Powered by Invision Power Board


Forum Rules Forum Rules (Please read before posting)
Pages:123 ( Go to first unread post ) Reply to this topicStart new topicStart Poll

> Compressor Build, (For use in plasma cutter)
tekwiz
Posted: November 18, 2011 09:51 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




That valve should work as an unloader. You probably need a new check valve, though. I suspect the problem is actually a poorly machined seat where the rubber contacts to make a seal. I could easily remachine that, but shipping would likely cost as much as a new valve. You should fix it, though, air leaks are expensive.
Go to your local factory, hydraulic, or industrial supplier to look for a new one. Small check vlaves are used in many applications other than pneumatics.
Some blowby out of the crankcase vent is normal when the compressor head is under pressure...piston rings never make a complete seal. Another reason to have check & unloader valves. wink.gif


BTW: Nothing says you can't parallel other tanks to your system. Old BBQ propane tanks mounted upside down can be used for this without modification, by unscrewing the original valve. This will leave an NPT pipe thread behind. Mounting the tank upside down takes care of the drainage issue.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
AwesomeMatt
Posted: November 19, 2011 03:24 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




QUOTE
I suspect the problem is actually a poorly machined seat where the rubber contacts to make a seal.


Yeah, from where I looked, it was definitely poorly machined. It looked kind of like someone was cutting a spiral ramp and stopped at one point. Funny thing is, it never failed before, during the life of the old compressor.

Now, it'll drain the tank down to 75 PSI in about a minute.

I think part of the problem is the base of the spring had nothing to sit in to keep it square.. and the two parts of the valve have to screw into each other, more or less guaranteeing that the spring is going to skip away from the middle and then end up at an angle, which of course will leak. Previously I screwed the lower part to the tank, put the spring in, then screwed the upper part to the lower part. Before I buy a new one, I'll try screwing them to each other first, sticking a drillbit up from the bottom to see if I can center the spring, and then screw the pair into the tank last.

I could try machining the top piece where the rubber touches, but not having milling bits, I'd leave a conic profile rather than a flat one. It would be smoother but shaped worse for a seal (a corner can't hold much of a seal compared to two flat surfaces).

*shrugs*. I have a weird sense of thriftiness. I'll think nothing of regularly dropping $100 on a meal for two, just for something to do, but spending $5 on a part that I'm disgruntled about having to purchase feels like I've wasted money and I'm loathe to do it. I know part of it is the thrill of doing it myself, but there's an inconsistent cheapness in play as well.
PMEmail Poster
Top
tekwiz
Posted: November 19, 2011 08:59 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Remachining that seat is a lathe job. It looks like they originally used a 2 flute cutter in the tailstock of a CNC lathe to produce the seat by counterboring the hole. Looks like they didn't dwell long enough at the maximum depth, leaving the roots attached of the 2 chips that were created.
You might be able to fix it with a flatbottmed drill in a drill press. This is a drill bit that has been sharpened with a 180° included angle on the point, as opposed to the normal ~120°. You'd need to know someone who knows how to sharpen a drill that way, though.

Quite likely that valve has been leaking all along, but the outlet valve in the original pump prevented it from being noticed. This would manifest as the compressor cycling with nothing using air.
A properly sealed system should never run unless air is used. My 50's vintage Craftsman compressor never runs even though it's on & up to pressure all the time. Unless I leave something plugged in that leaks, that is. So far, the longest idle period has been over 3 weeks without a startup.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
AwesomeMatt
Posted: November 25, 2011 07:57 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




Getting closer to finished.

Started off by taking apart the check valve and elongating the spring a bit. Maybe that'll help.

Next, I found a place to mount the dishwasher valve and, lo and behold, right where I wanted the bracket, there were already tapped holes and screws in the tank platform, perfectly lined up. AHA! An omen. Everything is going my way today!

user posted image

Next up, I needed a T/Y/E/etc splitter. Hardware store only had females or oversized males. I thought I might be able to make one out of copper pipe, but my copper was either too small or too big. Then I found some kind of screw vent/tap in the plumbing morgue box in the basement. AHA! On a roll now!

