# PM-949V - need 3 HP motor specs



## mikey553 (Dec 29, 2017)

I am setting up the VFD to drive the 3 phase motor on my mill. For that I need to know the motor full load amps (FLA). Unfortunately my motor nameplate is not stamped correctly. It shows 6.2A for 220V. 3 HP motor should have higher FLA. Matt assured me that I have a 3 HP motor, just the nameplate is misstamped. Variable speed heads for 949 mills always come with 3 HP motors. Amps data stamped apparently came from a higher voltage motor. 

Anybody has a similar 3 HP motor? Would you mind telling me what your FLA is for 220V supply? Your help will be greatly appreciated.

By the way, this motor is of open design. It sucks the air from above the motor, routes it around motor coils and blows it out of belt housing vents. This may explain how they could build such a light weight but powerful motor. It weighs only 52.6 lb complete with pulleys. Need to remember to put some fine mesh wire cloth over the motor top to protect the motor.
Since I took the mill apart for moving I weighted all major components. If anybody needs the weight data, let me know.


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## mksj (Dec 29, 2017)

I would set the VFD up according to the motor nameplate and allow a 150% overload setting which is fairly typical. Many VFDs you set the kW setting and not the amps. Below is a newer 949 motor which species 8 amps for 3 Hp, but it is a constant Hp dual speed motor. You rarely use anything near the full Hp rating of a mill motor in a hobbyist setting, so using the 6.2A with the higher overload should work OK and not but your motor at risk. I doubt that the nameplate is wrong, but even if the motor was 100% efficient, 3Hp works out to something like 7 amps. Often, it seems like Asian motors are a bit optimistic as to Hp  relative to the motor frame size.


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## Robert LaLonde (Dec 29, 2017)

Amps * volts = watts 

Watts / Volts = Amps

750 watts apx is 1 HP.  Most guys figure 800 watts per real horsepower with various losses due to heat parasitic load etc.  

3 X 800 = 2400 Watts  (PEAK AT ON A FULLY LOADED MOTOR)

2400/220=10.91 amps

However, you likely have between 230 and 240 actual voltage. So instead figure  
2400/240=10.0 amps

******  ALERT KEEP READING ******

All of that would be well and good if we were talking about a single phase motor, but we are not.  We are talking about a 3 phase motor, and you have amps per phase.  The amps per phase for a 3 phase motor of the same size will be much less than the amps per phase for the same size single phase motor.  Look at the table on this page:  https://www.engineeringtoolbox.com/ampere-phase-d_449.html 

Scrolls down to where it shows a 10.4 amp load on single phase 240, and then look over to the 3 phase amps per phase rating on the same line.  

6.1 amps.  Amazing.  Very close to what your motor plate says.  Add in the factors I mentioned and you are probably dead on.


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## Clock work (Dec 29, 2017)

[QUOTE="Anybody has a similar 3 HP motor? Would you mind telling me what your FLA is for 220V supply? Your help will be greatly appreciated.

By the way, this motor is of open design. It sucks the air from above the motor, routes it around motor coils and blows it out of belt housing vents. This may explain how they could build such a light weight but powerful motor. It weighs only 52.6 lb complete with pulleys. Need to remember to put some fine mesh wire cloth over the motor top to protect the motor.
Since I took the mill apart for moving I weighted all major components. If anybody needs the weight data, let me know.[/QUOTE]


Here's the plate from my 935, also 3hp:  


__
		https://flic.kr/p/SYJ8PC

Based upon a printout of my VFD parameter decisions, I set the FLA  to 8.5A during VFD setup. 

This shows the casing for my 3hp motor... it does look different:


__
		https://flic.kr/p/21yvvpu

I forget the name of that casing style but there is one. I also recall I was able to track down the motor manufacturer's web site to seek out additional info on winding insulation but I do not seem to be able to put my hands on that link... I probably no longer have it but it would be, IMO, worthwhile to take a look. Good luck.


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## mikey553 (Dec 29, 2017)

A typical brand name 3 HP 3 phase motor has FLA of 7.8-8.8A. This came from the actual industrial motors I have seen. This is not from a book, web site or from my imagination. 3 HP on American nameplate means the mechanical power on the motor shaft end, available to the user. It is not the VA power motor pulls from the grid.

I agree the Chinese motor manufacturers are a bit optimistic about many things, horsepower included. Mksj, I can barely see from your picture, but it looks like your motor is 2 poles, 3 HP and weighs 30 kg. My nameplate shows 4 poles, 3 HP and 24 kg. Being 4 poles my motor should be bigger than yours with the same horsepower. 
Anybody has a motor similar to mine?


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## mikey553 (Dec 29, 2017)

Thank you Clock work for your reply. 8.5 A is right on the money for 3 HP motor. Your motor is most likely of TEFC (totally enclosed fan cooled) design. Still the question stands - do I have a 3 HP motor or not? Also what is the correct FLA for my motor?


