Compressor Motor Upgrade Question

[Rescue Wagon]

I have a Puma PK5020VP that is a 2-HP and rated for 5 cfm @ 90 psi. After some research it looks like the PUMA PK6060V which is a 3-HP and rated for 12 cfm @ 90 psi has the same pump. So, the question is could I swap the 2-HP motor for the 3-HP motor and move up to 12 cfm @ 90 psi?

Thanks.

 

[mikegt4]

There is most likely a difference in pump speed, the 3hp motor has more power to spin the pump faster under load. A search of the web will probably get you the RPM used for each pump, use the appropriate pulleys.

 

[Rescue Wagon]

I looked and if the websites I found are correct here is the rpms for each:

PK6060V

Pump Rpms: 1450
Motor Rpms: 3450

PK5020VP

Pump Rpms: 1100
Motor Rpms: 3450

 

[pattenp]

Motor and speed plays a big part but I don't think you will see an increase from 5 to 12 with just a motor change. I think the tank size and other parts and pieces play a part. You really need to make sure it's worth the cost and effort to put on a 3HP motor and do a pulley change for what ever cfm increase you may get.

 

[Rescue Wagon]

That is why I was hoping someone on GJ could help that is a little smart on compressors than I am.

 

[Cyberbear]

The tank size will only affect how long it takes to fill and not the motor size, RPMs being what they are. The larger motor will pull more amps and I prefer to use #10 awg copper wire on a single phase 220 volt system. Try to get a better than 50% duty cycle on the motor, if possible. Also, make sure to confirm motor rotation before purchase. Otherwise I see no apparent problems.

 

[Miss_Sissy]

Try to get a better than 50% duty cycle on the motor, if possible. Also, make sure to confirm motor rotation before purchase. Otherwise I see no apparent problems.

I see many apparent problems, including the likelihood that he would destroy his pump and/or not achieve a significant improvement in performance.

1. The math does not work using the numbers supplied.

1450 RPMs is 32% higher than 1100 RPMs.
12 CFM is 140% higher than 5 CFMs.
You don't get a 140% increase in CFMs by running the same pump 32% faster.
​

Since the math does not work, it means that the pumps cannot be the same.

2. Compressing air makes lots of heat. His pump probably doesn't have the cooling margin to support that kind of heat production.

3. The pump is almost certainly not capable of turning fast enough to flow 240% of its current airflow (12 CFM vs 5 CFM). Piston pumps, like piston engines, have "red lines" for RPMs.

I have a Puma PK5020VP that is a 2-HP and rated for 5 cfm @ 90 psi. After some research it looks like the PUMA PK6060V which is a 3-HP and rated for 12 cfm @ 90 psi has the same pump.

I'm not sure what you found, but looking at the parts diagrams for each reveal numerous part number differences (pistons, cylinders, crankcases).

I looked and if the websites I found are correct here is the rpms for each...

I just bought a PK6060V and I can tell you that the 1450 rpm pump speed you quoted is wrong (it probably came from the Northern Tool website). Steve at Puma Air and Steve at Air Compressors Direct (two different Steves) stated that the pump rpm spec on the Northern Tool website is wrong. It's actually 980 RPM. You can see the correct specs here:

http://www.aircompressorsdirect.com/Puma-PK6060V-Air-Compressor/p591.html

Give a call to Puma Air at 901-744-7979 and talk to tech support. I was very impressed with Steve in tech support. He was genuinely enthusiastic and happy to spend time talking compressors, design trade-offs, upgrades, etc.

Realistically, your best, most economical approach is probably to sell your PK5020VP and buy a PK6060V from Northern Tool. They have them on sale for $500 and they will be down to $480 for Black Friday.

 

[Rescue Wagon]

@ Fred - Thanks so much for the info. The numbers seemed a little off, but I couldn't find a reliable source and why I came here to ask. For the price I think you are correct that upgrading to the PK6060V is the best option and should be a huge improvement over my PK5020VP.

If you don't mind me asking what kind of plug comes on the PK6060V or do I just need to hard wire it to a disconnect?

Thanks again for your input.

 

[Miss_Sissy]

For the price I think you are correct that upgrading to the PK6060V is the best option and should be a huge improvement over my PK5020VP.

I think so. You'll be able to sell your nice, albeit smaller, compressor and recoup much of the cost for the upgrade. When you look at the price for new 3HP compressor motors that are decent quality, it's prohibitive (you and I don't get them at the prices that Puma, Campbell Hausfeld, and DeWalt do).

If you don't mind me asking what kind of plug comes on the PK6060V or do I just need to hard wire it to a disconnect?

The PK6060V does not have a pre-installed power cord or plug. I think that most people probably wire it directly to a breaker.

But I went with a 30A, 240VAC electric clothes dryer plug and outlet. They are economical, mechanically robust, and can handle the startup surge, which is higher than the running current. It's a tight squeeze to get a dryer cord under the pressure switch cover and you might have to terminate the leads at just the right lengths (I did), but it can be done.

Thanks again for your input.

Thanks for the nice reply after I went into engineer mode on you and probably skimped on the social niceties.

 

[Bob C]

its 10.6@90 on your 60 gallon. Take the motor and pulley from the 60. Bolt it on your 20. Enjoy.

 

[Miss_Sissy]

its "10.6@90" on your 60 gallon.

Not according to the manufacturer. Puma advertises that the Puma PK6060V puts out 11.3CFM at 90psi. See:
http://www.aircompressorsdirect.com/manuals/pumapk6560vcatalogpage_oct2014.pdf.

