replacement for Husky 7.5 compressor motor

toplessHO · Jul 4, 2017

so friend says its gone thru 2 replacement motors.
I havent had a chance to check anything out but
did get a pic of data plate.
HP is labeled "spl" which in my book is termed "special" or "BS".
too much of this misleading info out there,so you can sell a 3.3HP
compressor as a 7.5 HP one.
I suspect others have had this same problem .
So rather than declare my self insane by replacing it with the same motor
Im looking at larger replacements.
Surplus Center has a couple 56 frame 5 HP ones but would need to replace
the drive pulley as the replacement motor is only 5/8 shaft instead of 3/4.
For comparison Ive taken a data plate pic of the "smaller" Devilbis which is closer to a real compressor.

toplessHO · Jul 4, 2017

heres the devilbis,which is advertised as 6.5
but suspect its truly a 5HP

EOC_Jason · Jul 4, 2017

If he's burning up motors I would check the electrical coming in to make sure all connections are tight and proper voltage. Likewise with the belt off the pump I would make sure the pump spins okay by hand. Maybe check / change the oil if it hasn't been done in a while.

Don't even bother with "HP" claims... Find a replacement based on rated amps and frame mount.

American Locomotive · Jul 4, 2017

Based on the current, I'd estimate that Weg motor is around 4HP or so.

joe_padavano · Jul 4, 2017

American Locomotive said:
Based on the current, I'd estimate that Weg motor is around 4HP or so.

Probably even less than that at 16-ish amps. The other one is about 4.5-5 HP at 23.5 A.

toplessHO · Jul 4, 2017

if you look Ive already run the calcs
3.3 HP for the Husky
4.9 (5) for the devilbis

Compressor has been at 3 different locations
first one was his commercial shop which previous compressor lasted 20 yrs with same wiring at same location.
Ive never had the chance to check anything out while it was running,hes always "fixed it" himself.
Im going to replace the WEG with a good brand name 5HP one,just havent found a reasonable priced 143 frame

rnscustom · Jul 4, 2017

I bought a used compressor and it kept overheating and blowing capacitors . Come to find out it was a 230v motor and we are 220v here , you wouldn't think that would matter but when I text a photo of the tag to engineer friend said that's your problem . Been fine since the new baldor. Get a baldor , can be had on eBay for around 300 . 5hp should work fine , mine actually came from a Boston supplier . They also sell new motors that are removed for swaps that you can bid on, weco is the company . Nice people and all quality at great prices

toplessHO · Jul 4, 2017

most motors are rated at 200 v now for that reason
that engineer fed you some BS
lots of stuff comes into play on motors
HP,volts,service factor, temp rating,duty cycle etc
havent looked on epay yet,just grainger and surplus center

American Locomotive · Jul 4, 2017

toplessHO said:
if you look Ive already run the calcs
3.3 HP for the Husky
4.9 (5) for the devilbis

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.

toplessHO said:
most motors are rated at 200 v now for that reason

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.

manwithtools · Jul 4, 2017

American Locomotive said:
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.

Actually you probably have seen many of them. Motors are typically rated for +/- 10% voltage operation. That's why a "220" motor will work on 200, 210, 215, 220, 230 or 240 volts. Norcal will be here shortly to remind us there is no such thing as "220" any more :lol:

, even though some places at the end of a long service with heavy loads, actual voltage will be close to 225 or so. :beer:

From US Motor's web site:
"In accordance with NEMA MG 1, 12.44, motors shall operate successfully under running conditions at rated load with variation in the voltage up to the following percentages of rated voltage:
Universal motors except fan motors - plus or minus 6 percent (with rated frequency).
Induction motors - plus or minus 10 percent (with rated frequency)."

Plenty of single phase motors are rated at 115/ 208-230 operation. if you alter 208 volt by less than 5%, you will be at 200 volts and the motor will still operate fine. At the lower voltage it will run a little warmer, but only in a rare instance is a motor loaded to it's full rating and hence it may never make a difference in the life of the motor.

manwithtools · Jul 4, 2017

rnscustom said:
I bought a used compressor and it kept overheating and blowing capacitors . Come to find out it was a 230v motor and we are 220v here , you wouldn't think that would matter but when I text a photo of the tag to engineer friend said that's your problem . Been fine since the new baldor. Get a baldor , can be had on eBay for around 300 . 5hp should work fine , mine actually came from a Boston supplier . They also sell new motors that are removed for swaps that you can bid on, weco is the company . Nice people and all quality at great prices

That's some engineering malarkey speech right there....

For one, it's doubtful you are actually 220 volts.

For another, the motor could care less about 10 volts difference in supply, that's less than 5% of nominal.

You replaced a junk used motor with a good motor and your problems went away. No surprise there.

