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compressor motor question

SGKent

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Maybe someone will have an answer. First after seeing the prices of electric motors these days I am still trying to get my heart restarted. The last motor I bought was about 7 or 8 years ago and about $90 for a descent motor. Same basic motor today is like $450. Good grief what happened? And, finding used ones just didn't come up much. Maybe my search powers are weakening.

We have a craftsman compressor 919.186430 that uses a motor labeled as MO-3019-2. Best guess is it was made by GE in the USA probably 10 years ago. I picked up a used newer Craftsman compressor 919.195412 and in comparing the specs the pump, pulley, flywheel and all other componets they are exactly the same as the one I have had for 10 years except that the output is about 2 CFM less. Probably RPM. The motor in my old one is 5 HP and the new one is 1.9 HP. (Yes I know they lie on the HP ratings however I do believe that the old motor is more powerful while the new one is probably more efficient). Anyway, I was trying to find what the actual specs were on the MO-2019-2 motor so I could compare it to the newer compressor which uses a Z-D20620 motor. Any place I try to look up a MO-2019-2 motor it substitutes in a Z-D20620 motor as the replacement so if I had to replace the old motor it looks like I would lose 2 CFM or about 25% of the output. Anyone know the answer to what has gone on in motors or does any one have a really good source for air compressor motors that will cross that 5 HP motor to an equally powerful motor instead of this 1.9 HP motor? Devilbliss made the units for Craftsman before K-Mart stepped in and bought Sears. I am hoping to keep my eyes out for a good used bolt in 120/240 single phase motor that will bring this new compressor up the 25% without going broke. Thanks in advance - Steve
 
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rwhite692

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The motor that Sears lists as a replacement (Z-D20620) is 3HP.

The "5HP" proclaimed on the compressor belt guard decal is the "when energized by a bolt of lightning" horsepower number. Only motor plate HP matters.

A quick search of Ebay shows that you can get a (true) 3HP LEESON motor, 56Y frame, 3450 RPM, 230V single phase, 5/8" shaft, for $200. No tax, shipped free.

Question is, is the rest of the compressor in good enough condition, to be even worth sinking $200 into?

There is no reason for you to try to put a (true) 5HP motor on that compressor.

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SGKent

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shorted winding. Verdict was in today - that is why it pulls so much on start. Took it to a motor shop. Unfortunately the base is no standard and is a pivot base. They could not come up with a motor that would mount in the same location unless I did some fabrication and weldiing. Since I would have to pay for a welder to make this work with any of the standard base motors we have some decisions to make.
 
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SGKent

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I rebuilt the motor and put in new bearings. Tested with a meter no shorts and resistance was the same. Could be bad under voltage - I don't have a megger. It runs smoother and quieter. Still blows the breaker occasionally on start but that is 15amp. Doesn't blow the 20 amp. Found a new spare on Ebay and it is on the way since both my compressors take the same motor. Apparently these have a pivot hinge which is uncommon. No one has that mount. If the motor in it is indeed bad I will have the bracket cut off and find a way to modify it for a standard mount motor.
 

pipsters

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If you're plugging in a 1.9 hp motor to a 120v 15 amp outlet and it's popping it's because the load is so high on initial start. If it isn't popping on 20 amp outlets there is nothing wrong with the motor.

If you are talking 5 hp @ 7 cfm @ 120v that simply isn't possible. 10 years ago motors were rated at their initial start capacity hence why the CFM is so high. My same compressor from Sears was rated at 7.8 CFM @ 90 psi and 5 hp yet now, using the same motor, it's rated at 5.8 CFM @ 1.8 hp.
 

csp

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Surplus Center is also a good source for affordable electric motors. www.surpluscenter.com

I need to get a new motor for one of my compressors also unfortunately. It fell over and cracked one of the cast iron end caps, rendering the motor useless. It's old enough that a replacement isn't available.
 

KinzeMech

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Jul 15, 2012
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Copper ain't exactly cheap anymore.

Being generous, and saying there's 10# of copper in that motor, that accounts for another $20.

The pivot mount makes it a special application motor, and they charge that much because they've got you over a barrel.

Something to think about when shopping for compressors. I will think of it next time...

edit: sorry for the thread necromancy...found it via search and didn't see the post date
 
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