replacement for Husky 7.5 compressor motor

[rnscustom]

Was a baldor motor , original to the compressor . Had 2 blown capacitors and a cooked contact when I bought it . Replaced with advice of rebuilder and cooked again . Not sure where the compressor was bought new . Again to me for time and money my guy was correct get a new one and move along .

 

[mm08822]

The point that is being missed in this thread is that although motors are designed to run at +/- 10% of nameplate voltage, however, prolonged/continuous running at these threshold voltages greatly shortens the life of the motor due to heat. Intermittent voltage variations throughout the day is expected and is the intended reason to build in the voltage range for motors. Every 10 degrees C total temp rise will decrease the winding insulation life by 50%.

Refer to the ECMWeb article in the above post and read it in full.

RNSCustom states the original motor was a 200V nameplate. Then running it at 220V (I’ll assume that is your measured applied voltage at the motor for whatever reasons – utility, wire size, bad cons, whatever…), you were at the +10% limit (continuously I assume) and therefore well on the way to achieving only 50% motor life.
Now putting a 230V motor onto a delivered 220v, would put you running in the -5% range or less depending on actual motor load applied. Even with full load applied to the motor, this is much better than being out at +10%.

As for the OP, since there is no prior data as to the operating point of the motor(s), it is a little bit of a guessing game as to where the problem is.
Maybe moving up to a 5HP will solve your problem. You however now have an entire new set of things to consider:
Wire size, cb size, OL heater size, or Pressure switch contact ratings and voltage drop on startup. If startup voltage does drop off with the 5 Hp, your contactor may drop out on low voltage. Running a 5HP motor lightly loaded is not efficient either and that will cost you more $ in lower motor efficiency.
The 3 HP motor may still be the better choice. Really can’t say for certain as none of the details before failure are available.

For either size motor you choose, using Aceman’s startup sequence will give you an operating point – immediately and for future reference.

Motor efficiencies are improving all the time so going by motor FLA’s is not a clear cut indicator of BS or not. A motor with a stated HP (not “SPL”) will deliver the rated HP and with the SF stated.
The Leeson motor you found clearly indicates it is 3HP continuous and 5HP at Torque Breakdown (read the fine print). 5HP sounds great, but that liquidation website is purposely misleading the buyer. Breakdown torque is not an operating point that you want to be ever running in or near.

 

[rnscustom]

That was exactly what I was pointing out ,not that the motor wouldn't work but spending money to repair it would be a waste . So better to start out with a motor rated where I should be . Also may or may not have anything to do with the op issue but it was a place to post compressor motor issues . Could help someone that keeps buying the same nameplate but keeps failing every few years .

 

[manwithtools]

The point that is being missed in this thread is that although motors are designed to run at +/- 10% of nameplate voltage, however, prolonged/continuous running at these threshold voltages greatly shortens the life of the motor due to heat. Intermittent voltage variations throughout the day is expected and is the intended reason to build in the voltage range for motors. Every 10 degrees C total temp rise will decrease the winding insulation life by 50%.

Refer to the Motor manufacturers web site and read it in full.

Fixed it for you.

Intermittent voltage variations throughout the day is not the reason for the extended voltage range, read my post #13. It's what's called "utilization voltage".

The frequent starts of a compressor are probably more detrimental to the motor life than a reduced operating voltage. Even if the reduced voltage did reduce the motor life significantly for an air compressor, most users would not notice it in their lifetimes. 10,000 hours vs 20,000 hours, probably not a big deal to any of us. Calculate how many shop hours that equates to. Other factors such as humidity, chemicals, dust, etc. will likely have a greater effect on motor longevity.

Some good reading from Leeson:

http://www.leeson.com/TechnicalInformation/hottopic.html

And US Motors:
http://www.usmotors.com/TechDocs/ProFacts/Voltage-Frequency-Variation

Modern motors of good quality will feel hot, very, very hot. Outer housing temperatures of 150-200 degrees are not uncommon. The motors are designed to work at those temperatures.

We have sufficiently derailed the OP's post at this point, so I'll bow out. It's fair to say the if he increases the size of the motor it will likely solve his friends problem. To the point, modern motors are more efficient so the devil is in the details.

As a matter of fact, if you read his post #8, I think he already understands more than most of us responding this thread.

RNSCustom's problem was already solved, so we can disarm that conversation too.

Cheers!

 

[toplessHO]

The point that is being missed in this thread is that although motors are designed to run at +/- 10% of nameplate voltage, however, prolonged/continuous running at these threshold voltages greatly shortens the life of the motor due to heat. Intermittent voltage variations throughout the day is expected and is the intended reason to build in the voltage range for motors. Every 10 degrees C total temp rise will decrease the winding insulation life by 50%.

Refer to the ECMWeb article in the above post and read it in full.