Took off the actual tap part, ta da, T-splitter. Figured I'd mount it right to the dishwasher valve but didn't trust my (never tried it before) brazing, so I was just going to connect it with hose. But, I wanted to add a little support, so I cut off an inch of pipe and soldered a band to it so it would stay put. Worked okay.

user posted image

Then cut up the remaining hose and put it all together.

user posted image

Look at me, stimulating the economy, keeping the dollarstore hose clamp industry in business. 9 so far.

Great. Well, the dishwasher valve should be normally closed, err, closed to air, electrically open. So, before I hook up a relay and connect it to the motor, let's test the check valve.

Hrm. That's strange, it's not building above 10 psi and I hear hissing.

I throw a balloon over the dishwasher valve vent, and it inflates in about 2 seconds.

Crap. So much for fate being an agent of completion today.

Few possibilities:

1 - Dishwasher valve, despite looking brand new and unused, is busted, and hence why it was in the morgue.

2 - Dishwasher valve works backwards how I think it does, clamps shut when powered. That would be beautiful since I don't need a relay. (I'm presuming it's 120VAC, it doesn't say on it, so I didn't want to test it yet).

3 - Dishwasher valve can't handle air, leaks like crazy. Abandon ship.

4 - Dishwasher valve is hooked up backwards, only blocks 1-way and I've been using the wrong side.

Oh well, more to figure out.
PMEmail Poster
Top
MacFromOK
Posted: November 25, 2011 08:07 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 13,931
Member No.: 5,314
Joined: June 04, 2006




It should stay closed without power. Otherwise, dishwashers would fill every time the mains electricity went off.

I'd check possibility number 4, and if that doesn't solve it, take the valve apart for inspection (if possible). beer.gif


--------------------
Mac *

"Basic research is what I'm doing when I don't know what I'm doing." [Wernher Von Braun]

* is not responsible for errors, consequential damage, or... anything.
PMEmail Poster
Top
tekwiz
Posted: November 26, 2011 12:10 am
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Yep, #4 is the most likely. The flow should go from the bracket to the bottom fitting....the bracket side having the higher pressure.
Other than that #1 is next.

BTW: Dude, stop buying your brass at the hardware stores. Not only does the selection suck, it's also very expensive...usually double what you'd pay from an industrial or hydraulic supplier, if not more.
Home Depot is the only hardware store with a decent fitting selection, but they're still expensive.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
AwesomeMatt
Posted: November 26, 2011 01:49 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




Okay, partial disassemble. Figured I'd gut the valve while I was at it, just to see how it worked (blowing from either end didn't seem to allow any airflow, but that's just lung pressure).

user posted image

The lower row of pieces all stack in the output tube, in order. Metal washer (where it sits are grooves so it doesn't block air). Concave black spacer thing. Plastic Celtic cross thing with center peg that appears to do nothing. And a mesh bowler hat last (to serve as the bouncer and keep the dishwasher's riffraff out of the valve). Do I need to put any of these back? They rattled when I tested it and I can't see that they accomplish anything for me.

Here's the other (solenoid) side:

user posted image

It appears undamaged. The valve part (donut with plastic), seems intact. The size of the actual hole seems way too tiny. It's pin-sized. The solenoid plunger is on a spring and has a little rubber sponge that covers the middle hole. The slightly bigger hole on the side is where water/air comes in.

Hrm. Now that I look close, perhaps the pin-sized hole isn't for water flow. The rubber seal around the plastic is shaped like a jellyfish, so the whole thing could rise and let water go underneath it and out, as soon as it lifted the plug out. So, maybe the pinholes are just so the pressure can equalize and the solenoid doesn't have to fight suction?

Other than the rattling (hopefully resolved by yanking out everything on the output), it seems to work just fine.

[Edited to add...]

