Great video! just remember if your readings are on a cold motor it’s going to get worse when it’s under load or hot. Heat expanding the insulation giving you lower M-ohms.
Came across these motors often. Engineers recommended enclosed motors to prevent moisture from entering the winding. Thank you for your educational support
Thanks for posting and keeping it simple. Are you an electrician or hvac Technician? I have the fluke 1520 and you see very few hvac guys with megommeter. I'm hvac Technician myself. Those tradesmen that work on motors will eventually have a misdiagnosis when checking for a short; especially on outdoor motors. Thanks again.
@@TheWpruden I've been an Electrician and HVAC Tech. In the last 20 years I've focused completely on HVAC. The MegOhmer is critical if you do commercial refrigeration. They're worth their weight in gold.
Nice video. Typically we test wiring at 2x the nominal voltage. 480 = 1000v Windings are tested at rated voltages to not over stress the components. The 1507 is nice because you can test as low as 50v.
Thank you for the video. Can you make More video of this kind. Helps seeing other people trouble shooting equipment in different situations. Thank you.
I plan on lots more content in the Spring. I will do a video on the Fluke 1507 and how to use it to reestablish a VFD that has been in storage and some more motor tests. Thanks for watching!
There’s a ‘micro short’ in the windings…meaning…that a conductor in one turn in the winding is actually broken, but when a the motor cools, the conductor is touching and will read fine. When the motor runs, it pulls current and the conductor will heat up and separate, shutting down the motor and tripping the drive. The drive can run on two phases only and typically doesn’t detect the break until the winding heats up.
The meter I bought is Klien Et600 it can test upto 1kv. And it says it's 400mega ohms. Does it mean I will not be able to use it for such motors like this on the video which it's gotta be greater 550m ohms. ?
Thank you for the informative vieeo, some guys says you have to choose double the voltage of the motor on the meter is this acurate and i not sure why they claim this ?
@@xraybravo7180 - Technically he’s correct, but some say one thing and others say something different. I want to know if I have a failure at the Voltage being used by the motor. Doubling the voltage isn’t going tell me anything new. If a motor fails at 1000V it’ll fail at 460V also.
@wtfman5313 how much ohms is bad or going to be bad I bought klien ET600 megger and it doesn't have the range of good and bad values for compressor and motirs.
I had the same issue with a motor that was controlled by a VFD. It would start up and run for a few seconds then when it would get up to maybe 70 percent of the actually full load RPM’s it would trip the VFD. I’m gonna go out on a limb and say after you swapped out the motor the problem was fixed or did you still have issues with the VFD as well?
Well, you're actually testing the winding insulation to case ground so you would ideally want to see an infinite reading. You are checking leakage of current through the wire insulation to the chassis of the motor so you would want as large of a reading as possible in ohms. Minimum resistance of a motor winding will vary widely based turns, wire thickness and such, but on a Meg ohm test of a motor, you want maximum resistance. Hope this helped.
So it test the insulation of the wires but couldn’t you do the same with a fluke multi and test ohms from any of the motor leads to ground and if you have resistance it’s bad right? Just trying to justify buying this
Not always. VFD's are sensitive enough to trip on High current yet when you ohm the motor winding to ground, you get an infinite (OL) reading the majority of time. Your meter may blip and then go to OL (Open Loop). If that's the case, you've found a motor going bad (as long as the motor is disconnected or isolated from the supply.) Many times, you need electrical pressure on the windings to pick leakage current as volt meters don't supply enough voltage to detect.
Yes, the leads were disconnected from the output contactor. No harm would come to the drive as long as the contactor is open - which it is when there is no command for it or the drive is powered off.
@WTF Man! ok good thanks I'm just learning this stuff I think I was confusing it with ohming. So you're checking the insulation of the wires up to the open contacter. I've only done it directly to the motor and I have heard of a drive being smoked this way but the contactor must have been closed.
I guess it depends on the motor manufacture but what values do you consider good? Some say they’re looking for 20-40. over 40 great but start getting concerned around 20. Thanks
By the voltage that is supplied to the motor. In this instance, the motor is a 480 Volt motor so I selected 500V. Any thing over 575 V you would use 1000V.
Hello thanks for the info! I noticed that you have a over voltage fault on your drive is that correct? Is so, what was the solution for that? I have the same problem! Thank you!
