# Single phase 5hp motors - Baldor vs WEG?



## FlyFishn (Dec 29, 2020)

I have always heard of Baldor motors being quality machine motors over the years. I had another thread going (link below) to searching for an air compressor. I think I am settling in on a Sailor-Beall 5hp unit/735 pump (probably 60gal vertical, possibly 80gal). They have a choice of the two motors (Baldor or WEG) and from what I hear WEG may have the edge on customer service after-sale. Can anyone offer any comments? Has anyone had any negative experiences with either? 









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I have an old 20gal/110v compressor that I am a bit scared to use now - the tank is rusted (stuck a borescope thru a port on the tank). I know where the compressor came from it wasn't overly well taken care of, either, but after researching compressors and seeing the aftermath of compressor...




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## JimDawson (Dec 29, 2020)

Interestingly I have both motors (sort of)  I have one compressor (red) that the Leeson motor failed on it after about 25 years, I replaced it with a Baldor compressor duty motor which failed after about 2 years.  I use quite a bit of air now so it cycled a lot, unlike the first many years of compressors life.  As a stand by, I had another 5hp compressor (black) (maybe 4 years old) that a customer gave to me when it's single phase motor failed.  Like mine, it cycled a lot also.  The good news is that I had already purchased a WEG motor to replace that failed motor, and had it ready to install on the black compressor in case the red compressor failed again, which it did.

However, the WEG motor is 3 phase.  I decided on 3 phase because what was failing on the single phase motors is the centrifugal start switch, in all 3 cases.  I bought a cheap Huanyang 10HP VFD to run it.  https://www.amazon.com/Variable-Fre...ld=1&keywords=10+hp+vfd&qid=1609287821&sr=8-2

I set the VFD to accelerate to speed over 10 seconds, and the start current never goes over the normal running current.  A nice soft start.  I run my shop air at 125 PSI (rather than the 175 PSI that the compressors are rated for) with a 5 PSI differential so it cycles a lot.  I've not had any problems since I installed this about 2 years ago.


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## mksj (Dec 29, 2020)

When I bought my Champion 5Hp compressor about 4 years ago, they had switched to WEG motors instead of Blador. When I spoke to their rep. they said they were having more reliability issues with the Baldor. They still seem to come with either WEG or Baldor, not sure if it is a cost, supply or reliability issue. Also depends on the duty cycle, frequent start/stops will probably shorten any single phase motor's lifespan. I haven;t had any issues with my WEG, and do not run my compressor often enough to warrant 3 phase. Can't really say if one is better than another, but for frequent use 3 phase may be a better option.


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## FlyFishn (Dec 29, 2020)

JimDawson said:


> The good news is that I had already purchased a WEG motor to replace that failed motor, and had it ready to install on the black compressor in case the red compressor failed again, which it did.
> 
> However, the WEG motor is 3 phase. I decided on 3 phase because what was failing on the single phase motors is the centrifugal start switch, in all 3 cases......
> 
> I set the VFD to accelerate to speed over 10 seconds, and the start current never goes over the normal running current. A nice soft start.


Interesting information.

A couple questions.
1. How hard is it to replace a centrifugal start switch? As in - it would make sense to have spares on-hand from what you say, not that down'ing a compressor for the repair would be much fun but it would be a way to get back in gear perhaps - unless it is too big of a rebuild where a motor replacement would be a better option? I would find the replacement being a better option hard to believe on "quality" motors, though.

2. Do you know what kind of amperage or wattage your set up with the 3 phase VFD draws on input single phase? What line voltage (actual, not class - like my line voltage here is 245v, not "240", "230", or "220")

3. I thought motors for running VFD with had to be made for VFD. Physically the speed control with VFD on a non-VFD motor "works", but it will vastly shorten the life of the motor from what I have known on the subject. How does this line of thought fit with your motor set up? Is your WEG capable of VFD? Or is it a single-speed/non-VFD? Did WEG give you any guidance on motor selection for this application or is it something you came up with on-the-fly?


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## JimDawson (Dec 29, 2020)

FlyFishn said:


> Interesting information.
> 
> A couple questions.
> 1. How hard is it to replace a centrifugal start switch? As in - it would make sense to have spares on-hand from what you say, not that down'ing a compressor for the repair would be much fun but it would be a way to get back in gear perhaps - unless it is too big of a rebuild where a motor replacement would be a better option? I would find the replacement being a better option hard to believe on "quality" motors, though.