Wait.. no.. I can't see how it actually stops the water/air. The plunger's wimpy spring is nowhere near strong enough to hold back 100+ PSI, is it?

Air coming into the narrow tube puts pressure on the whole bladder thing, either venting directly to the output if it lifts enough to break the conic seal and escape under it, or, through the middle pinhole where it shoves the plunger back. If the plunger leaves the middle hole, air will escape out the other hole in the disk to the output, and a steady stream will leave.

I guess it doesn't matter much. It's mostly likely a working valve that I simply don't understand, rather than a broken valve.
PMEmail Poster
Top
AwesomeMatt
Posted: November 26, 2011 03:56 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




Okay, well, hooked it up backwards/the right way. Still leaks air out the output so fast that pressure pretty much can't build. It's building, but stupidly slowly. I gave up at 25 PSI.

So, *scratcheshead*. I dunno what now. I don't know if the valve was bad, or if its design just doesn't work well (since I can't figure out how it's supposed to work anyway).

Semi-good news is I didn't think the check valve was leaking, but, then again pressure only built up to 25 PSI, so it's hard to say.
PMEmail Poster
Top
tekwiz
Posted: November 27, 2011 12:01 am
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




You need all of the parts except for the screen. That valve uses water pressure to do much of the job. What that tiny plunger does is uncork a passage that allows pressure to build up under the diaphragm(the big thing), which then lifts & opens the main port. On closure, blocking the tiny port causes pressure to build up behind the diaphragm & force it down, closing the main port.
It should work on air, but may require some pressure behind it to close all of the way. If so, then you can't use it anywhere the pressure would be applied gradually. Hook it up to a faucet & mess around a bit, see if & how it works.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
AwesomeMatt
Posted: November 27, 2011 02:12 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




QUOTE
You need all of the parts except for the screen.


Well, I put them back, (they just sat in the output tube, after the valve), but no change. Still doesn't do anything.

Tried powering it up a few times just to see if it needed to seat properly or somesuch, but, nope. Also, doesn't sound all that happy. There's a bit of a rattle to the solenoid when it's left on, which, I presume it would be, non-stop if the compressor was on but motor off. I also wonder if it needs water for cooling.

A more powerful solenoid would make it easier, no? Something that could actually hold back 100+ PSI? Or, hrm. Considering it's not actually controlling any flow except to dump pressure in the line... the hole doesn't actually need to *be* more than a pinprick. I wonder if I just epoxied the diaphragm down (or a ring in its place), if the existing solenoid could plug the tiny control hole in the middle only, and call it good enough.
PMEmail Poster
Top
tekwiz
Posted: November 28, 2011 10:50 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




If you're using it for a dump, it doesn't need a lot of flow...the mechanical ones built onto pressure switches are just tire valves in a fancy stem.
That valve may be designed to work only with water...pilot operated valves like that are sometimes finicky.
The water has no cooling effect.

However, if you're going to use a relay anyway, why not modify one to actuate a tire valve? You can get all of the valve stems you want free from any tire shop or garage...they are replaced every time a new tire is mounted. Strip the rubber off & you get a brass stem that can be soldered to a piece of tubing for hookup & to a metal bracket for the relay. Valve cores are cheap if there aren't any with the stems. wink.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
AwesomeMatt
Posted: November 29, 2011 04:47 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




I'd actually considered that when I saw them at Princess. I doubt the solenoid would be strong enough to hold them open, but, some leverage should make it possible. I'll add that to my contingency list.
PMEmail Poster
Top
tekwiz
Posted: November 30, 2011 11:33 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Just remember that a normally open valve is strongly preferred. One that closes when power is applied. This eliminates any problems with pressure buildup from small leaks & with continuous operation of electromagnetic coils.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
Mike Mills
Posted: December 08, 2011 04:53 pm
Reply to this postQuote Post


