# Phase rotation meter



## jeepman (Jan 2, 2013)

Looking for a good phase rotation meter. Seen some flukes. What's your suggestions?


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## Bbsound (Dec 16, 2011)

we have had good luck with the AEMC


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## wildleg (Apr 12, 2009)

I use a hioki with the on-contact amp clamps (wraps around 500's). It's a little piece of junk, but inexpensive and works like a champ.

http://www.bonanza.com/listings/Hioki-3129-10-Phase-Rotation-Meter-with-large-jaw-clamp/121749291?gpid=41917063381&gpkwd=&goog_pla=1&gclid=CNK6o9z8wLkCFao7Ogod114AaA


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## Lone Crapshooter (Nov 8, 2008)

I have used a Knopp for years. Never had a problem

http://www.knoppinc.com/phase_seq.htm

LC


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## fanelle (Nov 27, 2011)

I have the fluke. Its nice but I also bought an ideal so I could do motor rotation also. It comes in handy if you do a lot of motor work.


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## Big John (May 23, 2010)

wildleg said:


> I use a hioki with the on-contact amp clamps (wraps around 500's). It's a little piece of junk, but inexpensive and works like a champ.


 Does that actually need current flow to get a reading, or can you connect it to the line side of an open switch and get rotation?

Why do you say it's junk?


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## Bbsound (Dec 16, 2011)

Lone Crapshooter said:


> I have used a Knopp for years. Never had a problem
> 
> http://www.knoppinc.com/phase_seq.htm
> 
> LC


Good meters, but six times the price of the AEMC


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## Big John (May 23, 2010)

And what I've got is a PSMR1 from UEI which will do phase sequence and motor rotation. I think it cost about $70.


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## wildleg (Apr 12, 2009)

Big John said:


> Does that actually need current flow to get a reading, or can you connect it to the line side of an open switch and get rotation?
> 
> Why do you say it's junk?


It acts like a little toy car motor, for all I know that's what's in it. So just makes me think junk, as opposed to "cadillac".

I know I've check rotation with no current flow, but now you bring it up, I'm confused as to how it works.


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## SteveBayshore (Apr 7, 2013)

Big John said:


> Does that actually need current flow to get a reading, or can you connect it to the line side of an open switch and get rotation?


No current needed for Hioki meter, works on voltage presence. Bought one a couple of years ago because I had a customer in a machine shop that I was relocating, mark rotation on about 90 machines before I started the project. I didn't want his "maintenance" guy working with hot alligator clips. Once I used it myself, I put my other phase sequencers back in the shop.:thumbsup::thumbsup:


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## Lone Crapshooter (Nov 8, 2008)

The reason I went with a Knopp is when I was working in Freeport TX I worked a contractor that had a large line crew. Those guys could tare the horn off a anvil. I think that comes with being a lineman.
They used Knopp phase rotation testers and they seem to last for the linemen. So I knew a Knopp would work me.

LC


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## gotshokd666 (Oct 17, 2012)

fanelle said:


> I have the fluke. Its nice but I also bought an ideal so I could do motor rotation also. It comes in handy if you do a lot of motor work.


Whats the difference? If the phase is clockwise, won't the motor be clockwise?


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## Lone Crapshooter (Nov 8, 2008)

It's a big issue if you are working with transfer switches and temporary power supplies, generators and any time you are working with 2 or more power sources.

LC


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## CFL (Jan 28, 2009)

gotshokd666 said:


> Whats the difference? If the phase is clockwise, won't the motor be clockwise?


No, the motor will rotate either direction depending on how it is wound. You can check the motor rotation in relation to the motor leads before you apply power to it. This way you can make final connections early without having to possibly change them later, or probably more important, you can check the rotation on a motor before coupling it to a load or damaging something on some machines.


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## Voltage Hazard (Aug 10, 2009)

wildleg said:


> It's a little piece of junk, but inexpensive and works like a champ.


These lines don't seem to go together for me. It's a piece of junk that works like a champ? If it works like a champ, how junky can it be????