It just requires a motor teardown.  But there could be other damage to the motor also.  Frankly I never looked at the motors beyond confirming the centrifugal switch was fried, before I tossed them in the scrap bin.



> 2. Do you know what kind of amperage or wattage your set up with the 3 phase VFD draws on input single phase? What line voltage (actual, not class - like my line voltage here is 245v, not "240", "230", or "220")



At 240V, the max load on my single phase line is 23 amps, right at the nameplate amps for a 5HP motor.



> 3. I thought motors for running VFD with had to be made for VFD. Physically the speed control with VFD on a non-VFD motor "works", but it will vastly shorten the life of the motor from what I have known on the subject. How does this line of thought fit with your motor set up? Is your WEG capable of VFD? Or is it a single-speed/non-VFD? Did WEG give you any guidance on motor selection for this application or is it something you came up with on-the-fly?



Most modern motors with class''H'' insulation are just fine on a VFD.  Consider that most 3 phase motors are dual voltage (230/460 in North America).  What kills motors is the ''spikey'' output from a VFD, actually punches through the insulation.  Since we are running them at half of their max rated voltage, it's really not an issue.  The actual insulation in the motor is most likely rated at 1000 - 1200 volts.  In my 40 or so years of hanging VFDs on motors, I have never seen a failure.  I have been running VFDs on my machine tools for years, and have installed many on non-inverter rated motors over the years in many applications.

I didn't ask for any guidance from WEG, in fact, I purchased that motor from a guy on Craigslist for $125.  It was brand new, never used.  I know the brand so just went off of my experience.


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## Larry$ (Dec 29, 2020)

WEG motors, at least the 40hp one on my vacuum pump, are made in Brazil. It has been running fine for 8 years. I think the worst thing about VFDs is people use them to run motors too slow. The motor fan then doesn't provide much for cooling.


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## f350ca (Dec 29, 2020)

The Baldor draft motor on my boiler died a couple of years ago, when I went to replace it the chap at the rewind shop recommended Weg over Baldor, said they were a lot more reliable. Went for the Weg replacement, I could always hear the Baldor when I left the house if the boiler was running, when I hooked up the Weg I checked to make sure it was 3600 rpm motor as it was so quiet. Still quiet.

Greg


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## Ulma Doctor (Dec 30, 2020)

Baldor used to be great name for motors, the old 3 phase motors lasted forever.
i think that they are trying too hard to make cheaper motors now.
the better than it has to be mentality, is sadly, dead.
the Baldor motors are still good.
i have used WEG motors to retrofit drive systems, in abusive environments- they have proven to be good motors. 
IMHO the WEG motor is a better motor nowadays


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## FlyFishn (Dec 30, 2020)

JimDawson said:


> Most modern motors with class''H'' insulation are just fine on a VFD. Consider that most 3 phase motors are dual voltage (230/460 in North America). What kills motors is the ''spikey'' output from a VFD, actually punches through the insulation. Since we are running them at half of their max rated voltage, it's really not an issue. The actual insulation in the motor is most likely rated at 1000 - 1200 volts. In my 40 or so years of hanging VFDs on motors, I have never seen a failure. I have been running VFDs on my machine tools for years, and have installed many on non-inverter rated motors over the years in many applications.



Good information. Thank you for the detail. 

As for the original subject of the thread - from the replies in the thread I'd say it's pretty conclusive that WEG is the better motor today. Thanks for the info everyone, as always.


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## pacifica (Dec 30, 2020)

I have weg 5hp single phase on my compressor, it runs about an hour a day and is 5 years old. Works great. I bought it over baldor or leeson because at the time it cost 30% less. 
I also have a 2 hp baldor on my belt grinder ( 3 phase) which is quiet, powerful and shows less than a ten-thousandths run-out on the spindle shaft.


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## FlyFishn (Jan 2, 2021)

JimDawson said:


> It just requires a motor teardown.  But there could be other damage to the motor also.  Frankly I never looked at the motors beyond confirming the centrifugal switch was fried, before I tossed them in the scrap bin.
> 
> 
> 
> ...



