# 2 Motors enter, only one Motor leaves the octagon!



## EtexTech (Jun 20, 2015)

I've been troubleshooting a pump skid with Leeson motors on the pumps, these motors have been running too hot, and the VFD has been throwing an overtemp fault. I've got steady voltage and amps going into the drive, and at the drive output, all three legs at drive output read identical. Drive settings match the motor specs.

I had access to some spare motors on a very similar skid, which are WEG motors, with VERY similar specs (Really the power factor being 74 instead of 62 is the only difference I can see). Installed the WEG motors, fired it up, no problems. The Leeson motors were wired up correctly, although I did notice they had smaller gauge motor leads than the WEG's. I'd really like to know what the deal is, because just by looking at the motor plates, these Leeson motors are nearly identical specs to the WEG's.

Leeson Motor readings:

20Hz, 144VAC, 1.5A

WEG Motor Readings:

20Hz, 146VAC, 0.9A

These are just standard 3 phase, 208-230/460, 1/2HP motors, 1.9-2/1 FLA.
The amps on the Leeson motors never read less than 1.0A even down to 10hz drive output (Min dosage setting for our application) and got up to 1.8A at 50Hz. Any thoughts aside from just chunking them and going with WEG's?


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## MDShunk (Jan 7, 2007)

As I recall, the WEG motor field coil housing is a finned radiator of sorts, so it will run cooler. 

Is this the difference, perhaps, between a Leeson TENV motor and a WEG TEFC motor? That's huge. I'd really like to see the full dataplate on both motors. 

Where's your overtemp fault generated? Is the drive itself going overtemp, or do you have a thermistor or something in that little wee motor?


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## Southeast Power (Jan 18, 2009)

Is this a new problem or is this a start up?
What is the over temp?
What are the environmental conditions?


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## JRaef (Mar 23, 2009)

MDShunk said:


> As I recall, the WEG motor field coil housing is a finned radiator of sorts, so it will run cooler.
> 
> Is this the difference, perhaps, between a Leeson TENV motor and a WEG TEFC motor? That's huge. I'd really like to see the full dataplate on both motors.
> 
> Where's your overtemp fault generated? Is the drive itself going overtemp, or do you have a thermistor or something in that little wee motor?


I agree, the voltage and current are not the only considerations. If the leeson motors are TEFC, the "FC" means Fan Cooled, so the motor REQUIRES the fan in order to stay cool. At 20Hz, the fan performance curve may result in almost no cooling effect from it. But if the WEG motors are TENV, the "NV" means Non Vented", so the motor is DESIGNED to operate with no fans at all, the cooling takes place through the fins on the frame and the rotor shaft. So without that info, we don't know if you are comparing apples and oranges here.

Also, the efficiency rating of the motor makes a difference, because if the Leeson motors have a lower efficiency rating, that lower efficiency means more heat losses in the motor.


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## John Valdes (May 17, 2007)

I also ask for the frame type for each motor.
Rolled steel? Cast iron? Fan cooled (TEFC) or TENV?

Inherently rolled steel frames do run hotter. They have to. Heats gotta go somewhere.


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## JRaef (Mar 23, 2009)

By the way, love the Mad Max reference...


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## EtexTech (Jun 20, 2015)

Its an Eaton drive, that provides the over temp protection by using the drive temp as a reference, as well as the changes in motor current compared to motor data entered into the drive during the commissioning phase. There are separate faults for motor over temp and drive over temp, and for over current for both as well. I admit that is about as much as I know about it at this point, and I might not even understand that much correctly. This is a start up application, environmental conditions are not bad, but the drive panels are not vented or cooled, and we haven't had any drive issues due to heat on any other skids. Not sure what would be considered the actual over temp threshold.

WEG motor data plate info:

3PH 1/2HP V208-230/260 DES-A, A 1.65-1.6/0.80 60Hz, 1750 RPM CODE-L
TYPE-ET, TEFC, SF 1.15 CONT DUTY EFF % 77 AMB 40C 1.0 SF @ 208V PF 0.74
INS F DeltaT 80k FR B56C


Leeson Motor specs:

3PH 1/2HP V208-230/460 F.L.A. 1.9-2/1 S.F.A. 2.1-2.2/1.1 SF 1.15 1725 RPM 60Hz
INS B3 AMB 40C CONT DUTY Code L Design B EFF% 73 PF 62

FR S56C And this one actually says not thermally protected.

Looks like rolled steel cases on both, I've made suggestions to the supplier of these skids to work on venting/cooling these panels, but they really don't get that hot, they are inside, and the panels are plastic.

The supplier/manufacturer suggested changing the motor amps setting in the drive from 1.9 to 2.2, I advised against this, but went along with their request mainly because they confirmed they will eat the cost of new motors when these go Chernobyl lol. 

Sorry for the late reply, and I appreciate all the input, I know you guys are busy as well, and I'm thankful for your time. Been in a 9 line bind around here for a while, and probably will be that way till the end of summer. Thanks again and stay safe.


