Replacement Speedaire compressor motor

[wadeclinton]

New member here. I have a question for the group regarding replacing an electric motor on a Speedaire air compressor. I was able to score a working compressor pump and two 80 gallon tanks for 300$

I knew the electric motor was bad when I bought the lot. I later confirmed this with the assistance of a friend. He's a maintenance mechanic for a local school district, and found a dead short through ohm'ing the motor.
Grainger is the retailer of these compressors and after digging through that site I found my model is out of production, but there is a similar one. https://www.grainger.com/product/SPEEDAIRE-5-HP-35WC40
I also found that USMotors does not sell replacement motors. Grainger suggests a motor similar to this: http://www.globalindustrial.com/p/motors/ac-motors-definite-purpose/compressor-duty-motors/motor-184-dp-1ph-3450rpm-c184k34db8aa Grainger sells a7HP motor but its almost 1000$ I used this other one as a reference and because Global Industry occasionally offers free shipping. eBay also has several offerings that are priced about 500$and consistently offer free shipping.
Dimensional the 7HP motor is a monster compared to what I have on the unit currently.

Here is a data tag of what I have

I am wondering if the bad motor I have is actually a 7HP motor. If its not a true 7HP then I may have found an alternative.
At the Local Tractor supply i found this:

The question for the group is will a 6HP motor work for what i'm trying to accomplish? Should I bite the bullet and order up the big 7HP? Will I waste time and money with the 300$ TSC motor when it craps out in 6 months? The TSC motor has my eye because its 200$ cheaper than anything else I've found, its local so no shipping. But it is 1 hp less than Grainger recommends, assuming the OEM motor is truly 7HP.

 

[CNGsaves]

OP . . . you'll need to post MORE INFO on the SpeedAire pump to have GJ guru's chime in. Like Model #, size, etc. Post up more PIC's of the compressor head itself, along with tank tag which may provide some useful information.

Are you trying to make 2 free standing 80 gal complete compressors, or just one ??

For $299 that Marathon 6 HP motor is good price. Other brands to consider are Baldor, AO Smith, & Leeson so do some "window shopping" on Ebay and CL for comparison purposes.

 

[jallyn]

I would buy the $300 motor and set it up with your existing pump, pulleys, etc. If it consistently trips the "Manual Reset Thermal Protection" after running a few minutes then change the motor pulley to one slightly smaller (20% smaller in diameter). This will slow down the compressor enough so that the motor doesn't run overloaded.

Or if you are in a hurry just spring for the 7.5 HP. You already got such a good deal on the compressor might as well make it right.

 

[CNGsaves]

Here is 7.5 HP Baldor single phase in Detroit, MI for $350 . . . .
. . .
. . . . . . any GJer's in that area who could help out our OP to check out ??
. . .
http://detroit.craigslist.org/mcb/for/5461302352.html
. .
= = = = = = = = = = = = = = = = =
. .
Here's another 7.5 HP Baldor single phase but says it's "not self cooling" & needs fan ?
Listed at $ 285 in Woodsboro, MD

http://frederick.craigslist.org/for/5423522610.html

 

[stonesfan68]

Go to Grainger's site and type in G84560. It will bring up item # 4FN97. That's the motor that you need for the compressor. According to the motor data plate and Grainger data you need a 7.5 HP ODP motor, 184T frame, 230V/1/60, 3500 RPM, capacitor start. Given those parameters you can search for another brand/supplier. The Grainger price on the motor is $641, but my company has an account that includes a discount. The motor at Global Industrial that you find will work for this application.

As has been pointed out, you can use the TS motor, but get with a local motor or drive supply shop and get a smaller pulley and longer v-belt to slow the compressor pump down so as to not burn up the "6HP" motor.

You can go with a more industrial, 1800 RPM full-voltage start motor, but then you'll need a new motor pulley, belt, pressure switch and magnetic motor starter, so it might be cheaper to stick with the type of motor that is currently on the machine.

You don't indicate otherwise, but if this machine will be for a home shop then you should have no trouble with the compressor by connecting the two tanks and having the machine fill them simultaneously.


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[jallyn]

Well the OP nameplate said frame 184. Frame 184T has a larger diameter shaft than frame 184, so be careful of the difference. Frame 184T could work, but the bore of the motor pulley would have to be changed to match the larger motor shaft.

 

[ngonerogwu]

I have that compressor.

Campbell hausfeld made it for speedaire. It's an actual 7.5hp motor.

 

[wadeclinton]

OP . . . you'll need to post MORE INFO on the SpeedAire pump to have GJ guru's chime in. Like Model #, size, etc. Post up more PIC's of the compressor head itself, along with tank tag which may provide some useful information.

Are you trying to make 2 free standing 80 gal complete compressors, or just one ?

CNGsaves, I am going to make the two tanks into one. One tank will have the motor and pump. The second tank will be for added storage. Why? why not the deal was pretty good.

