Yesterday's air compressor score,

[md21722]

Have you tried taking the belts off after the 8 seconds and seeing how hard the pump is to turn? Is the discharge to the tank still disconnected? With the discharge to the tank disconnected, you could determine could be that the pump gets hard to turn or the motor is bad. I have seen pumps that seem to turn fine one second and then later you can't turn them at all by your hand.

 

[redmondjp]

so far the only way i can verify is to pull the safety valves and there is not much pressure on them when i do pull them. if there is an internal valve or unloader function i dont know about it.

Download and read this:

https://www.aepsurplus.com/upload/attachments/Quincy Instruction Manual 1999.pdf

Oh - this has no bearing on your current issue, but you should hang onto that NEMA starter that you said it would be too expensive to get heaters for (something really wrong there - they aren't that expensive and you only need one strip for a single-phase motor). That's a very nice starter and very expensive to buy new.

 

[motofool33]

Have you tried taking the belts off after the 8 seconds and seeing how hard the pump is to turn? Is the discharge to the tank still disconnected? With the discharge to the tank disconnected, you could determine could be that the pump gets hard to turn or the motor is bad. I have seen pumps that seem to turn fine one second and then later you can't turn them at all by your hand.

disharge is disconnected right now so its free flowing air in and air out no restrictions. Turning the pulley after it stops trying to start it doesn't change much.

I want to believe its the motor not being strong enough, like maybe i wired it wrong or something. When i bought it the terminals in the electrical housing were never used it looked brand new. so that makes me believe that maybe there is an issue with the compressor like it needs oil in some places. Im going to explore changing the oil and taking a look at the different valves on the unit.

 

[motofool33]

Download and read this:

https://www.aepsurplus.com/upload/attachments/Quincy Instruction Manual 1999.pdf

thanks i was lookign for that earlier quincys site is not the easiest to navigate for those documents

 

[redmondjp]

I want to believe its the motor not being strong enough, like maybe i wired it wrong or something. When i bought it the terminals in the electrical housing were never used it looked brand new. so that makes me believe that maybe there is an issue with the compressor like it needs oil in some places. Im going to explore changing the oil and taking a look at the different valves on the unit.

Too-thick of oil could be one problem. If you have a magnetic block heater, you could stick it on the side of the pump crankcase. Or shine a halogen lamp on it for an hour or so.

On the motor, are you sure that it is wired for low voltage (208-240)? It might start under no-load even if wired for the high voltage, but definitely would not start with any load on it.

 

[motofool33]

Too-thick of oil could be one problem. If you have a magnetic block heater, you could stick it on the side of the pump crankcase. Or shine a halogen lamp on it for an hour or so.

On the motor, are you sure that it is wired for low voltage (208-240)? It might start under no-load even if wired for the high voltage, but definitely would not start with any load on it.

If you look at the motor plate i wired t1,t3,t5 together to one leg and t2,t4,t8 to other leg with the double end slice screw down connections.



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[redmondjp]

If you look at the motor plate i wired t1,t3,t5 together to one leg and t2,t4,t8 to other leg with the double end slice screw down connections.

Check - so that is not the issue.

One other thing you could check - voltage across the motor terminals (or across the output of the contactor in the motor starter) while it is starting.

Does your compressor pump have an oil pressure gauge on it? You may want to tap into the oil circuit with a gauge to see if the pump is building oil pressure and if so, how high it is - it should be 20-25psi IIRC.

 

[motofool33]

Check - so that is not the issue.

One other thing you could check - voltage across the motor terminals (or across the output of the contactor in the motor starter) while it is starting.

Does your compressor pump have an oil pressure gauge on it? You may want to tap into the oil circuit with a gauge to see if the pump is building oil pressure and if so, how high it is - it should be 20-25psi IIRC.

theres a guage but it hasn't spun fast enough to build pressure.
that or the guage is dead or its not building pressure.

today im gonna stop n grab a new oil filter and drain out the oil and see if its gunked up or not. the oil on dip stick is clean and nice not even discolored.

also noticed one thing the oil pressure circuit can be set to rotate either direction same with the pump earlier i was going off the fact that the arrow on pump pulley turns in the same direction as the motor, but if the oil circuit is the other way maybe thats the reason?

also want to see about taking the unloader towers apart and look for a problem.


another day of playing with it.

 

[redmondjp]

In the instruction manual link I gave you above, it discusses the oil pump rotation and how to change it. I think there are some youtube videos which discuss this as well (link below to one I watched last night):

The compressor is supposed to stay unloaded until oil pressure builds up. There is a shuttle valve on the side of the pump that senses the oil pressure and allows tank (or 'receiver' - valve has an 'R' on it to indicate this) pressure to be applied to the top of the diaphragm in each unloader tower, depressing a pintle inside which holds the valve open. When there is no tank pressure, there is no unloading since there is no need for it.

