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diagnosing problems / where to buy air compressor parts? [Merged threads]

diagnosing problems / where to buy air compressor parts? [Merged threads]

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  #1  
Old 10-25-09, 05:00 AM
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diagnosing problems / where to buy air compressor parts? [Merged threads]

i've been looking for a cheap way in to a good compressor, and i came across an ad for one that needs repair.

i haven't seen the compressor yet, but my best guess is that it is a curtis 60 gal horizontal tank 3hp model 3ht6. it is advertised as needing reeds. assuming that this is the case, the compressor should run fine and build up a little pressure, but not a lot, correct? is there a place you can buy reeds for this online?

also, it is advertised as a 3 phase motor, and as i only have residential single phase power, i would need to find a phase converter. this is not going to be used commercially... let's call it... aggressive homeowner use for auto repair and bodywork. based on this, is a static phase converter acceptable? i've found them for sale on places like ebay for $60 to $160 for 3-5hp converters. just wondering whether this would work for this compressor.

thanks.
 
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Old 10-25-09, 05:06 AM
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static converter for air compressor?

i'm wondering whether a static convertor will work for an air compressor motor. i've also posted the details in the tools section with another question:

http://forum.doityourself.com/tools-...ml#post1640466

as i said in the other post, i'm not using this commerically, and being a 60 gal, it won't be cycling a lot - many times once a day, other times when i am out there working on a project, it may happen more often, but not frequently. i'm just wondering whether this would work, or whether i will have to end up looking for a single phase one.

thanks.
 
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Old 10-25-09, 05:51 AM
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Please post questions on the same problem in one thread.

It does not make any sense to install a phase converter in order to be able to purchase a cheap broken compressor.

Good air compressors are very inexpensive especially in relation to the cost of fixing the used one and buying a phase converter.
Read the sticky at the top of this topic for more info.
 
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Old 10-25-09, 09:56 AM
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A used or rebuilt single phase motor will be no more expensive at a salvage store than you can get a static converter for.
 
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Old 10-25-09, 11:34 AM
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You can able find 3 HP single phase motor without much issue but just becarefull which type of 3 HP motor you will get and once you get over 3 HP most of them useally wired on 240 volts and the cost of 3 to 5 HP single phase motor can justifed over getting phase coverter.

Check with motor repair shop sometime they will have rebuilt or used motor on hand for reasonable price as well.

Merci.
Marc
 
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Old 10-26-09, 07:05 AM
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i actually split these because the post in the tools section was asking where to buy parts online (particularly reeds) for compressors as this is the stated problem with it. i searched for quite some time and did not find anything. i had found a post where someone in that forum diagnosed a broken reed problem recently, so i had hoped there would be people with knowledge about where to buy the replacement parts. the post in the electrical section was to determine the functionality of a static phase converter, as they are very inexpensive. if it would work, then the compressor may well be a good deal. if a rotary phase converter is required, then it's not a practical solution.

Originally Posted by GregH View Post
It does not make any sense to install a phase converter in order to be able to purchase a cheap broken compressor.
the compressor is being sold at $150, which is a whole lot cheaper than the new retail. i haven't gone to look at it yet to determine the condition or any other issues. what i'm trying to do is get all my ducks in a row before i make any purchases. i can't say how most people do it, but i tend not to drop cash first and wonder how it works after the fact. i found new static phase converters with a 3-5hp rating for $60-$160 all over ebay. in my mind, that's not a whole lot of cash if it will make this work.

Originally Posted by GregH View Post
Good air compressors are very inexpensive especially in relation to the cost of fixing the used one and buying a phase converter.
i haven't found any new 2 stage compressors anywhere for under $1000 - the big box stores sell them for about $1100-$1150 including tax. i had considered a 60 gal single stage, which can be had for about $500 including tax, but that's hardly much of an upgrade over my 20 year old 5hp 25gal, unless i can get one used for dirt cheap. the only real upgrade would be going away from my oilless, which will drastically cut the noise.

i figure if i can get a 2 stage for a deal, it will serve any needs i may ever have. for relaxation / hobby i do metal fabrication (i have built equipment trailers, snowmobile trailers, farm implements, and other similar items). I also have torn down and completely rebuilt vehicles in the past - a hobby i hope to take up again now that my new garage is almost completed. i'm not just buying a compressor to monitor the tire pressure in the family sedan. buying this compressor, replacing the reeds, and installing a phase converter would have only totalled up to around $250-$300, which in my mind seems like a very good deal, which is why i posed the two questiosn to start with.