Newbie
*

Group: Members+
Posts: 4
Member No.: 36,210
Joined: December 08, 2011




Hi folks,
I ran across this forum searching for the same motor, I am assuming it is AC. The reason I say that is that on some forums (woodworking) everyone says treadmill motors are DC. According to the web some are AC most are DC.
Maybe this is an easy question for people that know.
Motor says 1hp 11.0 amps, 1725 rpm. As given in prior post it same motor, specs, and pictures the same.
Since it was listed as a treadmill motor I assume that the speed can be varied.
I was thinking of using one of these
http://www.amazon.com/s/ref=nb_sb_noss?url...peed+&x=16&y=18
I will be using it as a variable speed grinder. Short usage periods, typically under five minutes at a time.
So, do you think it will work?
Thanks,
Mike
PMEmail Poster
Top
johansen
Posted: December 08, 2011 06:02 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,087
Member No.: 10,912
Joined: September 06, 2007




Any time you see an rpm specified somewhere between 1720 to 1750, or 3450 to 3500 you should assume it is an induction motor. much larger motors will run closer to synchronous speed, which is 1800 and 3600 rpm.

Anyhow, no, you can't vary the speed of an induction motor without buying a VFD.
I have no doubt that some treadmills might use a cheap vfd to drive an induction motor.

You might be able to change it from 1725 to 3450 rpm, it would have one fourth the torque and you would need to run it at half its rated voltage.


--------------------
Can the Ethics Committee have a closed door meeting without imploding from cognitive dissonance?
PMEmail PosterUsers Website
Top
Mike Mills
Posted: December 08, 2011 06:43 pm
Reply to this postQuote Post


Newbie
*

Group: Members+
Posts: 4
Member No.: 36,210
Joined: December 08, 2011




Thanks for the reply.
Guess I have to find another use for the motor. rolleyes.gif Always something to bodger.
I want to get the speed down to 400 rpm or less. A gear motor cost a lot less than the speed control (I don't need much hp).
I assume it IS ac, correct?
Thanks,
Mike
PMEmail Poster
Top
AwesomeMatt
Posted: December 08, 2011 07:41 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 2,965
Member No.: 9,878
Joined: June 21, 2007




You could manually gear it down with gears or pulleys.

I have a 25 year old AC treadmill, it uses a continuously variable transmission based on conic split pulleys with their tension on a spring. You adjust speed by turning a crank that pulls a steel cable that pulls on the entire motor itself which is on a hinge. This pulls the motor and the attached pulley farther away from the other pulley. The extra tension on the belt pushes the split pulleys farther apart, letting the belt fall to a lower level, and thus smaller ratio, slowing the motor treadmill down.

A CVT would probably be like, $40 or something, which is probably double what you paid for the motor.
PMEmail Poster
Top
10100011
Posted: December 08, 2011 07:47 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 1,647
Member No.: 13,441
Joined: February 25, 2008




Dad's got a small moped-type scooter which has a similar transmission set-up, I'm not sure if it operates on the throttle cable or some centrifugal type arrangement though - that does seem to be in quite a small package too.


--------------------
"A drunk man's words are a sober man's thoughts"

From the same company that brought you the Red Ring: Y2K9, Death of the Zunes.
PMEmail PosterUsers Website
Top
johansen
Posted: December 08, 2011 10:05 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,087
Member No.: 10,912
Joined: September 06, 2007




do you need speed control or no?


--------------------
Can the Ethics Committee have a closed door meeting without imploding from cognitive dissonance?
PMEmail PosterUsers Website
Top
Mike Mills
Posted: December 09, 2011 01:38 am
Reply to this postQuote Post


Newbie
*

Group: Members+
Posts: 4
Member No.: 36,210
Joined: December 08, 2011




Matt, that sounds about like a Reeves drive which is on a lot of lathes. It may well be that the scooter used the same type drive.
I don’t really need a speed control just a low speed even 100 would do if it has torque. I was going to mount a 9” diamond plate vertical for honing chisels and add about a 4” diameter section of leather in the center for stropping. I would be able to hone one in a couple of seconds per side at that speed.
I already have a motor arbor adapter and a flex cable so maybe I will use this motor to power a sanding pad on the flex cable.