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## gotshokd666 (Oct 17, 2012)

CFL said:


> No, the motor will rotate either direction depending on how it is wound. You can check the motor rotation in relation to the motor leads before you apply power to it. This way you can make final connections early without having to possibly change them later, or probably more important, you can check the rotation on a motor before coupling it to a load or damaging something on some machines.


Ok, but on all 3 phase systems the rotation is supposed to be clockwise?


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## erics37 (May 7, 2009)

wildleg said:


> It acts like a little toy car motor, for all I know that's what's in it. So just makes me think junk, as opposed to "cadillac".
> 
> I know I've check rotation with no current flow, but now you bring it up, I'm confused as to how it works.


That means it's a good tool :laughing:



gotshokd666 said:


> Ok, but on all 3 phase systems the rotation is supposed to be clockwise?


It's arbitrary. Flip two leads on your rotation meter and VOILA! Now it's counter-clockwise


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## gotshokd666 (Oct 17, 2012)

erics37 said:


> It's arbitrary. Flip two leads on your rotation meter and VOILA! Now it's counter-clockwise


I've always checked motors based on a marking on it, if it spun in the opposite direction I switch two leads. What I am trying to clarify is how do you check rotation with a meter in this scenario? If A B C of the meter are on A B C of the motor (input) and it's clockwise then the rotation is correct?

Sorry, I'm just not real familiar with motors, trying to pick up as much as I can...


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## Bbsound (Dec 16, 2011)

gotshokd666 said:


> I've always checked motors based on a marking on it, if it spun in the opposite direction I switch two leads. What I am trying to clarify is how do you check rotation with a meter in this scenario? If A B C of the meter are on A B C of the motor (input) and it's clockwise then the rotation is correct?
> 
> Sorry, I'm just not real familiar with motors, trying to pick up as much as I can...


Because when you split bolt together a peckerhead on a 400 hp motor, you dont want to have to change it.


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## erics37 (May 7, 2009)

gotshokd666 said:


> I've always checked motors based on a marking on it, if it spun in the opposite direction I switch two leads. What I am trying to clarify is how do you check rotation with a meter in this scenario? If A B C of the meter are on A B C of the motor (input) and it's clockwise then the rotation is correct?
> 
> Sorry, I'm just not real familiar with motors, trying to pick up as much as I can...


You're not always lucky enough to get an arrow. Even with one, you don't know how the motor is wound. IDing clockwise rotation with a phase rotation sequence meter might not cause clockwise rotation on the motor. A motor rotation meter is a different tool, and you would use that to correlate proper phase sequence before you hook the motor up.

If I'm doing something like a service change, I would do a phase sequence test before I shut it down, and then write down my results somewhere. Then i would proceed to rip stuff out and rebuild the service. Then when I finished, I would do another rotation test and make sure it matched up. That way regardless of the work I did, I would know that any motors downstream would spin correctly after I switch the service back on.


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## gotshokd666 (Oct 17, 2012)

erics37 said:


> You're not always lucky enough to get an arrow. Even with one, you don't know how the motor is wound. IDing clockwise rotation with a phase rotation sequence meter might not cause clockwise rotation on the motor. A motor rotation meter is a different tool, and you would use that to correlate proper phase sequence before you hook the motor up.
> 
> If I'm doing something like a service change, I would do a phase sequence test before I shut it down, and then write down my results somewhere. Then i would proceed to rip stuff out and rebuild the service. Then when I finished, I would do another rotation test and make sure it matched up. That way regardless of the work I did, I would know that any motors downstream would spin correctly after I switch the service back on.


Ok I got it now, I didn't realize it's two seperate things. So a motor rotation meter checks the rotation of the motor itself, not the power that your bringing to it? Also, the proper rotation is clockwise?


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## erics37 (May 7, 2009)

gotshokd666 said:


> Ok I got it now, I didn't realize it's two seperate things. So a motor rotation meter checks the rotation of the motor itself, not the power that your bringing to it? Also, the proper rotation is clockwise?


The proper rotation is whatever makes the coupled load spin the right way.