Here are pictures that may illustrate more fully what I'm working with:

The compressor will be used for an aggressive home mechanic/fabricator. I like to run air tools whenever possible and hate waiting for air to build up. I occasionally need to air carbon gouge and eventually will add a plasma cutter to the mix.

 

[wadeclinton]

As has been pointed out, you can use the TS motor, but get with a local motor or drive supply shop and get a smaller pulley and longer v-belt to slow the compressor pump down so as to not burn up the "6HP" motor.

Could you elaborate on this more? I suspect that I'll be diminishing the capacity of the pump in terms of CFM output and a longer fill time. Would there be any other effects beyond that?

 

[wadeclinton]

Here is 7.5 HP Baldor single phase in Detroit, MI for $350 . . . .
. . .
. . . . . . any GJer's in that area who could help out our OP to check out ??
. . .
http://detroit.craigslist.org/mcb/for/5461302352.html
. .
= = = = = = = = = = = = = = = = =
. .
Here's another 7.5 HP Baldor single phase but says it's "not self cooling" & needs fan ?
Listed at $ 285 in Woodsboro, MD

http://frederick.craigslist.org/for/5423522610.html

Thanks for the Craigslist links. I've not found anything on my local searches. I think the shipping to CA would be a deal breaker.

 

[bronc3buster842001]

I used that same motor from TSC on my compressor.. Been working fine.. Takes a minute to get going when its cold.. Been holding up for a couple years now..

120 gal tank with knockoff Saylor Beall 705 pump

 

[CNGsaves]

OP . . . . . that is Beast of a pump at 25 CFM !!!

Since you're planning on coupling the two 80 gal tanks together for . .
160 gal total storage at 175 psi . . . . . DAYUUUUM !!!!! . . .
I'd sure stick with 7.5 HP motor and not degrade to 6 HP.

Don't rule out the Baldor motor in Detroit until we hear from GJer's in that area. You could ship from Fastenal store to Fastenal store for lower cost.

Anyone in Detroit to check out Baldor motor for the OP ??

 

[wadeclinton]

OP . . . . . that is Beast of a pump at 25 CFM !!!

Since you're planning on coupling the two 80 gal tanks together for . .
160 gal total storage at 175 psi . . . . . DAYUUUUM !!!!! . . .
I'd sure stick with 7.5 HP motor and not degrade to 6 HP.

Copy, do not go with the 6hp option.

And yea. I did the quick math when I met up with the seller and decided quickly the 300$ price was well worth it. The guy that had it was running a screen printing shop. The unit was in service for 2-3 years before the motor died. The bare tank was his first unit running the shop, and it went 10 years before the air pump died. He'd decided to replace the whole unit with a Quincy rather than order in a new motor.

Lucky me.

Thanks to all for the input.

 

[stonesfan68]

Could you elaborate on this more? I suspect that I'll be diminishing the capacity of the pump in terms of CFM output and a longer fill time. Would there be any other effects beyond that?

You are correct, the pump will run slower and make less air. The fill times will be longer. The required horsepower will also go down so as to not overload the 6HP motor.

For light industrial use as you've described I wouldn't worry a bit about using both tanks with the single compressor. Connect the two tanks together and use a tee fitting for the discharge to the compressed air header. Put a pressure regulator on the tee fitting, connect that to the air distribution system and you'll have plenty of 150-175 psig air stored for use at 90-100 psig at the tool.

By the way, great deal on these compressors.


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[wadeclinton]

I thought I should update the thread. I found a motor. I got a brand new Leeson 7.5 hp through eBay. 420$ shipped. The motor arrived Wednesday. I got everything mounted, wired, tested, and plumbed today.

Pictures for the group.

Data plate



Mounting it up. FYI the 7.5 hp motors are heavy.



Pulling the pulley from the old motor



Belt tensioning





The first pressure run. It took about 2-3 min to go from 0 psi to the cut out at 175 psi. Cut in is about 100 psi. Cut in to cut out is less than a minute.

https://vimeo.com/161423791

There is a slight rattle. It's the cover plate for the heater and connection box. I'll need to tighten that up. My OCD can't stand it.

I still need to connect the tanks. 3' or so of braided HP hose should do nicely. I'll have to get that made when I run into Fresno next week. I also need bolt the units to the floor. I'll have to grab isolators and anchors while I'm at it.

 

[Roberts210]

Outstanding job!! You can definitely run some serious air tools now.

 

[wadeclinton]

Keeping the thread alive. Today I borrowed a hammer drill and got the tanks anchored to the floor. The isolation pads were sourced through an eBay seller. I got 8 for 30$ shipped. The anchors are 1/2"x5", looking back i probably could have used 3" or 4" anchors. I also shortened my extension cord and used up some sheathing I had left over from another project. The sheathing going from the starter box to the motor Is bothering my OCD. I'll get that replaced soon. I should have a hose made up for connecting the tanks tomorrow. Then It'll be time to start saving for reels, filters, and other goodies.