Norcal · Jul 4, 2017

A 200V motor is the rated voltage for use on a 208V supply NEMA changed the rated voltage to 200V a few years ago so a tri volt motor is 115/200-230, 200-230/460 instead of the 115/208-230, 208-220/440, or 208-230/460V used in the past.

manwithtools · Jul 4, 2017

It's all a bit confusing, the motor nameplate voltages are "utilization" voltages, not utility nominal voltages. There is an assumption made that the utility will deliver to you with a bit of voltage loss and your infrastructure will add to this loss a bit further.

Think of it as a GJ member. Utility provides 234 volts to your meter (because you are on a long dead end road - like me). I then run 400 feet to my shop using a slightly conservatively sized conductor for my expected 100 amp load.

Now I have my buddies over to work on four vehicles at once (Air compressor, Plasma, lift, AC, grinders and welders and most importantly - beer fridge) and suddenly my voltage at my compressor is 221 volts (or even 207 volts) due to voltage drop on my shop service. A properly constructed motor won't care the least about this. It's rated from 200 - 230 volts and all of this fits within that range. The range is even large if we factor in the +/- 10% of nominal

That's why NEMA specifies motors to have such a wide range of operation.

pancho400cid · Jul 4, 2017

Are you sure the old motor had a 3/4" shaft diameter?

That is an old standard, not used on modern "standard" motors. OTOH your AO Smith motor is a 184Z frame and "Z" means special shaft extension.... so it's possible.

If you are burning up WEG motors, it's probably safe to assume the motor is drawing considerably more than "service factor" current which is at least 1.15 x 16.5 = 19 amps approx. Since a compressor has a duty cycle by definition (hence the "SPCL" HP rating to take advantage of that fact) it is likely drawing WAY over 19 amps.... either because of low voltage, poor connections/small wiring or because that is what the compressor needs or all the above. You really should check the voltage at the motor terminals with the compressor running near full shut-off pressure (max motor load) to know what you've got... hard to do if the compressor is dead I realize.

Assuming the voltage is close to motor NP voltage (some tolerance there per previous posts), I would say look for a compressor duty motor with a rated running current around what the AO Smith motor had (23 Amps @ 240 VAC).

manwithtools · Jul 4, 2017

Great point, if you are burning up a WEG motor (which are great quality BTW) you (he) have some other issues.

toplessHO · Jul 4, 2017

^ hence why Im looking for a real motor for him. Yes I will check it out when I put it together for him. He was measuring shaft with tape measure,has no mics,so I told him a poor mans caliper is an open ended wrench. Its 7/8 inch shaft.....So back to finding a motor.
143/145 frame,7/8 shaft somewhere around 2.25 inch long/w keyway.5 true HP.
I have no idea what direction the motor needs to rotate so to be safe will get reversible
(that is unless someone has same compressor and can verify its CCW rotation)
I believe this Husky is made by Campbell-Hausfeld ) which in my book is low end.

6PTsocket · Jul 4, 2017

manwithtools said:
Actually you probably have seen many of them. Motors are typically rated for +/- 10% voltage operation. That's why a "220" motor will work on 200, 210, 215, 220, 230 or 240 volts. Norcal will be here shortly to remind us there is no such thing as "220" any more [emoji38], even though some places at the end of a long service with heavy loads, actual voltage will be close to 225 or so. [emoji481]

From US Motor's web site:
"In accordance with NEMA MG 1, 12.44, motors shall operate successfully under running conditions at rated load with variation in the voltage up to the following percentages of rated voltage:
Universal motors except fan motors - plus or minus 6 percent (with rated frequency).
Induction motors - plus or minus 10 percent (with rated frequency)."

Plenty of single phase motors are rated at 115/ 208-230 operation. if you alter 208 volt by less than 5%, you will be at 200 volts and the motor will still operate fine. At the lower voltage it will run a little warmer, but only in a rare instance is a motor loaded to it's full rating and hence it may never make a difference in the life of the motor.

Usually 208/230 motors are derated at the lower voltage. They are lower power by a not insignifucant amount. I had an air conditioner rated 208/230, with different BTU ratings for each voltage. As I only had 208 it paid to buy a 208 to 230 step up transformer for a measurable improvement in performance.

Sent from my SM-G900V using Tapatalk

manwithtools · Jul 4, 2017

6PTsocket said:
Usually 208/230 motors are derated at the lower voltage. They are lower power by a not insignifucant amount. I had an air conditioner rated 208/230, with different BTU ratings for each voltage. As I only had 208 it paid to buy a 208 to 230 step up transformer for a measurable improvement in performance.