 

[motofool33]

In the instruction manual link I gave you above, it discusses the oil pump rotation and how to change it. I think there are some youtube videos which discuss this as well (link below to one I watched last night):

The compressor is supposed to stay unloaded until oil pressure builds up. There is a shuttle valve on the side of the pump that senses the oil pressure and allows tank (or 'receiver' - valve has an 'R' on it to indicate this) pressure to be applied to the top of the diaphragm in each unloader tower, depressing a pintle inside which holds the valve open. When there is no tank pressure, there is no unloading since there is no need for it.

I read the manual link start to finish thats where i found the oil pump reverse verbagage.

Heres how im trying to start it now only atmosphere for restriction


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[redmondjp]

Not that it matters much at this point, but it looks like your compressor is setup with control version 'LVD' so you can choose between start/stop and continuous run (using that ball valve). I'm out of ideas here - I can't see any smoking gun here unless the oil is too thick. I'm assuming that the belt tension isn't too high.

 

[MacMcMacmac]

Get an ammeter on it to see what it's drawing at startup. 7-10X rated current at startup is not uncommon. Sounds like an electrical overload to me. Are the capacitors all working properly? You also have to get an air line to that unloader. You will never get it to restart with the unloaders offline.

 

[motofool33]

Oils thick its at least 40 weight or more pulled oil pressure guage turned pump over no oil came out. So i thick its plugged up. Draining now this is after 10mins

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[motofool33]

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[motofool33]

Definitely some sludge, will take some cleaning to sort this out

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[redmondjp]

You will never get it to restart with the unloaders offline.

Are you sure on this? - with the compressor working against no tank pressure, how does it make any difference? Or does it have to do with unloading between the first and second stages? Interstage pressure is 40psi on this model pump, according to Quincy (with final pressure of 175psi).

 

[motofool33]

Not that it matters much at this point, but it looks like your compressor is setup with control version 'LVD' so you can choose between start/stop and continuous run (using that ball valve). I'm out of ideas here - I can't see any smoking gun here unless the oil is too thick. I'm assuming that the belt tension isn't too high.

According to quincy i need one more valve and line to be fully lvd. I didnt dig in too much as i wasnt ready to do that yet just trying to verify operation at this point. Then i can do the extra addons

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[MacMcMacmac]

Are you sure on this? - with the compressor working against no tank pressure, how does it make any difference? Or does it have to do with unloading between the first and second stages? Interstage pressure is 40psi on this model pump, according to Quincy (with final pressure of 175psi).

Yes, restart with air in the tank. Just giving you a heads up. It won't be an issue with an empty tank.

 

[motofool33]

Yes, restart with air in the tank. Just giving you a heads up. It won't be an issue with an empty tank.

So if i can find a way to pressurize the tank before i try to start it it will allow the unloaders to function and lessen the load on the electric motor?

Seems odd that it wouldnt be able to start with no air in tank.

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[md21722]

The tank should have a check valve that won't open until compressor output pushes it open. I am not sure of the validity of this test either.

 

[motofool33]

The tank should have a check valve that won't open until compressor output pushes it open. I am not sure of the validity of this test either.

Im pretty sure this tank does not have a check valve if u look at the pics i put up earlier

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[motofool33]

So maybe tomorrow im gonna remove the oil pump and do some deep cleaning i shop vacumed a bunch of the sludge but not done.

Is there anything special about the bearing or spacers behind the oil pump i need to know before i take it apart? They look simple enough in the manual.

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[MacMcMacmac]

So maybe tomorrow im gonna remove the oil pump and do some deep cleaning i shop vacumed a bunch of the sludge but not done.

Is there anything special about the bearing or spacers behind the oil pump i need to know before i take it apart? They look simple enough in the manual.

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Yes, you need the correct shims to set bearing preload on the tapered bearings. If you trash one or more taking it apart, you be waiting for replacements.

I still think this is electrical. I've seen compressors start and run with no oil in them. Do an amp draw test at startup. You may be doing a lot of work for nothing. The overloads in your starter are adjustable. Are they set correctly?

Don't air up the tank just to get the unloaders working yet. There is no load on the compressor with no air in the tank, but when you try to restart after it has cycled successfully, then you must have the unloaders working.

Quincy often sold these machines without check valves, since the exhaust valve would do the same thing for free. It is another benefit of the unloader system, since if there was any air leaking back past the valve, it would just exit through the open inlet valves back out to atmosphere.

I don't know if you can get the rods up high enough to clear the crankshaft to let you spin the pump over with the motor without moving the pistons by removing the rod caps. If you could, you'd see very quickly if oil pressure was building. It takes about 3 seconds or so of running.

 

[motofool33]

Yes, you need the correct shims to set bearing preload on the tapered bearings. If you trash one or more taking it apart, you be waiting for replacements.