I did some searching on VFD's this evening. It looks like the highest HP rating for a single-phase input/3-phase output VFD is 5hp. 

I was tossing the idea around of a 7.5hp compressor motor with 3-phase via VFD. However, it does not appear there is such a VFD to handle the size motor from a single-phase service. So that puts me back to the 5hp class.


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## mksj (Jan 3, 2021)

You can use a 15Hp 3 phase input VFD on single phase but it needs to be derated around 2 to do so, this varies by manufacturer/model. Basically when you purchase a single phase input VFD it is similar to a larger 3 phase input VFD. It has to do with the amount of ripple/THD and current spikes generated when feeding it single phase as opposed to 3. Problem with that route is it is a tough load, and a decent 15 Hp VFD is going to run you quite a bit and require a very big breaker/wiring. Technically the input wiring has to be rated for the total VFD capacity and not the load it is driving, the rating for the WJ200-110LF specifies 80A fusing with #4 wire. You would be much better off just getting a 7.5Hp single phase compressor which would be about 1K cheaper, take a smaller breaker and be a lot easier to install. 

You can buy HY VFD's supposedly rated for single phase input, but others have pointed out that it is a bit misleading advertising. Compressors are a difficult load, most people using these generic VFD's significantly up-size them. If you read the reviews on say Amazon, they are not favorable in this application.


​​


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## FlyFishn (Jan 4, 2021)

JimDawson said:


> I decided on 3 phase because what was failing on the single phase motors is the centrifugal start switch, in all 3 cases.


It sounds like the mag start option is in addition to the centrifugal start switch and is adjustable. Would the mag start alleviate the wear on the centrifugal start switch if it is set for lower inrush current? 

I am thinking just keeping things single phase and having all the necessary parts on hand to swap in should something go is going to be the route Ill go. I suppose having a 2nd motor would be the next option for a quicker way to get back running then rebuild the other one. Im not sure a 2nd motor is in the cards off the bat, though.

I talked to a guy at Saylor Beall today and he said they like to stick to Baldor in the 5hp class then switch to WEG with 7.5hp on up. I didnt get many details as to why other than Baldor seemed to have a good product there and they like to keep everything made in USA as best they can, where WEG is not US made.


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## Janderso (Jan 4, 2021)

Ulma Doctor said:


> the Baldor motors are still good.


Mike, don't you think the industrial baldor motors are still excellent motors? The reason I say that, we have Baldor Industrial (10hp) in our stationary high pressure pumps that run the two car wash wands. They go 9-10 hours a day 6 days a week almost non-stop. Never an issue with the Baldors.


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## JimDawson (Jan 4, 2021)

FlyFishn said:


> It sounds like the mag start option is in addition to the centrifugal start switch and is adjustable. Would the mag start alleviate the wear on the centrifugal start switch if it is set for lower inrush current?



No, not at all.  Also there is no adjustment on a mag starter, it's just a big relay.  Either on or off.

Edit:
You may be thinking about the overload adjustment, this is only for motor overload.  Has no effect on the inrush current.  The centrifugal switch sees motor locked rotor current on startup.


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## FlyFishn (Jan 4, 2021)

JimDawson said:


> Also there is no adjustment on a mag starter, it's just a big relay.


Either I was told wrong or there was a miscommunication/misunderstanding when I talked to the guy at Saylor Beall. He said the mag start was "adjustable". Maybe I didn't interpret what he said correctly then. How I interpreted it was the mag start being "adjustable" would allow the inrush current to be adjustable = softer start if desired.


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## pacifica (Jan 4, 2021)

FlyFishn said:


> I did some searching on VFD's this evening. It looks like the highest HP rating for a single-phase input/3-phase output VFD is 5hp.
> 
> I was tossing the idea around of a 7.5hp compressor motor with 3-phase via VFD. However, it does not appear there is such a VFD to handle the size motor from a single-phase service. So that puts me back to the 5hp class.


You can also look at a 2 stage compressor to get more cfm from the 5 hp and a larger tank.


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## JimDawson (Jan 4, 2021)

FlyFishn said:


> Either I was told wrong or there was a miscommunication/misunderstanding when I talked to the guy at Saylor Beall. He said the mag start was "adjustable". Maybe I didn't interpret what he said correctly then. How I interpreted it was the mag start being "adjustable" would allow the inrush current to be adjustable = softer start if desired.