Pictures

 

[MacMcMacmac]

Glad you got a proper motor. That first one you showed had a duty cycle. which says to me it's working extra hard to produce 6hp (i.e. it's really a 5hp motor, if that). The Leeson clearly states it's a continuous duty motor, which, if you are going to be blasting or air gouging, is probably necessary.

 

[redmondjp]

Wow! Impressive setup. I question how the manufacturer got away with only one V-belt (unless it is a larger size one).

All of my 5+ HP compressors have dual V-belts on them.

 

[jallyn]

Very nice setup. Jealous.

 

[ScottsGT]

I have a SpeedAir with the same tank, just a smaller head. 5hp, and I too bought it with a bad motor. Grainger had what I needed.

 

[wadeclinton]

Thank you for the compliments. To answer a few questions. I don't know why speedaire used motors with duty cycles. Possibly to keep the units cost down? The single belt is a mystery as well, most everything I've seen is dual as well. My belt looks to be either 1/2" or 5/8", nothing spectacular. I didn't bother changing it out either. It's in good shape.

I did get the tanks plumbed together tonight though. It took a bit to get both tanks filled back up. Probably 5 or so minutes. I didn't time it to be certain.

 

[wadeclinton]

https://vimeo.com/164202196

A video of the system fully operational.

I still need to source a reel and filters. But for now it will do.

The hose was provided by a local hydraulic shop. 90$ out the door. It's rated to some 300 degrees and 3200 psi. I used my point and shoot temp gun and took some readings. First tank inlet read 190 degrees. First tank read 80-90 degrees. First tank outlet 75 degrees. Coupler hose 70 degrees. Second tank 70 degrees. I think I will be fine.

 

[higglewiggles]

Reviving an old thread- Wade, were you able to utilize your existing pulley? I have the same G84560 motor and looking for a new motor. Thank you!

 

[Shoreline_]

Reviving an old thread- Wade, were you able to utilize your existing pulley? I have the same G84560 motor and looking for a new motor. Thank you!

As long as the frame is the same, the pulley will fit. If your rpm is twice as fast as your old one then you will need a pulley half the diameter.

 

[higglewiggles]

As long as the frame is the same, the pulley will fit. If your rpm is twice as fast as your old one then you will need a pulley half the diameter.

I looked up a NEMA electric motor chart from Baldor, and it’s showing a 184 is a 7/8” shaft, whereas a 184T is a 1 1/8” shaft. Link to the Baldor/NEMA page is below, column U. I suppose I can try to find another pulley if it’s not a direct replacement, but it appears OP just pulled their pulley off and threw it on the new motor… would make life a heck of a lot easier. For reference, the motor RPM is nearly identical between the one OP used and the motors we are replacing.

https://www.baldor.com/Shared/pdf/nema_chart_04.pdf

 

[Shoreline_]

I looked up a NEMA electric motor chart from Baldor, and it’s showing a 184 is a 7/8” shaft, whereas a 184T is a 1 1/8” shaft. Link to the Baldor/NEMA page is below, column U. I suppose I can try to find another pulley if it’s not a direct replacement, but it appears OP just pulled their pulley off and threw it on the new motor… would make life a heck of a lot easier. For reference, the motor RPM is nearly identical between the one OP used and the motors we are replacing.

https://www.baldor.com/Shared/pdf/nema_chart_04.pdf

What's the point of your post? You didn't add any additional information. Like I said as long as the frame matches (all the characters) and the rpm is the same you can use the old pulley. That's called a NEMA code. If the rpm is double the speed on the new motor you need a pulley half the diameter. It's basic physics. If the shaft is smaller well then I guess you need a different bore too it's not rocket science.

 

[higglewiggles]

What's the point of your post? You didn't add any additional information. Like I said as long as the frame matches (all the characters) and the rpm is the same you can use the old pulley. That's called a NEMA code. If the rpm is double the speed on the new motor you need a pulley half the diameter. It's basic physics. If the shaft is smaller well then I guess you need a different bore too it's not rocket science.

The additional information is literally a chart with each motor size charted out… just because the frame matches, doesn’t mean anything else does and that is literally taken directly off the chart. The OP and I are replacing the same motor. The simple question to the OP who purchased this motor was is it a direct replacement, because according to the chart they are different. No need to get all worked up over something you don’t have any skin in. I don’t care about the speed of the motor, my only question is in the diameter of the shaft that the pulley is on. Relax, my friend. Its a simple question for the OP.

 

[Bert_]

Frame size defines shaft size and location.

 

[The Cobbler]

No one needs to get their knickers in a Knot when people are trying to help. and since the OP has not been online for over 5 yrs, don't hold your breath waiting for a reply...