I just programmed a small VFD today that the facility electrician wired up. It was just for a small hoist so the motor is normally called to go both directions. It wasn't a critical machine or anything, simply a motor attached to a gear box that makes the hoist go up and down.

I programmed it, fired it up, pushed the "Up" button and it went down :laughing: The down button made it go up. Swapped rotation and all was well. I never put a rotation meter on this one because it was just as easy to simply run the machine. But you can't always do that. The real key is that you want your phase rotation to match your motor rotation for a given direction; whether that is CW or CCW is arbitrary.


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## tates1882 (Sep 3, 2010)

I use an ideal that checks both phase rotation and motor rotation. That way it's right the first time every time.


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## jeepman (Jan 2, 2013)

I get the fluke 9040 so we will see how well it works. This motor will be 10,000 ft in the ground. It is for a ESP pump on a oil well 200kva 480 stepped up to 3811 with a y connection on the xformer. I do got pics I need to put up


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## gotshokd666 (Oct 17, 2012)

erics37 said:


> The proper rotation is whatever makes the coupled load spin the right way.
> 
> I just programmed a small VFD today that the facility electrician wired up. It was just for a small hoist so the motor is normally called to go both directions. It wasn't a critical machine or anything, simply a motor attached to a gear box that makes the hoist go up and down.
> 
> I programmed it, fired it up, pushed the "Up" button and it went down :laughing: The down button made it go up. Swapped rotation and all was well. I never put a rotation meter on this one because it was just as easy to simply run the machine. But you can't always do that. The real key is that you want your phase rotation to match your motor rotation for a given direction; whether that is CW or CCW is arbitrary.


Ok, I guess I didn't really understand how it works before. Now i REALLY get it...Thanks


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## Frank Mc (Nov 7, 2010)

erics37 said:


> You're not always lucky enough to get an arrow. Even with one, you don't know how the motor is wound. IDing clockwise rotation with a phase rotation sequence meter might not cause clockwise rotation on the motor. A motor rotation meter is a different tool, and you would use that to correlate proper phase sequence before you hook the motor up.
> 
> If I'm doing something like a service change, I would do a phase sequence test before I shut it down, and then write down my results somewhere. Then i would proceed to rip stuff out and rebuild the service. Then when I finished, I would do another rotation test and make sure it matched up. That way regardless of the work I did, I would know that any motors downstream would spin correctly after I switch the service back on.


Hi Eric

My understanding of motor rotation and phase sequence are somewhat different.... Phase sequence is important where you have say a switchboard which can be fed from 2 different c/bs fed from the same source..One can be taken out for service and the other one takes over..these can be switched on at the same time so its important that say red phase on one switch is also the red phase on the other switch ect...Phase rotation doesnt gaurentee this happens...hope that makes some sense...
Frank


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## KDC (Oct 19, 2012)

In the case of joining 2 sources that can be on at the same time, sequence is important, but all a rotational meter is going to tell you is if it's 123/ABC or 321/CBA. 

You'll still want to use a volt meter to verify the phase relationship of the 2 lines, if it's somewhere you should be sticking your hands, or some variation of phasing sticks if you're dealing with voltages in the KV range.


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## Big John (May 23, 2010)

Frank Mc said:


> Hi Eric
> 
> My understanding of motor rotation and phase sequence are somewhat different....


 Frank, I follow what you're saying: That two sources can have the same phase order, but still be out of synch with each other.

I don't know of an official definition, but a lot of protective relays refer to "phase sequence" as the CW or CCW order of the phases. The time gap between identical sets of sequences is called "phase angle."


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## CFL (Jan 28, 2009)

gotshokd666 said:


> Ok I got it now, I didn't realize it's two seperate things. So a motor rotation meter checks the rotation of the motor itself, not the power that your bringing to it? Also, the proper rotation is clockwise?


Just please don't ever mix the two up! You cannot use a motor rotation meter to check phase sequence on energized conductors. It is not built for that and it's dangerous.:thumbsup:


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## TP71 (Nov 10, 2012)

I have the Amprobe PRM-4 phase & motor rotation tester and it works great.


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