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## Robert LaLonde (Dec 29, 2017)

Actually I've often found cheaper Chinese motors are rated at stall.


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## Bob Korves (Dec 29, 2017)

Chinese horsepower is different than USA horsepower:


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## mksj (Dec 29, 2017)

The motor shown is for a PM 949 (pictures from are from the owner of the mill) it is both a 2 and 4 pole motor rated at constant Hp on either winding. It lists 8.5A on 2 pole and 8.0 on 4 pole, the nameplate states a motor weight of 30Kg. It is a TENV, so fairly substantial. I also have a Taiwanese 3Hp VFD motor on my knee mill which is a TEBC, the nameplate is 8.0A at 220V.  As I stated, I would set the VFD to the motor nameplate amperage and dial up the overload, I seriously doubt that the nameplate would be in error, but whatever. Please also note that some motors may be rated at 2Hp for continuous duty and 3Hp for shorter time frames, which may be the case here.


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## mikey553 (Dec 29, 2017)

Horsepower or FLA is all about how efficiently you can cool the motor. My motor being of open frame type can be cooled better than an enclosed frame motor. The cooling air can directly flow over the coils. This could be why this light motor can still develop 3 HP and not overheat. After all Matt guaranteed the motor is 3 HP. I even remember the email from the manufacturer sent to me by Matt, where they said the nameplate was misstamped.

If you ever heard about hermetic refrigeration motors, it is amazing how much power can they pack in a small frame. For example a 200 HP hermetic motor would weigh about 150 lb - way less than a regular motor of such power. This is because such motors are refrigerant cooled, which is a very effective way of removing the heat.


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## Clock work (Dec 29, 2017)

mikey553 said:


> Thank you Clock work for your reply. 8.5 A is right on the money for 3 HP motor. Your motor is most likely of TEFC (totally enclosed fan cooled) design. Still the question stands - do I have a 3 HP motor or not? Also what is the correct FLA for my motor?



That was the term. Thank you. You're welcome and apologies that I wasn't able to answer your question... I tried to give you a path to dig beyond forums. I'm pretty down on forums (and YT and other hyper-diluted internet-based fountains of trustable information and known best methods. I'm so far beyond the fact-gathering stage for my VFD design that I can't provide any useful details other than... I have a clear recollection of not being able to nail down everything I was looking for, and I had to triangulate in to an improved estimate  rather than a nailed down fact. 

I thought I had a pile of fairly decent industry/practitioner-grade app notes on electric motors and standards but I'm not finding those at the moment. If the plate is suspect, you either have to establish its correctness via an alternative method or swap motors. I'll say this... they come off easy and that'd be what I insist upon if there were not a *guaranteed* alternative method to which all parties agree. You didn't create the situation so you get the final veto IMO. Can you ascertain anything from the wire gage/stranding/marking? I can think up an experimental way to get there but I don't you can just do V*I*eff because eff comes off the plate and the plate is suspect. You'd have to measure power out. Doable.. PITA. Is there a SN stamped on the case rather than the plate and if so can you work anything back from that? If the plate is actually right, you have the wrong motor. If the plate is not right or might not be, you have uncertainty that is hard to eliminate conclusively. Sorry I can't be more than useless. Tough situation. Good luck.


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## mksj (Dec 29, 2017)

News to me that your motor draws less because it is air over coils. Your motor is not more efficient due to cooling, just lighter. The motor design and construction dictate efficincy, larger Hp motors are more efficient then smaller Hp. We have provided you with a range 0f FLA for mills with 3Hp motors. Maybe put a water cooled motor on it if you want to believe something else. If you were informed that the nameplate is incorrect then ask them to provide the correct information for your specific motor.  Does the VFD require FLA or kW, as mentioned most VFDs are based on kW, not FLA which makes all this moot. The only other 3 Hp mill motors that I have seen with a FLA of around 6.6A is Bridgeport with a 2Hp motor and rated for 3Hp for something like 45 minutes.


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## Clock work (Dec 30, 2017)

I think where Mikey553 was coming from was bringing thinking from farther up the motor-design/implementation pipeline... specifically service life. In concert with the bearing life, the leading determinant of the end of service life is an insulation breakdown and that is predominantly an effect from the accumulated exposure to excess heat, and current plays a very large role in that. So, the designer/manufacturer (under the "requirements and guarantees philosophy") will specify a current limit... and it's not like they're pulling this stuff out of thin air (thank God given the clueless 20-something idiots I was interviewing when I "got bored" with my company) as there are standards of practice and margins that people have figured out over time don't drive your warranty costs or reputation into the crapper. And from current and the voltage coming out of the wall/VFD, we have Power-in. I think he may have been recognizing the path from heat effects to HP spec, albeit assuming the world followed his crappy lecture (show all your work Mikey553!!! Forums do not grant partial credit.. 