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## EtexTech (Jun 20, 2015)

And most time I feel like I'm in the thunderdome lol


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## Jlarson (Jun 28, 2009)

EtexTech said:


> WEG motor data plate info:
> 
> 3PH 1/2HP V208-230/260 DES-A, A 1.65-1.6/0.80 60Hz, 1750 RPM CODE-L
> TYPE-ET, TEFC, SF 1.15 CONT DUTY EFF % 77 AMB 40C 1.0 SF @ 208V PF 0.74
> ...


You didn't list the enclosure type on the Leeson.


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## chicken steve (Mar 22, 2011)

I would consider simply opening the doors on it's _drive panel_ for the sake of assessment EtexTech

~CS~


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## JRaef (Mar 23, 2009)

EtexTech said:


> Its an Eaton drive, that provides the over temp protection by using the drive temp as a reference, as well as the changes in motor current compared to motor data entered into the drive during the commissioning phase. There are separate faults for motor over temp and drive over temp, and for over current for both as well. I admit that is about as much as I know about it at this point, and I might not even understand that much correctly. This is a start up application, environmental conditions are not bad, but the drive panels are not vented or cooled, and we haven't had any drive issues due to heat on any other skids. Not sure what would be considered the actual over temp threshold.
> 
> WEG motor data plate info:
> 
> ...


The motor manufacturers' data sheets will tell you that you CANNOT use the Service Factor on a motor driven by a VFD. Doing so will void the warranty. Make sure you inform the end user of the consequences of that choice.


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## EtexTech (Jun 20, 2015)

The Leeson Motors are TEFC as well Jlarson, and they are running damn hot right now, but still running. Thanks for the tip as well JRaef, that doesn't concern us as much, the skid manufacturer will cover replacement costs evidently. Steve I've been keeping a log of drive data, everything drive side is fine as well. I guess from what you all have mentioned already, the lower efficiency and power factor, are causing this motor to pull a few more amps than usual with this particular application. One of the funny parts to me is, this Leeson motor has a Energy Saving sticker in bold letters on the side.


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## RSmike (Jul 31, 2008)

Some folks were hitting on this but didn't quite come out and say it...Are the motors rated for inverter use? 

RSlater,
RSmike


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## MDShunk (Jan 7, 2007)

RSmike said:


> Some folks were hitting on this but didn't quite come out and say it...Are the motors rated for inverter use?
> 
> RSlater,
> RSmike


Although there are differences in construction, whether a motor is rated "inverter duty" or not is among my last concerns. I've connected old open frame Westinghouse motors from the 1920s on VFD's back in the late 90's, and they're still running today. The way I figure, is that if you need a drive on your application, and you feel the need to replace the motor, why not get the final life out of your existing motor... however much that turns out to be. Naturally, if downtime isn't tolerated, then the more conservative approach is mandated.


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## RSmike (Jul 31, 2008)

I agree with you MDShunk... there is certainly something to be said for they don't make them like they used to. I've seen older motors lasting much longer and be able to take more of a beating than some of the newest motors with all their fancy ratings and stickers...

In our facility we have motors that have operated over 30 years with no issues...running almost 24 x5. We have motors that are only seven years old on newer equipment that are eating bearings/failing in one way or another after only 7 years in the same applications. And this is "normal"....per the motor manufacturer.

Reminds me of a story where the local PoCo in my hometown area tore apart a small 6MW machine at the hydro-station. It was built in the 1930s. They assumed the bearings and such needed to be replaced, repacked, etc. (I stood in the control room while it was being retrofitted. One half looked like the latest and greatest while the other half was full of giant open knife switches and fuses. Crazy! ) Anyway after getting into the rotational portions of the machine they found that the bearings and races were like new....they put everything back together and walked away...(that's the story they told us) It's still going today. Pretty cool stuff. If you are bored..... I even found a link to bit of history on it. http://www.coppercountry.com/VictoriaDam.php

Sorry to get off the topic.

RSlater,
RSmike


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## EtexTech (Jun 20, 2015)

Both the WEG and the Leeson are General Purpose motors. I'm totally fine with these motors burning up, it's no cost to me, it will prove my point to the skid manufacturer and management, and really these are about as easy to change out as it gets. It's just frustrating having to deal with this on a system that's fresh from the manufacturer. We've just installed two other skids identical to this one aside from motor brand, and they have worked flawlessly. 

It's a chemical injection system, pumping from a tote, into an injection line against 200 psi. It's got start/stop reference from a make-up valve position, pump stroke is a mechanical adjustment on the pump (pump is rated for 800psi), and drive output is controlled via a rheostat dial on the face of the panel. All the automated functions can but turned to manual mode. It's a simple system to be sure, just wonder why these Leeson motors pull so many amps. I may ever know (shrug).

I've been going through the drive programming, and haven't found any discrepancies yet. Maybe I can increase the carrier frequency and see if this helps? I'm not even close to stressing this drive as it stands, any thoughts on that?

I'll see if I can put some pictures up soon.


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