Yes please i have that over voltage problem for a few days and is driving me crazy! The motor it was grounded so i will replace that in this next days and see from there if i can do something with that fault! Thanks
@@Jorge_pdll generally the overvoltage error on an Eaton VFD is Bus related and internal to the VFD. Typically I get those errors near the end of a VFD’s service life. That drive has since been replaced.
500 volts not mega ohms. The ideal reading for a 3 phase 480 volt motor that is good would give you a reading of greater than 550 mega ohms on each of the 3 wires at 500 volts.
I did this exact test same meter and got nothing 0 on all 3 legs? Motor was definitely fried smelled it when I removed the pecker head. But what does it mean with 0 on all 3?
Don't know if this is appropriate, but can you name the manufacturer of the air handler? I ask because it looks like a des champs/munters. They also have narrow access doors on some models.
Yes as long as you use the multimeter function of the meter. Any windings shorted together would read zero resistance and you'd get a resistance value between the shorted windings and the un-shorted winding.
Hehe... I have replaced so many Baldor's over nearly 40 years! The shaft bearing seals bleed and grease gets into the gap between the rotor and stator and creates a path... If you look at that motor case, you'll see what I mean.
So a high ohm reading on the feeder wires means the wires are good? And a low reading would mean it shorted or something? What does it mean when there’s a low reading like that for the motor wires?
You want to ideally read infinite when reading your windings, leads or current carrying device. Shorts will give you a very low reading such as .1 or 0 ohms. There are a few exceptions though, but they apply to electronic devices mostly. You are correct.
I’m looking for a new meter, I do industrial maintenance. I interact mostly with 3 phase motors 30hp and smaller. I have always seen the value in a megger but none of the shops I’ve worked in have them. Considering the 1587 as it should have all the features of an 87v or plus able to meg out motors. Would I be able to test these motors reliably or do you need a dedicated megger?
Typically, a Fluke 87 or equivalent (I use the 179) would be fine to diagnose a faulted motor. Example: testing a winding to it's case or a ground may blip your screen very briefly then show infinity again. That is a motor with failing windings. The 1587 is to test the winding insulation and should be part of an annual maintenance action or to verify whether a motor is causing a VFD or other current monitoring device to show a fault due to leakage to ground. Other than that a regular Fluke model volt / ohm meter is what I usually go to.
Great video! just remember if your readings are on a cold motor it’s going to get worse when it’s under load or hot. Heat expanding the insulation giving you lower M-ohms.
Came across these motors often. Engineers recommended enclosed motors to prevent moisture from entering the winding. Thank you for your educational support
Thanks for video. I think you did the most basic but best way of understanding the megging of a motor.
Thanks for posting and keeping it simple.
Are you an electrician or hvac Technician?
I have the fluke 1520 and you see very few hvac guys with megommeter. I'm hvac Technician myself.
Those tradesmen that work on motors will eventually have a misdiagnosis when checking for a short; especially on outdoor motors.
Thanks again.
@@TheWpruden I've been an Electrician and HVAC Tech. In the last 20 years I've focused completely on HVAC. The MegOhmer is critical if you do commercial refrigeration. They're worth their weight in gold.
Had to replace a couple of those in the air makeup units at work. They’re about 230lbs. Fun times
Nice video.
Typically we test wiring at 2x the nominal voltage. 480 = 1000v
Windings are tested at rated voltages to not over stress the components.
The 1507 is nice because you can test as low as 50v.
Where does that come from and what's correct on the book?
No music! Great vid!
@@chancesmith1141 Thank you
Great video bud!
Thanks man!
Thank you for the video. Can you make More video of this kind. Helps seeing other people trouble shooting equipment in different situations. Thank you.
I plan on lots more content in the Spring. I will do a video on the Fluke 1507 and how to use it to reestablish a VFD that has been in storage and some more motor tests. Thanks for watching!
Wonderful Instruction. Thank you.
Thank you for taking the time to watch!
There’s a ‘micro short’ in the windings…meaning…that a conductor in one turn in the winding is actually broken, but when a the motor cools, the conductor is touching and will read fine. When the motor runs, it pulls current and the conductor will heat up and separate, shutting down the motor and tripping the drive. The drive can run on two phases only and typically doesn’t detect the break until the winding heats up.
You rock my dude 😎🤘
Right back at ya!
What reading would you get if you megger between the windings if the motor is bad? ( T1 to T2 ) ..etc
You said the other windings “had”to read the same as the first bad one you tested..why? Because it’s shorted across the windings?