A motor starter consists of two parts: The contactor, just a big relay. And the overload relay. Some overload relays are adjustable for current, but has nothing to do with inrush, only the motor running current.  Are normally set to trip at a 125% overload.

The only way to get a soft start is with a soft starter, a rather expensive device. https://www.automationdirect.com/adc/shopping/catalog/motor_controls/ac_motor_soft_starters


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## pacifica (Jan 4, 2021)

FlyFishn said:


> It sounds like the mag start option is in addition to the centrifugal start switch and is adjustable. Would the mag start alleviate the wear on the centrifugal start switch if it is set for lower inrush current?
> 
> I am thinking just keeping things single phase and having all the necessary parts on hand to swap in should something go is going to be the route Ill go. I suppose having a 2nd motor would be the next option for a quicker way to get back running then rebuild the other one. Im not sure a 2nd motor is in the cards off the bat, though.
> 
> I talked to a guy at Saylor Beall today and he said they like to stick to Baldor in the 5hp class then switch to WEG with 7.5hp on up. I didnt get many details as to why other than Baldor seemed to have a good product there and they like to keep everything made in USA as best they can, where WEG is not US made.


Also might be that the Baldor's cost more.


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## mksj (Jan 4, 2021)

How many hours per day and the type of CFM or cycles/hr are you looking at? Single phase motors go for many years, and in my limited experience the start capacitor is the first to go. Never had to replace the start switch, but they are available for the WEG motors on-line for $35-50. Certainly a lot less expensive than replacing the motor. As Jim pointed out, there are thermal overload devices that attached on the contactor typically seen with the better compressors at 5 Hp and higher. This can be either fixed overload heaters or variable overload relay with a limited adjustment range and set by the manufacturer. Adjustments do not effect starting current. Soft start would be overkill and costly, they cost as much as a VFD and not sure how they would effect the start switch life. There are also solid state single phase motor starters, although I have only read about them.

With a two stage compressor, you have an unloader which softens the starting load, you can also set them for continuous run if you were doing something like sand blasting.


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## FlyFishn (Jan 4, 2021)

The compressor I am looking at is a 2 stage Saylor Beall.

Originally I was looking at the 5hp motor compressors as that was the biggest motor I felt I could run. The idea of the 3 phase motor run off a VFD gave me another thought to look at. That would have changed the ballgame a bit on CFM - from 17.3 on the 5hp units I was looking at to 26.9cfmon the 7.5hp units - almost 10cfm more. However, after looking at the VFD's that would run that size motor I think that is too far deep in to "uncharted waters", in my book, and the power supply (service) to run it seems too questionable at this point in my studies to try and wrap my mind around it. So I am back to the 5hp units. That would be the 705 pump (it is a 2 stage, but it has both cylinders in the same casting = it does not have 2 castings, just 2 cylinders in 1). The 707 pump is a 2-casting pump - which is an option on the 5hp, but nets less than 1.5cfm more (18.5 with the 5hp driven 707 pump vs 17.3 with the 5hp driven 705 pump). The last consideration is the tank. Originally I was looking at 60 gallon vertical compressors for reason of floor space taken up more than anything. However, once you're in the threshold of a $3500 compressor there isn't much difference in cost between the tank sizes. The floor space consideration is still a consideration - I will have to chew on that a bit. As far as the original subject of the thread - motors - the 5hp motors are where I am (paired with the 705 pump - 2 stage with 1 casting housing both cylinders). The 60 gallon model would be their VT-735-60 and 80 gallon variant is their VT-735-80 (splash lube, not pressure lube - I don't think I mentioned that elsewhere, but the subject did come up on my original thread on trying to find a compressor).


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## mksj (Jan 4, 2021)

Still worth looking at if you are in that price range and want higher CFM flow and 7.5 Hp. Supposedly the Baldor motor draws 31A, I still would use a 50A breaker and wire accordingly. They put out 25.8 CFM at 175 PSI, be hard pressed to use more than that as a hobbyist, and the pump is only turning 575 RPM. Supposedly made in the US, but parts come from different places. 








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