RNSCustom states the original motor was a 200V nameplate. Then running it at 220V (I’ll assume that is your measured applied voltage at the motor for whatever reasons – utility, wire size, bad cons, whatever…), you were at the +10% limit (continuously I assume) and therefore well on the way to achieving only 50% motor life.
Now putting a 230V motor onto a delivered 220v, would put you running in the -5% range or less depending on actual motor load applied. Even with full load applied to the motor, this is much better than being out at +10%.

As for the OP, since there is no prior data as to the operating point of the motor(s), it is a little bit of a guessing game as to where the problem is.
Maybe moving up to a 5HP will solve your problem. You however now have an entire new set of things to consider:
Wire size, cb size, OL heater size, or Pressure switch contact ratings and voltage drop on startup. If startup voltage does drop off with the 5 Hp, your contactor may drop out on low voltage. Running a 5HP motor lightly loaded is not efficient either and that will cost you more $ in lower motor efficiency.
The 3 HP motor may still be the better choice. Really can’t say for certain as none of the details before failure are available.

For either size motor you choose, using Aceman’s startup sequence will give you an operating point – immediately and for future reference.

Motor efficiencies are improving all the time so going by motor FLA’s is not a clear cut indicator of BS or not. A motor with a stated HP (not “SPL”) will deliver the rated HP and with the SF stated.
The Leeson motor you found clearly indicates it is 3HP continuous and 5HP at Torque Breakdown (read the fine print). 5HP sounds great, but that liquidation website is purposely misleading the buyer. Breakdown torque is not an operating point that you want to be ever running in or near.

maybe you missed my post prior to posting the Surplus Center link that its BS
that they are selling 3HP motors and calling them 5 HP.

As for all the other stuff to connect this I will install everything needed to make this run properly.
I think Im going to get the 6 HP one at Tractor supply for $299.
It should be loafing and is only $20 more than the 5 HP one (which isnt in stock anyway).

 

[toplessHO]

I called CH today and talked to a tech that was very helpful.
Told them that this thing has gone thru 3 motors,all with sucessive part number and supplier changes.
They asked if last one was a WEG to which I replied yes,price at that time was $241,which coming directly from manufacturer seems way too cheap(most likely for a reason).
Rotation is CCW and its correct to have a 3450 rpm motor.Asked what price is now for replacement and they dont offer the WEG anymore,Replacement is US Motor but made in Mexico.No Shame in a name anymore I guess.AND its now $200 more at $440.

 

[toplessHO]

So my browsing at Tractor supply yielded this:
Ingresoll Rand 80 gal at $1100.
Had 3 of them same model. 2 had Chinese pumps,1 had a pump made in India.
All 3 had US Motors,made in Mexico.
Then they have the nerve to paste a big American flag which says "assembled in USA"

 

[toplessHO]

Was a baldor motor , original to the compressor . Had 2 blown capacitors and a cooked contact when I bought it . Replaced with advice of rebuilder and cooked again . Not sure where the compressor was bought new . Again to me for time and money my guy was correct get a new one and move along .

did you take it to the rebuilder and have him meg the windings to see if theres a problem or did he fix it over the phone by throwing parts at it?

 

[wyliesdiesels]

So my browsing at Tractor supply yielded this:
Ingresoll Rand 80 gal at $1100.
Had 3 of them same model. 2 had Chinese pumps,1 had a pump made in India.
All 3 had US Motors,made in Mexico.
Then they have the nerve to paste a big American flag which says "assembled in USA"

Yeah go buy a different brand...

 

[mm08822]

Fixed it for you.

Actually, you did not, but thanks for the effort. Here is the link that I intended:
http://www.ecmweb.com/design/highs-and-lows-motor-voltage

Intermittent voltage variations throughout the day is not the reason for the extended voltage range, read my post #13. It's what's called "utilization voltage".

I did. What you are referring to is a stable voltage deviating from nominal. Even with that consideration, there are still voltage swings during the day/season from that utilization voltage value. Hence, the "intermittent voltage variations." Aside from this, nowhere do you talk about motor life being affected by the added heat of running a motor at overvoltage. You only speak that it will run within the allowed range. Running at the design voltage is optimum for lower internal motor temps enhancing motor life from that aspect.

The frequent starts of a compressor are probably more detrimental to the motor life than a reduced operating voltage. Even if the reduced voltage did reduce the motor life significantly for an air compressor, most users would not notice it in their lifetimes. 10,000 hours vs 20,000 hours, probably not a big deal to any of us. Calculate how many shop hours that equates to. Other factors such as humidity, chemicals, dust, etc. will likely have a greater effect on motor longevity.

Frequent starts of a motor will generate lots of heat and much more when the core is saturated. You miss the big picture - it is not 10C on the surface but multiples of 10C's internal to the windings that can quickly kill the life of a motor. 30C >>50%>25%>12.5% life.........

