Air compressors maintenance and repair


Old 04-21-19, 04:32 PM
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Air compressors maintenance and repair

Hello, I found an old laydown compressor. I've been wanting a slow rpm unit that will last for years. My issue is I have a knowledge void on compressors maintenance and repair. Here is what I have it runs on 220 or 110, I do not know what oils to use when to oil electric motor or how often. I need to learn how to make sure the cut-off switch is working and any other knowledge I should have to keep this in good working order you for y help Joe
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Old 04-22-19, 03:08 AM
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Welcome to the forums!

Does the unit currently run? If not does the pump turn by hand?
Most electric oils don't take oil but the air pump does. They sell a special compressor oil although if I remember correctly you can also use non detergent 20 weight motor oil.
Old 04-22-19, 07:15 AM
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That looks like a good unit if it works.
I can't read the nameplate under the motor but the unit could be a Dunham Bush brand based on the "D" and the color.
They are mainly a commercial equipment manufacturer and made refrigeration compressors and units as large as ones in ice arenas and grocery stores.

The motor appears to be an old induction start type.
The ASME tag on the tank puts it's age at being mf'd in 1984 but that type of motor has not been in widespread use since the 1960's.
If it is an induction motor it would have brushes for starting which has a fair amount of starting torque but with a higher amperage than a capacitor start motor.
If you can get a clear picture of the motor name plate it would give us a better idea about the motor.
A different camera angle or lighting will allow the numbers ot be seen.
The 110 volt amperage rating for that 2 hp motor is 22 amps which would make operating it at 240 volts a better option.
I can not make out the 240 volt amperage.

It is rated at 2 hp but you can not compare that to the amperage rating of current motors.
The hp rating of current motors is not the long term running hp but the maximum developed power just before staring on fire!
I would say that what you have would compare to a modern 5 hp rated motor.

It is also has a two stage pump which is only found on high end units and will deliver a higher volume of air at slightly less amperage that single stage units.

I would suggest that you hook it up temporarily to see if and how well it works.
The wiring for sure would need to be all replaced with the proper type and size.
it was likely connected to operate at 240 volts but you would need to carefully check the switch wiring and motor connections before trying it.

Specialty "compressor oil" would be a waste of said 20w or 30w non-detergent would be good to use.
Old 04-29-19, 08:42 PM
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Runs well I ran for a short time on 110 but noticed at 60 psi it started to labor so i unplugged and found out its wired for 220 which i will run it on.
Old 04-29-19, 08:55 PM
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Schultz pump was mentioned also for a brand I played with the pics to pull out the info see if this helps
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