Sent from my SM-G900V using Tapatalk

No, they are not, did you read my earlier post? 208/230 derated compared to what? You're comparing apples to oranges. AC hermetically sealed motors work under a completely different system. Induction motors driving a compressor are different than a HS HVAC sealed compressor motor.

rnscustom · Jul 4, 2017

Could have been bs , it was the original motor from ingersoll , when I contacted them they also stated that that motor was not one they sold to my area . I put the new baldor on and it's been fine , same hp , breaker , and wiring so his advice to change it was a cure right or wrong . Paid $400 for the compressor and $300 for a new motor $700 for a ingersoll T30 . Could be wrong in the 230v either way ingersoll , engineer and motor rebuilder said replace it . 300v?? Point was that was my reason I kept popping breakers and overheating . Didn't save the tag photo

wyliesdiesels · Jul 4, 2017

American Locomotive said:
Based on the current, I'd estimate that Weg motor is around 4HP or so.

joe_padavano said:
Probably even less than that at 16-ish amps. The other one is about 4.5-5 HP at 23.5 A.

ITs somewhere between 3 and 4HP.

NEC FLC for 3HP is 17a...and most newer 3HP motors are well below that.

rnscustom said:
I bought a used compressor and it kept overheating and blowing capacitors . Come to find out it was a 230v motor and we are 220v here , you wouldn't think that would matter but when I text a photo of the tag to engineer friend said that's your problem . Been fine since the new baldor. Get a baldor , can be had on eBay for around 300 . 5hp should work fine , mine actually came from a Boston supplier . They also sell new motors that are removed for swaps that you can bid on, weco is the company . Nice people and all quality at great prices

Thats a bunch of bull as ManWithTools pointed out. Is this friend an actual "engineer"? Cause he should know the following....

There is no more 220v first of all. IF your actual meter reading on your service is 220v, you have some serious voltage drop issues.

Nominal utility voltage is 208v/120v or 240v/120v single and 3 phase.

230v rated motors are designed for 240v systems.

Running a 230v rated motor on a 240v system wouldnt kill it at all since over current NOT over voltage is what kills motors. And running a motor at a slightly higher voltage actually causes the motor to use less current NOT more current. Excess current is what creates overheating in the windings.

Did this motor have a starter with overload/heaters or integral overload(red button on end)? The breaker for motor circuits isnt designed to and shouldnt be relied on for overcurrent protection. That is the job of the aforementioned overloads...the breaker only provides short circuit and ground fault protection hence why they are allowed and are typically oversized....

Again, thats a bunch of BS your friend told you... :monkey_po

manwithtools · Jul 4, 2017

Well, thank you for confirming everything I stated earlier without quoting my posts. Happy 4th of July wylie!

wyliesdiesels · Jul 4, 2017

manwithtools said:
Well, thank you for confirming everything I stated earlier without quoting my posts. Happy 4th of July wylie!

sorry to offend you. Didnt mean to... But yes I agreed with what you said.

I for the most part dont quote others to say agreed unless it is a short thread. I try to just point out the BS otherwise if i quoted and said agreed to everyone i agreed with my whole reply would be very long...

I went back and edited my last comment to give you credit... :thumbup:

Happy 4th to you too...

walta · Jul 4, 2017

Before you declare the current motor dead, open it up and locate the fault. As long as the windings are not charred the motor is likely repairable.

How often was the operator the resetting the motors overload button?

Are you sure the factory pulleys are currently installed?

Whatever motor you install take the time to measure the current it is drawing, just as the tank getting to max pressure. If it is more than the number on the motors name plate plus 10%, the motor pulley is too large for your load.

Walta

toplessHO · Jul 4, 2017

Im told its never been changed other than direct replacement motors
pulley is 6 inch which seem kinda large if you ask me.
Whats happened before now is water under the bridge.
New motor will get some attention when installed and on start up.

toplessHO · Jul 4, 2017

The more I read about these motors marked SPL the less I like it.
Take for instance the 5 HP one
its got the starting torque of a 5 HP but the running capacity of a 3HP.
this leads me to think that in truth its a 3HP motor with a little more push from larger cap.

rnscustom · Jul 4, 2017

Ok , did find a photo of the tag , reads 200v . Either way new motor was my answer . Put 4 capacitors , set of contacts , and new bearings plus my time ,

toplessHO · Jul 4, 2017

found a few that looks promising
this 5 HP looks like a true 5 HP not the reduced BS
just made in Mexico grrrr
https://www.tractorsupply.com/tsc/product/marathon-electric-air-compressor-motor-5hp?cm_vc=IOPDP1
I like this one even better but dont see how 1 HP more can add only 1 amp
https://www.tractorsupply.com/tsc/product/marathon-electric-air-compressor-motor-6-hp?cm_vc=IOPDP1

But look at this one and explain how 5HP can only draw 15 amps(more BS ratings)
https://www.surpluscenter.com/Elect...0-RPM-LEESON-AIR-COMPRESSOR-MOTOR-10-2530.axd

snyder · Jul 5, 2017

Is it possible that during one of the earlier motor replacements that the rpm got changed from 1750 to 3450. And this is stressing the new motors.?

rnscustom · Jul 5, 2017

http://www.practicalmachinist.com/v...-and-vfd/run-200-volt-motor-230-volts-102476/

Aceman · Jul 5, 2017

snyder said:
Is it possible that during one of the earlier motor replacements that the rpm got changed from 1750 to 3450. And this is stressing the new motors.?