Some good reading from Leeson:

http://www.leeson.com/TechnicalInformation/hottopic.html

And US Motors:
http://www.usmotors.com/TechDocs/ProFacts/Voltage-Frequency-Variation

Modern motors of good quality will feel hot, very, very hot. Outer housing temperatures of 150-200 degrees are not uncommon. The motors are designed to work at those temperatures. Outer housing temp is not a reliable measure of winding temp. This is why many motors have thermistors embedded in the windings.

We have sufficiently derailed the OP's post at this point, so I'll bow out. It's fair to say the if he increases the size of the motor it will likely solve his friends problem. Sure and maybe make new problems. There is no root cause identified. To the point, modern motors are more efficient so the devil is in the details.

As a matter of fact, if you read his post #8, I think he already understands more than most of us responding this thread. Maybe. But he assumes RNSCustoms 230v motor (at that time in this thread) could handle 200V. That’s a stretch without having a np in front of you. I would hardly say “most” motors can handle 200V. Some yes, but the world is still filled with a predominance of 115/230 and 115/208-230 motors. You would probably need to request it or specifically order it. No bigee, but not run of the mill.

RNSCustom's problem was already solved, so we can disarm that conversation too. It was solved before he posted. I’m explaining why his 200v motor died prematurely while being fed from the reported 220v. Since most peeps here told him he is FOS for the original motor data he provided there was still a critical aspect that this thread was missing after he updated the motor np voltage to 200v – excess heat reduces motor life. Running consistently at that +10% voltage is a problem. Everybody was so hung on voltage range but missed the big pic of running a motor at its np voltage is preferred and necessary to preserve motor life. Read your post #39.

Cheers!

 

[mm08822]

maybe you missed my post prior to posting the Surplus Center link that its BS
that they are selling 3HP motors and calling them 5 HP.

As for all the other stuff to connect this I will install everything needed to make this run properly.
I think Im going to get the 6 HP one at Tractor supply for $299.
It should be loafing and is only $20 more than the 5 HP one (which isnt in stock anyway).

No, I read your posts. I was telling you that the fine print on the Leeson motor says 3HP not 5HP. FLAs are reasonable for 3HP.
I was originally slamming the Surplus website but they are actually disclosing it (assuming you read the fine print). Leeson's website for this motor uses the "SPL" smoke screen around 5HP and never mentions 3 HP continuous. Also "Load Curve Data Not Available" from Leeson! They are the one to be slammed.

 

[toplessHO]

yep it pretty much has been derailed but all good
was mainly looking for any others that had same compressor to see if they had same issues.
Im getting the 6HP one and moving on. Tech at CH says the pump is no longer serviceable so to take prudence in choosing if we want to replace the motor or not.It says 10,000hrs on the sticker and tech says thats rated life of "bearings".... WOW so much BS going on here about ratings. Compressor is going to a new location. I will feed it with #8 on a 30 amp breaker,contacts are rated at 30A,will up grade the cord feeding motor out of pressure switch,which is now a 14 AWG.

 

[toplessHO]

oh and main service(200A thats 5 yrs old) is only 20 ft away
couldnt be much better than this.

 

[rnscustom]

Since this is your post that got derailed I'll answer your question of did the rebuilder throw parts at it . I'm guilty of throwing parts at it , I followed the KISS rule , saw two bad capacitors and I called them for parts pickup , asked a few questions while I was there ( saw the giant stack needing repair and walked out with the parts . After it failed a week later ( little use ) I asked the friend and sent him a tag shot , text me back and said don't waste your money , 200v is gonna run hot , replace it . So I followed rule two , friends and my common sense ( is it a logical reason , yes ) have not let me down yet , I bought a new one . I know little about electronics and at my age there are other things I'd prefer to learn . Besides electronics was my first choice for trade school ( thought I new everything about woodworking already ) . Did fine in math and related but when I sat down at the bench for hands on the teacher called me aside and said " did you know your colorblind " that was the end of that .

 

[Milton Shaw]

Nobody else has mentioned this but make sure the motor is turning off by the pressure switch and not some other way. Most of the 5HP and up compressors the pressure switch has to cut the motor off for the unloader to let the pressure off. A check valve bad would make the motor try to start at full load which would make the motor burn out soon even if it tripped the overload. I have seen and read here where people put switches to remote control their compressors which would leave the unloader off and the compressor and motor at full tank pressure unless its valves are leaking so much the check valve activates.

 

[toplessHO]

you might have missed the part about owner telling me the unloader was working fine.
I will check this thing out 3 ways to Sunday when I get it going again.
Owners a paint and body man not an electric motor guy so wouldnt expect him to know much about this.