I still think this is electrical. I've seen compressors start and run with no oil in them. Do an amp draw test at startup. You may be doing a lot of work for nothing. The overloads in your starter are adjustable. Are they set correctly?

Don't air up the tank just to get the unloaders working yet. There is no load on the compressor with no air in the tank, but when you try to restart after it has cycled successfully, then you must have the unloaders working.

Quincy often sold these machines without check valves, since the exhaust valve would do the same thing for free. It is another benefit of the unloader system, since if there was any air leaking back past the valve, it would just exit through the open inlet valves back out to atmosphere.

I don't know if you can get the rods up high enough to clear the crankshaft to let you spin the pump over with the motor without moving the pistons by removing the rod caps. If you could, you'd see very quickly if oil pressure was building. It takes about 3 seconds or so of running.

I have to remove the oil pickup its plugged up with that sludge, i will just go slow take one thing at a time off. If i have to wait for parts so be it i have my 5hp running behind this one until i get it working.

The overload is adjustable, i did not try to adjust it today because of the oil sludge i let it drain for few hours then shop vac'd most of the slydge out but im not happy with how much is left neec to clean it out.

But in the mean time i put my mill table back together

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[redmondjp]

Well, it turns out that not starting is a blessing in disguise then, as that sludge issue needed to be addressed. You gotta look for that silver lining sometimes!

I'm wondering if a peek at the rod bearing journals is called for, after finding the plugged oil pickup.

 

[motofool33]

Well, it turns out that not starting is a blessing in disguise then, as that sludge issue needed to be addressed. You gotta look for that silver lining sometimes!

I'm wondering if a peek at the rod bearing journals is called for, after finding the plugged oil pickup.

thinking about it just not sure i want to destroy the bearing getting it out.

 

[motofool33]

Finished the oil sludge cleanup, removed oil pump all looks good, replaced oil pump filled up the case with oil and spun it over a few times and its building oil pressure.

startup problem still there. loud Humm and slow turning of the pump. un hook belt and motor spins up just fine. also the motor case gets quite warm trying to start was still warm an hour later.

turned up the overload to max on the motor start 50amp. same thing just goes for a few seconds longer before the trip.

I am in the process of trying to sort out the capacitors, but none of the meters i have can test capacitance. im hoping there is a meter at work on monday i can use.

But in lieu of that anybody have some good places to buy decent capacitors?

motor run is 30uf +/- 5% 400v 50/60hz
motor start is 270-324uf 250v

prices i see online are all over the place. dont know which ones are good or too cheap.
the WEG ones like it has are damn expensive.

 

[mattblast]

I found that the best prices for capacitors is Home Depot. They don't stock them but they are available on the web site. You get free shipping to the store.

Here is an example.

Packard 440-Volt 35/5 MFD Dual Rated Motor Run Round Capacitor
http://thd.co/1oZqL8g

 

[motofool33]

So decided to take motor to repair shop, tested capacitors they seem good windings good but contact switch inside was broken. It was supposed to arrive today will update when i know more.

Stupid switch was 180$

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[Kmaysob]

subscribed!

 

[motofool33]

Picked motor up he says its all good, will try it in next couple days

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[motofool33]

https://vimeo.com/160536711

After new contact switch fires up without issue. Gotta order some new gaskets for the exhaust port and side plate gonna run it for a while and dump the oil

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[cptn_zippy]

Congrats!

J

 

[littleponderosa]

Nice work dude.

Bill

 

[cosmopedro]

Seriously good deal, sir!

I'm glad you're gonna be paying the power bill...!

 

[motofool33]

This! Coupled with "yes, a 7.5HP vs. a 10HP will give you less output, but unless you're planning to hold it up on a cushion of air you'll never outrun the 7.5!!!

Plus, unless yer mattress' stuffed with cash think of the savings... these puppies like a steady diet of moving electrons while they're supplying us w/tons of air!

This is why i went down to a 7.5hp plus i got the motor for cheap 250$

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[AZpilot]

I would try the phase modulating dynomodulator with phase induction first.

 

[cosmopedro]

https://vimeo.com/160536711

After new contact switch fires up without issue. Gotta order some new gaskets for the exhaust port and side plate gonna run it for a while and dump the oil

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Gotta love that sound - kinda like yer favorite cat purring in yer lap after work... or that ol'hound dog lettin' you know someone's in the yard.

OR, the bigger version of a cat - spelled with a capital 'C', diesel powered, w/5" dual pipes pulling out of a log lot loaded!!

Either way - GREAT thread! Thanks for documenting!

 

[CNGsaves]

^ ^ ^ +1 for SWEET Sound of Success !!

Have to LOVE Lifetime air that you'll get from Quincy 370 running single phase.

I'd say your setup qualifies as . . . . YOU **** !!!

 

[G_P]

I was just going to recommend that you check the switch in the motor, but it seems you got that sorted out.

Sounds like a machine that will provide you with tons of air for decades to come! Great work!