Just a comment on the FLA/kW thingy. What a computer interface requests of you is that designer's responsibility... not the user's. Give the ROOM FULL of IDIOTS I used to own... I mean... employ... yea... employ, to execute/implement very sophisticated tools, I must assure you with more sincerity than I could muster about the sun rising tomorrow... it is extremely reasonable that he is seeing an FLA parameter. The idiots who design things FREQUENTLY don't "get" crap about its function... or ANYTHING about the usage model... of the thing they're designing. You need a smart guy somewhere in the company for that who isn't going to get sick of fixing the same raging-idiot mistakes from the same guys for 30 years and they're a very very endangered species. The UI and usage model and documentation of my VFD made me want to get my passport and go on a killing rampage in my favorite Asian country. In cause/effect space, I agree that the simplest expression of motor parameter determination (what all that code in the VFD is doing) is kW. But current coupled with a knowledge of supply voltage and the motor efficiency gets the job done too. I am not quite sure what that "optimization routine" that I could specify for my VFD does but I suspect one reasonable choice was to produce an estimate of efficiency. Again.. sub optimal without measuring torque-out but I could see a white board in Japan somewhere with a development on it for a ballpark estimation. Or not. I'm guessing at that... could easily be off. But on the design stuff... I probably haven't forgotten too much of that. Yet. 

I stand by my suggestion that the core obstacle to resolving the issue is resolving the uncertainty to the satisfaction of the customer. Improved estimates might be possible but if the plate is wrong, I'd only clear that up one way.. a proper motor. I remove/install... manufacturer ships both. 

Take care.


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## mikey553 (Jan 2, 2018)

Sorry about a delay in my response. We had to go north to see our two lovely granddaughters over the holidays.

I have actually found a response from the mill factory (sent to me by Matt). Here it is.

_"Hello Friend
thanks for your email.
please send the infomration of new order.thanks about new motor plate, is our works that stamp the universal motor plate for cutsomer power. it is mistaked, please let them to fix it, hp correct, but stamp 380/575V amp rate. so amp rate 220/440V 8.8/4.4 amp is proper. 2.2KW=3 hp. works not maked 2hp variable motor. only step spindle 2hp motor."_

I do not know about you, but such answer does not inspire a lot of confidence in me. Let me translate it for you. The mill assembly factory receives motors from some other place without nameplates. Than they stamp whatever information they think is appropriate for each case on the nameplate and attach it to the motor. Very nice process...

So they suggest in my case FLA should be 8.8A (for 220V supply). I can input this data into my Hitachi WJ200 VFD and hope for the best. But I think you would not blame me for not trusting the manufacturer anymore and wanting some other confirmation. I was hoping to get it from you guys.



mksj said:


> News to me that your motor draws less because it is air over coils.


I have never said that. All I said was that ODP motor can be cooled very efficiently and therefore may have a relatively small size and weight.

Still waiting for somebody with the same motor as mine...


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## qualitymachinetools (Jan 5, 2018)

Same as I said before in your other post saying that you had a problem with the newspaper and casting, I said we would take care of whatever you needed, but you never contacted us. If there is anything wrong, we would not leave anyone hanging. 

    The serial plate on that motor is dated from 6 years ago, I have one on the shelf as an old stock part but in single phase, and there is no nameplate on it at all.  
 A lot has changed in the last 5-10 years too.

I do have one picture that I found from digging through old photos of a similar nameplate, but this one is not dual voltage 

I have plenty of pictures of older machines, but nothing where I could even come close to reading the name plate. Sure is amazing how far cameras have some in the last 10 years. Looking at these pictures from 2008. Can't believe that was 10 years ago already


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## mksj (Jan 5, 2018)

Having done numerous installs with the Hitachi WJ200 and other VFDs, the basic WJ200 motor parameter for a 3Hp motor is set by H003 which would be 2.2 kW. The default factory overload restriction level B022 is set to 150%. Which means that the WJ200 VFD can provide up to 150% current overload for up to 1 minute. This is fairly typical, but if one was worried about the motor, one could decrease this to 120% which is fairly common level for other brands of VFDs. I access the WJ200 programming via USB/computer which shows this as %, but my understanding is that direct access programming via the WJ200 front panel this shows up as amps. If so, then I would suggest that you use the nameplate motor amps 6.2 x 1.5 (so 9.3 amps) for this parameter. Even if the motor name plate was incorrect, this overload point would be very similar to what other VFDs use, so if an 8 amp motor x 1.2 ( 9.5 amps).  My only other suggestion would be to measure the motor current in operation and extrapolate from there or compare to another motor of the same capacity. I have seen a wide variation on current draw for similar 3 phase motors of the same Hp, so my 2 Hp Taiwanese lathe motor states 6.6 amps and my replacement Baldor inverter motor states 5.4 amps. When I replaced the stock motor, I left the motor kW and overload parameters the same.


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## qualitymachinetools (Jan 5, 2018)

mksj is an excellent source of information, I understand motors and VFD's, but not like him! I Highly recommend anything that he says.


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