Originally Posted by GregH View Post
Read the sticky at the top of this topic for more info.
i've read through the sticky, but to be honest, it didn't tell me much if anything i didnt know from past experience and research - though i will say it is a good reference for someone just learning. really, i only posted two simple questions:

1. does anyone know any online retailers of compressor parts (particularly reeds for a curtis rotary compressor)

2. will static phase converters work effectively for a 3hp compressor motor, or is a rotary converter required (if static works, great. if rotary is required, then it's a no-go due to cost ineffectiveness)

i generally try to keep all my forum posts fairly short, because it has been my experience that long posts are often not fully read or comprehended - most people want cliff notes. i recently had the same problem in the electrical forum here where i actually got a downright rude reply from a regular contributor. i then had to write a novel as i have doen here to explain my life story in order to get an answer to the original question.
 

Last edited by lost_cause; 10-26-09 at 07:07 AM. Reason: edited for readability
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Old 10-26-09, 08:31 AM
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Well, yes, I did answer more questions than the number of question marks in your post but you appeared to be open for discussion but obviously not.

I will expand on what I said though.
The Curtis unit you are looking at is no doubt a quality unit and if you can make it work with a simple repair you would have a bargain.
The only thing you may have to get use to is that unit is designed for continuous running.
You turn it on and it cycles an unloader to control tank pressure.

My experience with affordable static phase converters is that they are not reliable.
I have used these connected to three phase refrigeration equipment and ice makers in remote fish camps and their lifespan was in some cases measured in weeks.
The long term fix was rotary converters but they are very expensive and likely out of the range of your project.

If you were to consider economics and reliability, as others have suggested, a quality industrial motor would be a good match for that Curtis.
You would need a 1725 rpm motor and not an inexpensive two pole 3600 rpm one............It wouldn't stand up.
Only you can then decide if buying and fixing up a broken compressor is worth it.

Also, keep in mind that a simplistic question will get a simple answer.

Curtis info
 
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Old 10-26-09, 09:13 AM
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I do not believe that a static phase converter is appropriate for use with this (or any) compressor. The reason these units can be had for so cheaply is that unlike a rotary converter they do not actually produce three phase power. They mimic three phase for a brief moment by discharging a capacitor to get the motor started (just like the start cap on a single phase motor) then continue by powering only one of the three phases at a time. This effectively reduces the output of the motor to about 2/3 of its rating and operates it in a way that it was never intended to be used because torque is only being applied at one point in the rotation. It's like pulling off two or three of spark plug wires in your car engine; it will run just not like it's supposed to. This imbalance in load eventually will burn out either the converter or the motor. It may last a long time given your intended low duty cycle, or it might not. If you just want to get by with the setup then go for it, but if you want something that's going to last get a better converter or swap the motor.

A rotary phase converter or "motor generator set" produces a much higher quality three phase source, however as you've seen quality comes with a price. At this price point it is better to simply replace the three phase motor with a used single phase motor. It's generally easy enough to find single phase motors in the 3-5hp range that personally I wouldn't bother with the converter.
 
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Old 10-27-09, 07:17 PM
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actually, i'm always open to discussion on most anything - the only problem was that this had headed totally away from my original question. i really wanted to know about the functionality of a static converter so i could better weigh my options. it just got headed in the direction of replacement motors or completely different compressors without giving me any information on converters that i was looking for.

now that i've got some feedback i can discount the static converter route and consider a motor swap - if that turns out to be necessary. after further mails to the seller, i'm not sure whether it is 3-phase or not. once i go look at it i'll know that for sure. the model number i got was ev476, and i can't even google that.

just in case i do need to look for a single phase motor, you mentioned to look for a 1725rpm industrial single phase motor. does it have to be right on those nymbers, or can there be some variation in the rpm and/or hp numbers? also, what is a ballpark price i can expect to pay for an item like this?

thanks.
 
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Old 10-27-09, 08:24 PM
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It is pretty easy to find single phase motor for that size the 3 to 5 HP size without any issue at all and they do come in few diffrent verison to suit the need.

Merci,Marc
 
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