaning or replacing. 

Could have just one capacitor

Al

Share this post


Link to post
Share on other sites

No capacitors mounted on the outside.   Sorry all, I am noting your suggestions, I just haven't had time to get back out to the compressor lately.

Share this post


Link to post
Share on other sites

I  finally opened it up.....  the brushes were worn unevenly I have no idea where I'll find a new set of those. But the brush mating surface was also nasty see photos.  one question before I put it all back together there are four wires coming out of the bottom of the motor two of them are tied together inside the cathead the other two run up to the starter mechanism.  why are two just tied off together inside?

20180527_144948.jpg

20180527_144938.jpg

20180527_144944.jpg

20180527_142445.jpg

20180527_142422.jpg

Share this post


Link to post
Share on other sites

The two wires tied together would tell me that you have a motor that is wired for 240V single phase but could be run off 120V single phase.  Those two wires that are connected would normally be labeled #2 and #3.  

 

If you live anywhere close to an electric motor shop, take your old brushes there and you’ll leave there with either new brushes or info on where to get them.  You might even find them online.  You might want to take that armature with you and see if they’ll true it up. It needs a little help.

 

One other thing, if you want to clean the parts, consider using hot soapy water instead of a solvent.  You don’t want to dissolve the varnish or shellac on the windings.

 

 

  • Like 1

Share this post


Link to post
Share on other sites
On 5/27/2018 at 9:47 PM, JoelsBuicks said:

The two wires tied together would tell me that you have a motor that is wired for 240V single phase but could be run off 120V single phase.  Those two wires that are connected would normally be labeled #2 and #3.  

 

If you live anywhere close to an electric motor shop, take your old brushes there and you’ll leave there with either new brushes or info on where to get them.  You might even find them online.  You might want to take that armature with you and see if they’ll true it up. It needs a little help.

 

One other thing, if you want to clean the parts, consider using hot soapy water instead of a solvent.  You don’t want to dissolve the varnish or shellac on the windings.

 

 

Thanks!  I put in a call to a guy that owns an electric motor shop back home, and he thinks he's got something for me.... we'll see.  I cleaned the contacts with a brass bristle brush and electric motor cleaner that I used on the starter and other stuff.  I put heat shrink over the insulation that was looking a bit worn, and will await feedback on the brushes.

Share this post


Link to post
Share on other sites

Cleaned the commutator, new brushes (had to buy larger and file them down but it was only 10 bucks for 10 of them) and she's back on the go. Last photo is the motor in the ford truck frame for size reference. Took 2 of us to lift it.

20180609_152336.jpg

20180609_155912.jpg

20180609_161057.jpg

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...