10hp air compressor....how to power it.

[the old grind]

I'm guessing that the 29cfm model is rated there at higher than 125psi, so my thought is that the smaller motor would suffice with that shut-off setting. RPCs aren't as flexible as VFDs, and Phase Perfect, while versatile, is to pricey for most of us.

PSC (permanent split capacitor) motors are often rated 'compressor' duty. Which means their hp rating isn't for continuous running. A 3hp is then 2hp if run continuouslyw/o o'heating, but can be overloaded and draw more current late & short in the pumping cycle, when pressure and amp draw peak. 5 hp 'compressor duty' is more like 3 hp continuous. If we load and dyno test these at their 'rated' hp long enough they will o'heat and should shut down by internal o'load sensor.

A continuous 5hp motor (preferably TEFC vs ODP, and CSIR or cap start induction run will last longer) The ODP 5hp HFT 1-PH that draws 15a. is a 5/3 compressor motor, the Baldor that draws 24a. is a real 5hp/

CSCR (cap start cap run) are vulnerable to either (say 180-210 mfd start, 30 mfd run in 5hp) cap 'deforming' if it sits long enough. We 'reform' any caps by charging them at lower voltages and or lower current to reattach gel-like chemicals to the foil layers within. Loading-up and starting a shelf queen can pop 'em without an hour or two of no load running.

I wonder if a 7.5hp, with that small tank and low pressure will run all your gear, even with a lighter duty (less costly) ODP CSCR motor. Your load doesn't seem to me to justify more power within those confines.

As Mendonsy says thumbsup look on ebay or CL for used motors, and good luck having much selection in 1-PH >5hp. I just 'searched' Amazon and ebay .. guess what "7.5 hp single phase" in the search box gets you 1/2 hp - >10 hp and 3 PH as well on any site, so don't count on the quickest 'find'.
If new:
New Leeson Electric Motor 7.5hp 1ph 23Volt 184T 345 rpm 1 1/8 shaft - 13244 - Compressor motor by Leeson - - Amazon.com
7.5HP Farm Duty Single Phase Motor 1 3/8" Shaft, 23/46V, 213T, 345 RPM, TEFC | eBay

Tell you what, if you rue my advice here down the road, I could drive down and buy the one you wish you hadn't. <Meanwhile, if you have a 1-PH 5 hp to try, I'd gear it like you would the 7.5/29cfm (>90% the rpm of it), and see what amps it draws up to the 125 psi shut-off. t o g

 

[kenmac]

I don't know what all you use air for, but My 7.5 hp compressor produces 25 CFM @100 and I have never run out of air sand blasting / painting , running grinders, etc,.with it.
When sand blasting, Compressor will kick on, but will recover and shut off.

 

[oldnslo]

LD1
Any semi abandoned dairy farms or upright stave silos in your area? If yes the silo unloaded motor is probably a 5 or 7 1/2 Hp motor Our Milking vacuum pump was also 7 1/2 HP. Possibly grain dryer motors also could be 5 to 10hp

Just throwing out some possible sources for used motor

 

[LD1]

Old grind.....nope. 125psi max for all configurations of pump.

Looking at 6 potential motors....
Baldor L3711t or L1511t
Leeson 140681 or 140685
Marathon L106 or L225

Have seen prices for all between $750-$1100. Marathon being cheapest...leeson a tad more....and baldor the most.

I am.gonna call around tomorrow to some motor shops. But not holding my breath for a 10hp single phase.

 

[the old grind]

14644. LEESON 14644 1HP MOTOR C215K34DK2A
Leeson 10 hp ODP 3465 rpm (2 pole, mounting flange says 'pump' use type, 47 FLA, 57a at stall) 'Inverter-type' is the most HD, to not o'heat when used with PWM VFDs

1HP Farm Duty Single Phase Motor 1 3/8" Shaft, 23/46V, 215T,1725 RPM,TEFC | eBay
10 hp TEFC (w/fan bell) 1725 rpm (4 pole)

rpm is somewhat moot, because we gear a pump input shaft to the rpm spec'd by mfgr. Keep motor leads short and 'fat'.

Lots out there if you look. FL amp draw is typically only under full load, not 95% of the time, as in when you don't need all 40cfm.

For that I give a lot of creedence to those who are getting plenty of air w/o going to full rated hp.

Sky is the limit until you spring the $$. Tough one with so many choices, eh? (that always hold me back. :laughing keep looking. Happy Easter!

 

[LD1]

14644. LEESON 14644 1HP MOTOR C215K34DK2A
Leeson 10 hp ODP 3465 rpm (2 pole, mounting flange says 'pump' use type, 47 FLA, 57a at stall) 'Inverter-type' is the most HD, to not o'heat when used with PWM VFDs

1HP Farm Duty Single Phase Motor 1 3/8" Shaft, 23/46V, 215T,1725 RPM,TEFC | eBay
10 hp TEFC (w/fan bell) 1725 rpm (4 pole)

rpm is somewhat moot, because we gear a pump input shaft to the rpm spec'd by mfgr. Keep motor leads short and 'fat'.

Lots out there if you look. FL amp draw is typically only under full load, not 95% of the time, as in when you don't need all 40cfm.

For that I give a lot of creedence to those who are getting plenty of air w/o going to full rated hp.

Sky is the limit until you spring the $$. Tough one with so many choices, eh? (that always hold me back. :laughing keep looking. Happy Easter!

That brings up a good point there.

I was filtering searches to limit to 213t/215t frame motors since that is what it has.

I guess I just figured since it was a much more "standard" frame size, that the JM and similar type motors with different shaft diameters, or extended shafts would be more expensive. Guess not.

I can get a pulley bushing to fit a different size shaft and cut the extra length off to save about half on a motor.

Kinda odd that the leeson you link....140644.....is only $435....and the similar 140681 with a more standard 215t mount is $955 from the same place.

And not sure I have ever heard the term inverter duty when talking about single phase motors either?

 

[the old grind]

... not sure I have ever heard the term inverter duty when talking about single phase motors either?

It kinda doesn't make sense, but I have/use a HFT 'Router Speed Control', which is PWM like 3 PH VFD's are. I made a jumper w/50a spaded FW bridge rectifier to use with 130v DC treadmill motor for my Cinci T&C grinder vs OEM 440v 3PH. Yeah, it growls at low rpm that I wouldn't use, but does give me good speeds for both 3 1/2" & 5" bonded wheels.

Anyway, the speeder doesn't just work with routers. I use it to mix protein drinks and can slow my H-B shake maker on the 'hi' setting to reduce foaming in my blend. So, these instances are using PWM to vary speeds of motors that (minus slip) basically lock into the 60Hz of our supply.

As with VFDs then, it seems there are 'ID' motors to handle the strains of their non-typical loads/speeds. We can generate a lot of torque with PWM at lower rpm (lathe, mill) but TEFCs can run warm when the fan slows. If we can't prove it's more than marketing buzz, 'ID' seems to connote 'rough service' and/or continuous use. (large/muni water systems use PWM VFDs & 'Inverter Rated' motors a lot)

Do your best to balance any pulleys and be sure they run true. HFTs digital tach works for me to reverse-calculate driven pulley rpm, blade fpm, etc. Here I brought a wood saw's blade down from >2400 to <600 fpm for metals by adding a jack-shaft, and calculating from 14" wheels' rpm.