 

[toplessHO]

picked up motor today
got the 6 HP one at Tractor Supply
Manager let me use the 10% off coupon I got in mail
which had already expired.
Found out they offered a 3 year warranty for $40.
was a no brainer to get 3 additional years on top to the 1 yr factory warranty
and if you add in the 10% off it was only $9 more.
seems to line up just fine even tho its a 56 frame .
Next weekend may tackle wiring it up.

 

[toplessHO]

got the thing wired up and fired it up.
Owners first words were WOW it doesnt strain at all.
Checked amps and was pleasantly surprised that it was only 14.5A.
So yes the true 6HP is a little over sized,but hasnt hurt a thing by being big.
So I told the owner if he wanted to get a little brave he could change size of pulley on motor and gain a few CFM. The pump on this appears to be decent,cast iron Made In USA.All in all everyone is happy with the choices made here,4 yr warranty,plenty of power.We need to run it good and hard and see what the temps are.

 

[wyliesdiesels]

got the thing wired up and fired it up.
Owners first words were WOW it doesnt strain at all.
Checked amps and was pleasantly surprised that it was only 14.5A.
So yes the true 6HP is a little over sized,but hasnt hurt a thing by being big.
So I told the owner if he wanted to get a little brave he could change size of pulley on motor and gain a few CFM. The pump on this appears to be decent,cast iron Made In USA.All in all everyone is happy with the choices made here,4 yr warranty,plenty of power.We need to run it good and hard and see what the temps are.

No way is that a 6HP motor. Its closer to 3HP

Typical 5HP motors have an FLA of 20-23a and the NEC lists an FLC of 28a.

 

[American Locomotive]

No way is that a 6HP motor. Its closer to 3HP

Typical 5HP motors have an FLA of 20-23a and the NEC lists an FLC of 28a.

Current depends on the load. The compressor won't get to full load until there's ~150 psi in the tank.

 

[toplessHO]

No way is that a 6HP motor. Its closer to 3HP

Typical 5HP motors have an FLA of 20-23a and the NEC lists an FLC of 28a.

Im really surprised you would answer like that.
This motor is loafing
proof that the old motor was over rated and was closer to 3 HP vs 7 HP
Are you missing the entire purpose of this thread?

Revisit what the "F" means in FLA

I will go back and take a full scale reading when I can get some time.
I may also readjust the pressure switch to the advertised 175PSI as the owner has dropped it to 140,and see what it pulls.
Owner says none of the 3 previous ones sounded as effortless in starting as this one.

 

[mm08822]

This motor is loafing
proof that the old motor was over rated and was closer to 3 HP vs 7 HP

I will go back and take a full scale reading when I can get some time.
I may also readjust the pressure switch to the advertised 175PSI as the owner has dropped it to 140,and see what it pulls.
Owner says none of the 3 previous ones sounded as effortless in starting as this one.

"So I told the owner if he wanted to get a little brave he could change size of pulley on motor and gain a few CFM."

The new motor does seem to be just loafing based upon your operating data point. Not sure where in the pressure-build cycle you measured 14.5A, but at that instant, it is about 3.6 HP (assuming 80% efficiency).

The original WEG HP was ~ 4.1HP (assuming 80% efficiency at NP V& FLA.)

The new “6HP” motor is ~ 5.7HP (assuming 80% efficiency at NP V& FLA.)

It’s a little concerning that you can’t find the new motor on Marathon’s website.

5 out of the 8 reviews on TSC for this motor rated it a 1 out of 5 because it failed. I would be very hesitant to change PS settings or pulleys to further load this motor. Otherwise you might become #6 out of 9. Even with a warranty, you’ll get tired of changing out this motor. I’d leave good enough alone. JMO.

 

[toplessHO]

Im upping the pressure switch to the factory levels to see if this motor is capable.
I will lower it back down after testing.
I dont put alot of faith in those reviews,happy people arent as likely to brag as unhappy ones are to complain.

 

[6PTsocket]

For that motor to be 3.3HP @ 16.5A @ 230V, it'd have to be 65% efficient. That just doesn't happen with modern electric motors. I don't think you can even legally sell a standard frame motor that's only 65% efficient anymore. Looking around online shows that motor is rated for 4 HP.

In comparison, a modern 5HP high-efficiency motor from Baldor has a nameplate current of only 19 amps.

I've never seen "200v" rated motor. I've seen dual-rated 208/230v motors, but that has to do with 208v "wye" 3-phase power.

They work on either 208 or 230 but they lose a bit. I had a window air conditioner rated that way with two BTU ratings, depending on the voltage. I was stuck with 208 so it paid to buy a 208 to 230 autoformer to step it up.

Sent from my SM-G900V using Tapatalk

 

[toplessHO]

so heres some more info on the new "6HP " one
cranked the PS up to the 175 PSI that unit was shipped as.
thats the higher reading
adjusted it back down to 150psi and amps dropped to 15.65
will keep it at 150 but may change pulley size to allow faster fill ups