I agree. This is how I'd troubleshoot it.

1. Verify the motor rpm from the factory.
2. Replace the motor and verify the overloads for the motor are installed and set correctly, if they're adjustable.
3. Verify voltage to the motor is correct under load AND all the way through startup.
4. After the motor is connected, verify the pump is being driven at the correct speed with a tach, unless your friend is 100% sure the pulley sizes have never been changed.
5. Amp the motor under load all the way up to when it cycles off.
6. Verify the unloader valve is working correctly when it cycles off, if it has one. They usually do at this size compressor.
7. Verify the pressure switch hasn't been adjusted beyond what the compressor and motor are rated to produce.

I also want to make a note or FYI, that this is why you size wire to the NEC tables, rather than the motor nameplate. There are no guarantees every motor will draw the same current, the NEC tables have already taken that into account and that is the reason they are used for sizing motor circuits.

toplessHO · Jul 5, 2017

unfortunately most of this cant be checked without a new motor
First question I asked was about unloader. He claims thats working fine.
Next was how did he get replacement motor,answer was he called Cambell-Hausfeld
directly and ordered the motor using his serial number.
Im going to call them directly and ask some questions. Hes never touched the adjustment on pressure switch,and it was new when he got it.

toplessHO · Jul 5, 2017

rnscustom said:
http://www.practicalmachinist.com/v...-and-vfd/run-200-volt-motor-230-volts-102476/

dont confuse things they are talking about a rotary phase converter
using a 3 phase as an idler
if the new motor you have is rated at 200/230 and works fine whats your question?

rnscustom · Jul 5, 2017

No question . The old motor was 200v single phase . Overheated and went thru capacitors , was just giving my experience with my compressor motor issue in hope to help others , which I thought this forum was for . Just noticed that article was for 3 phase but I would think the voltage rule would be the same too much voltage would overheat the motor (200v motor ) . I was comfortable with the professionals telling me to just replace it and stop putting money into it for voltage reasons .

alfredeneuman · Jul 5, 2017

rnscustom said:
Come to find out it was a 230v motor and we are 220v here , you wouldn't think that would matter but when I text a photo of the tag to engineer friend said that's your problem

Your engineer friend is "misinformed" by 13 volts

http://www.ecmweb.com/motors/how-precise-are-motor-nameplate-ratings

An excerpt from this article......
"NEMA (voltage variation). The tolerance for voltage variation under running conditions in NEMA Std. MG 1, 12.44, is ±10% of rated voltage at rated frequency."

rnscustom · Jul 5, 2017

Corrected that post saying I wrote the wrong voltage in the first post . Motor was 200v . So still wrong ??

rnscustom · Jul 5, 2017

Compressor motor running a die grinder on a 90+ degrees day . That motor got hot .

wyliesdiesels · Jul 5, 2017

rnscustom said:
Corrected that post saying I wrote the wrong voltage in the first post . Motor was 200v . So still wrong ??

So then it should be on a 208v system

rnscustom said:
Compressor motor running a die grinder on a 90+ degrees day . That motor got hot .

So put a fan on it

rnscustom · Jul 5, 2017

Your probably right , next time I'll look here on the forum for 5 days with everyone's opinion who can't physically see the motor go out and buy $$ worth of equipment to test the motor , then spend $400 and a month at the rebuilders . Motor was in and done in 3 days . Kids are back working on their cars in the garage .

manwithtools · Jul 5, 2017

10% of 200 volts is 20 volts, so your 200 volt motor should have operated properly @ 220 volts. If it was a cheap motor with lower class insulation on the winding's, it could be very hot as you describe.

rnscustom · Jul 5, 2017

Previous poster stated there is no way your at 220 , another stated probably more like 225 . Anyway there is a variable that could or could not bring me beyond the 10% . Was my friend correct in telling me to get a motor rated for closer to what your have in your area . Has it been trouble free since . Yes so my only point to the original poster was you need a motor , go buy the correct one and move along . Check your wiring and keep an eye on it .

replacement for Husky 7.5 compressor motor

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