PMEmail Poster
Top
tekwiz
Posted: December 10, 2011 01:40 am
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




QUOTE (Mike Mills @ December 08, 2011 04:38 pm)
Matt, that sounds about like a Reeves drive which is on a lot of lathes. It may well be that the scooter used the same type drive.
I don’t really need a speed control just a low speed even 100 would do if it has torque. I was going to mount a 9” diamond plate vertical for honing chisels and add about a 4” diameter section of leather in the center for stropping. I would be able to hone one in a couple of seconds per side at that speed.
I already have a motor arbor adapter and a flex cable so maybe I will use this motor to power a sanding pad on the flex cable.

No reason why you can't step down the speed with belts & pullies. However, to go down to ~100RPM is going to require more than one stage. Therefore, a jackshaft will be necessary if you want to use that motor.
For intermittant use, I'd suggest a cheap variable speed drill, with the arbor in the chuck. The drill can be fastened to a wooden or metal cradle with hose clamps. The drill should have enough power for the job, especially given the flywheel action of the grinding wheel.

Why vertical? I find things like that are much easier to see & work with when the wheel is horizontal, given that the action is on the face, not the outer edge. Horizontal operation makes water cooling much easier & more effective as well.


BTW: That type of vari-speed drive is also widely used in milling machines & snowmobiles. wink.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
Mike Mills
Posted: December 10, 2011 03:12 am
Reply to this postQuote Post


Newbie
*

Group: Members+
Posts: 4
Member No.: 36,210
Joined: December 08, 2011




First, my apologies to AwesomeMatt for hijacking his thread.
Tekwiz, yes I was thinking horizontal, forgot before it got to my fingertips.
I can do it with pulleys but that may wind up being fairly expensive. I do have a few but would have to check the size.
But how about this.. and about 1/3 the price of the speed controller.
http://www.surpluscenter.com/item.asp?catn...c&item=5-1677-A
At 4.5 amp (1/3+ hp?) it will have more than enough torque for honing chisels.
It is lower rpm but that’s ok, maybe better. At the outer edge there would still be about 30” of disc sliding past the edge per second. Still only need 1-2 seconds per side.

Do y'all see any problem with it? From general pictures on the web, the shaft should extend at least an inch at least on the other side.
Thanks,
Mike
PMEmail Poster
Top
tekwiz
Posted: December 10, 2011 03:39 am
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




QUOTE (Mike Mills @ December 09, 2011 06:12 pm)
First, my apologies to AwesomeMatt for hijacking his thread.
Tekwiz, yes I was thinking horizontal, forgot before it got to my fingertips.
I can do it with pulleys but that may wind up being fairly expensive. I do have a few but would have to check the size.
But how about this.. and about 1/3 the price of the speed controller.
http://www.surpluscenter.com/item.asp?catn...c&item=5-1677-A
At 4.5 amp (1/3+ hp?) it will have more than enough torque for honing chisels.
It is lower rpm but that’s ok, maybe better. At the outer edge there would still be about 30” of disc sliding past the edge per second. Still only need 1-2 seconds per side.

Do y'all see any problem with it? From general pictures on the web, the shaft should extend at least an inch at least on the other side.
Thanks,
Mike

If you're planning to run horizontal, then yes, that thing should be ideal. I expect the shaft is 3/4" in diameter & enough to mount a sprocket is enough to mount an arbor.
I just don't know about that speed, it's awfully low for diamond abrasive. But slow speed simply means slow sharpening, as long as the pressure being put on the work is the same. You don't want to be using higher pressures because the abrasive isn't the only consideration...you have to protect the bond that holds it to the wheel as well. wink.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
0 User(s) are reading this topic (0 Guests and 0 Anonymous Users)
0 Members:

Topic OptionsPages:123 Reply to this topicStart new topicStart Poll

 


:: support us ::




ElectronicsSkin by DutchDork & The-Force