Not that it's relevant, since the PK6060V has a higher displacement pump than the one on the PK5020VP.

Take the motor and pulley from the 60. Bolt it on your 20. Enjoy.

Are you willing to reimburse his several hundred dollars of costs after your advice results in him 'enjoying' about 85% of airflow than he started with?

I did the research necessary to give Rescue Wagon sound advice:

• The PK5020VP turns its pump at 1150RPM.
• The PK6060V turns its larger displacement pump at 980RPM.
• The PK5020VP and PK6060V use the same diameter pump pulley (Puma part number 3PBF-105A124).
• The motors on both units spin at 3450RPM.
• The motor pulley on the PK6060V has to be smaller in order to turn its pump slower.

Putting the 3HP motor and the smaller motor pulley from the PK6060V onto a PK5020VP would slow the PK5020VP pump down from 1150RPM to 980RPM, lowering the output from 5.0 CFM at 90psi to about 4.3 CFM at 90psi.

 

[Tronyadorable]

Call steve
901-744-7979

 

[Miss_Sissy]

Call steve
901-744-7979

Agreed, Steve at Puma Air.

I already spoke to him about this -- to make sure that I was giving sound advice. He'll tell Rescue Wagon the same thing I did: Sell the PK5020VP and buy a PK6060V. You can't get 11+ CFM out of the 5 CFM pump used on the PK5020VP. I bet that the 5020 would go for $400 if it's in nice shape. Add $100 to that and you can pay for the 6060 brand new.

 

[Rescue Wagon]

Thanks again for all the info. Who new it would be this hard to get a few more cfms?

 

[Montosi82]

I've go my eye on the puma 6060v also. Just an FYI I found northerns shipping to be around $230 dollars for me in massachusetts. So yes 480 plus shipping is 710 plus tax. I found it on Home Depots website with free delivery to the store for around 640. Don't know your shipping costs or availability to pick up and unload a compressor of this size but savings 70 bucks might be worth a ride to Home Depot. Good luck and post up a review. Happy thanksgiving!

 

[Miss_Sissy]

I've go my eye on the puma 6060v also. Just an FYI I found northerns shipping to be around $230 dollars for me in massachusetts.

Is it just me, or do you also find it odd that a store called "Northern Tool" has this mix of store locations?

Good luck and post up a review.

In the interest of not starting too many new threads, I'll give a brief review of my new Puma Air PK6060V here.

"Executive" Summary:
The PK6060V seems to be built for the long haul. It runs slower than many competing units and is on the lower side of tank pressures with its 130PSI cutoff rather than the 150-155 psi cutoff of some competing units. Because it's turning the V-twin pump at a nice, slow 980 RPM, it has a quiet, pleasant, somewhat relaxed sound when running -- unlike higher RPM parallel twin pumps. Things the like factory-installed ball-valves on the output and drain and generally high quality components throughout means that you won't be nickel-and-dimed as you replace, upgrade, or add

Pros:

• Cast iron V-twin pump with cast iron heads. This leads to quiet running, long life, and more even cooling due to the cylinders being exposed all of the way around (uneven cooling of cylinders can lead to shortened pump life and more blow-by as the cylinder go out of round due to uneven expansion of the metal).
• Long, copper air lines with extensive fins for cooling the air on the way to the tank.
• Top quality 1/2" ball valve on the compressor output -- not the empty, threaded hole in the tank that is more typical.
• Ball valve drain with decent access.
• Very good U.S. Motors brand electric motor.
• SP-204 pressure switch. It's not a $100 Hubbell, but it's a decent switch with contacts that are known to hold up to a 3hp+ electric motor.
• Decent air filters and intake mufflers.
• Sight glass for oil level and condition (clarity).
• Steel-framed, welded, belt guard with low-restriction mesh.

Cons:

• Had to add a bit of car door edge guard to the bottom of the belt guard to eliminate a minor. Just took 5 minutes.
• Tank pressure gauge

• - These are all disposable items on compressors in this size/price class. I don't trust any of them including the one on the PK6060V.
• - Not liquid-filled, so the vibration makes the needle jump around. I also have concerns about the affect on lifespan and long-term accuracy.
• - It is bottom mount variety that is screwed into a side port of the air pressure switch. That means that it's rotated 90 degrees. Works fine, but kinda wonky looking.
• - That's all easily fixed with a 1/4" NPT elbow, a brass ******, and a decent, liquid-filled gauge (which you can get for under $20).

Hope that is of some help to those considering the Puma Air PK6060V

 

[Bob C]

I have a Puma PK5020VP that is a 2-HP and rated for 5 cfm @ 90 psi. After some research it looks like the PUMA PK6060V which is a 3-HP and rated for 12 cfm @ 90 psi has the same pump. So, the question is could I swap the 2-HP motor for the 3-HP motor and move up to 12 cfm @ 90 psi?
Thanks.

Yes. Motor and pulley.

 

[Miss_Sissy]

Yes. Motor and pulley.

As I said before, that is incorrect. I've already spoken to Puma Air tech support about this.

• The PK5020VP turns its pump at 1150RPM.
• The PK6060V turns its larger displacement pump at 980RPM.
• The PK5020VP and PK6060V use the same pump pulley (Puma part number 3PBF-105A124).
• The motors on both units spin at 3450RPM.
• The motor pulley on the PK6060V has to be smaller in order to turn its pump slower.

Putting the 3HP motor and the smaller motor pulley from the PK6060V onto a PK5020VP would slow the PK5020VP pump down from 1150RPM to 980RPM, lowering the output from 5.0 CFM at 90psi to approximately 4.3 CFM at 90psi.