I usually get out my multimeter and test resistance between coils. Any variance tells me motor is bad. This tool is too fancy for me 😂
Sometimes you don’t get that blip on the meter. This was to verify or condemn a suspected VFD that turned out to be a failing -not failed yet- motor.
The meter I bought is Klien Et600 it can test upto 1kv. And it says it's 400mega ohms. Does it mean I will not be able to use it for such motors like this on the video which it's gotta be greater 550m ohms. ?
That meter will work just fine. If I had to purchase my own meter, that's the one I'd get.
@wtfman5313 so mow I need to know at what ohm insulation test compressor or motor is in danger zone and what ohm it's bad ?
Thank you for the informative vieeo, some guys says you have to choose double the voltage of the motor on the meter is this acurate and i not sure why they claim this ?
@@xraybravo7180 - Technically he’s correct, but some say one thing and others say something different. I want to know if I have a failure at the Voltage being used by the motor. Doubling the voltage isn’t going tell me anything new. If a motor fails at 1000V it’ll fail at 460V also.
@wtfman5313 how much ohms is bad or going to be bad I bought klien ET600 megger and it doesn't have the range of good and bad values for compressor and motirs.
I had the same issue with a motor that was controlled by a VFD. It would start up and run for a few seconds then when it would get up to maybe 70 percent of the actually full load RPM’s it would trip the VFD. I’m gonna go out on a limb and say after you swapped out the motor the problem was fixed or did you still have issues with the VFD as well?
The problem was fixed. The new motor has run without issue since that day. Install of the new motor was the same day.
@@wtfman5313 Good to know! Thank you for the video and keep up the good work brotha!
What is minimum resistance reading for insulation test, so we can say that component can use
Well, you're actually testing the winding insulation to case ground so you would ideally want to see an infinite reading. You are checking leakage of current through the wire insulation to the chassis of the motor so you would want as large of a reading as possible in ohms.
Minimum resistance of a motor winding will vary widely based turns, wire thickness and such, but on a Meg ohm test of a motor, you want maximum resistance. Hope this helped.
What would have been a good reading? If the motor was fine
> 500 Meg Ohm @ the 500V setting for a 480V motor.
So it test the insulation of the wires but couldn’t you do the same with a fluke multi and test ohms from any of the motor leads to ground and if you have resistance it’s bad right? Just trying to justify buying this
Not always. VFD's are sensitive enough to trip on High current yet when you ohm the motor winding to ground, you get an infinite (OL) reading the majority of time. Your meter may blip and then go to OL (Open Loop). If that's the case, you've found a motor going bad (as long as the motor is disconnected or isolated from the supply.) Many times, you need electrical pressure on the windings to pick leakage current as volt meters don't supply enough voltage to detect.
Okay thanks man that’s exactly what I thought so I could technically miss a bad motor using just my fluke multi meter
Does the same apply to just testing wires is a multi meter suffice enough using the ohm setting to see if you wire is compromised
@@austenkeller1247 yes. A multi meter is good for that.
I need to get a megaohmeter, should i get the insulation tester or just regular meter ?
@@xraybravo7180 A regular Volt Ohm meter won’t do insulation testing.
@wtfman5313 whats bad insulation resistance ohm on motor and compressors general rule ?
did you disconnect the leads at the VFD? wouldn't that fry the drive if you didn't?
Yes, the leads were disconnected from the output contactor. No harm would come to the drive as long as the contactor is open - which it is when there is no command for it or the drive is powered off.
@WTF Man! ok good thanks I'm just learning this stuff I think I was confusing it with ohming. So you're checking the insulation of the wires up to the open contacter. I've only done it directly to the motor and I have heard of a drive being smoked this way but the contactor must have been closed.
Great video. Its nice to see it done instead of just reading about it. Did you rewind it afterwards or replace it?
We wound up replacing it. The Baldor rolled steel motors aren't worth the cost to rewind.
Excelente
Thanks for sharing New
could it be contaminated inside with dirt and dust, Possibly conductive dust.
@@bobbauvian7700 I’ve never seen dry material do that to an electric motor.
How did you get on with the over all issue?. Was the drive faulty?
The drive was good. Just a bad motor.
I guess it depends on the motor manufacture but what values do you consider good?
Some say they’re looking for 20-40. over 40 great but start getting concerned around 20.
Thanks
only has to be above 1M ohm in australia depends on standards
I want to learn how to do this. 😕
Do you leave the wires terminated on the VFD when testing?
Yes. The wires were not connected at the VFD or the motor. They're completely isolated for testing.
Is that to check if you have a break in the wires leading to the vfd? but the ground was connected to the vfd to complete the circuit?
I'm also wondering the same here
How do you know what value to set the megger to?
By the voltage that is supplied to the motor. In this instance, the motor is a 480 Volt motor so I selected 500V. Any thing over 575 V you would use 1000V.
@@wtfman5313 gotcha thank you!
Meaning0 the set range of the actual value must be high higher to idenity if it good or bad?
Nope, not so. Not according to FLuke.
Hello thanks for the info! I noticed that you have a over voltage fault on your drive is that correct? Is so, what was the solution for that? I have the same problem! Thank you!
The problem will be with your drive or less likely, main power feed to the drive. I will eventually post a vid on how to find out.
Yes please i have that over voltage problem for a few days and is driving me crazy! The motor it was grounded so i will replace that in this next days and see from there if i can do something with that fault! Thanks
@@Jorge_pdll generally the overvoltage error on an Eaton VFD is Bus related and internal to the VFD. Typically I get those errors near the end of a VFD’s service life. That drive has since been replaced.
@@Jorge_pdll The fault if you don’t already know is an internal bus fault. You can replace it or send it to a service center.
Whe do u test for more than 500mega ohms and 100 mega ohms
Rephrase your question. I'm not sure what you're asking?
How come you chose to test the motor at 500MO? And did u test every single phase lead of the motor? Thank u
@@oscar27ization he tested it at 500 volts and the meter indicated the resistance was 500 MO
500 volts not mega ohms. The ideal reading for a 3 phase 480 volt motor that is good would give you a reading of greater than 550 mega ohms on each of the 3 wires at 500 volts.
What kind of VFD? Danfoss i suppose
I did this exact test same meter and got nothing 0 on all 3 legs? Motor was definitely fried smelled it when I removed the pecker head. But what does it mean with 0 on all 3?
It’s shorted to something internally in the motor causing 0 ohms of resistance - which is a short circuit. All legs are touching the case.
Don't know if this is appropriate, but can you name the manufacturer of the air handler? I ask because it looks like a des champs/munters. They also have narrow access doors on some models.
It’s a 150Ton “Seasons 4” chilled water AHU. I believe they’re made in Atlanta, Ga.
@@wtfman5313 Thanks friend. I had a 60 hp go out a bit ago on a munters unit. Ridiculous the things these manufacturers squeeze into some those units.
Have u ever seen a motor running while also having resistance to ground ? I found one with 4 ohms to ground on T1/T2/T3
yeah,
ive also seen one, what i think is that the current leaked to the ground is not high enough to trip the MCB or trigger the VFD short circuit
@@chefeatsher I have seen this on both single and three phase. Pretty cool actually.
this video made me lose braincells
Can this identify turn to turn faults?
Yes as long as you use the multimeter function of the meter. Any windings shorted together would read zero resistance and you'd get a resistance value between the shorted windings and the un-shorted winding.
Its a balder motor... Of course it's good...
Hehe... I have replaced so many Baldor's over nearly 40 years! The shaft bearing seals bleed and grease gets into the gap between the rotor and stator and creates a path... If you look at that motor case, you'll see what I mean.
So a high ohm reading on the feeder wires means the wires are good? And a low reading would mean it shorted or something? What does it mean when there’s a low reading like that for the motor wires?
You want to ideally read infinite when reading your windings, leads or current carrying device. Shorts will give you a very low reading such as .1 or 0 ohms. There are a few exceptions though, but they apply to electronic devices mostly. You are correct.
I’m looking for a new meter, I do industrial maintenance. I interact mostly with 3 phase motors 30hp and smaller.
I have always seen the value in a megger but none of the shops I’ve worked in have them. Considering the 1587 as it should have all the features of an 87v or plus able to meg out motors. Would I be able to test these motors reliably or do you need a dedicated megger?
Typically, a Fluke 87 or equivalent (I use the 179) would be fine to diagnose a faulted motor. Example: testing a winding to it's case or a ground may blip your screen very briefly then show infinity again. That is a motor with failing windings. The 1587 is to test the winding insulation and should be part of an annual maintenance action or to verify whether a motor is causing a VFD or other current monitoring device to show a fault due to leakage to ground. Other than that a regular Fluke model volt / ohm meter is what I usually go to.
Hh
Hello my dear new friend your a good electrician.. watching from philippines...👇👇👇👇👇🤝🙏🏼
Thank you! I have more coming in the Spring so stay tuned.