230V Connected Electric Motor Running Opposite Direction When Connected for 460V 2

[ILikeLearning11]

Hello - forgive me as this is not my expertise -- but I have a customer claiming that when they wire up an electric motor (230/460V dual rated motor) --- that when it's wired for 230V, it runs in one direction. And when they hook that same motor up for 460V, it runs the opposite direction.

Let's assume they wired it up the same way with each phase for both --- is this a possible outcome? I have asked a couple of electric engineers who have said it's not but the customer is adamant about it. He is one to never admit he's wrong so I'm trying to have multiple sources to prove it's not possible. I think they are potentially just mixing up phases when changing the voltage connections -- which could cause the opposite rotation.

However, if it is possible, then please let me know. Thanks in advance!

 

[edison123]

Wait, they have both 230 and 460 V, 3 phase supplies available in the same facility?

The label below is self-explanatory.

Muthu

http://www.edison.co.in

 

[3DDave]

Here's the likely problem. Someone wired the facility (or somewhere in the facility) backwards between the two. No one has noticed because whenever they hook up a motor, if it runs backwards, they just swap the leads and tell no one.

Except on this motor.

They are probably following the color code correctly at the motor, but it needs to be traced farther back.

Is it possible the motor maker screwed this up? I guess. But it is far more likely for the electricians wiring a factory to make a mistake than for a motor winder to do so.

The answer is to have an electrician confirm the phase relationship between the two supplies. The trouble may be in getting a tester with the upper voltage range. Maybe this:

https://calright.com/product/reed-r5044-non-contact-phase-rotation-tester/

though the electricals here likely have a better recommendation.

 

[cranky108]

Being it is a dual voltage motor, it maybe in the connections that reverse the direction of the torque.
This is just theory, as I have not seen it myself.
Just switch two phases.

 

[waross]

Dave has it.

Here's the likely problem. Someone wired the facility (or somewhere in the facility) backwards between the two. No one has noticed because whenever they hook up a motor, if it runs backwards, they just swap the leads and tell no one.

Been there done that.
Phase reversal between 240 Volt system and 480 Volt system.
[AA](Anecdote alert)
I was working on the startup of a large pulp and paper complex.
The phase rotation was kept uniform throughout the plant.
The electricians were able to predict the direction of rotation when they connected each motor.
As we worked through the plant, almost every motor rotated in the correct direction.
Anyone who has done a similar startup knows that motor rotation is often random at about 50:50.
We had one or two motors running the wrong way, but there had been some confusion as to which way the motor should run when the motor was connected.
We had dozens of MCCs to work through.
Then, in one part of the plant, all of the motors ran backwards.
We checked the connections and they seemed correct.
Then we looked at the MCC.
We had many back-to-back MCCs, that is, completely separate MCCs mounted back to back.
In the entire complex there was one two sided MCC.
That is buckets on both sides but sharing vertical bus bars.
So, on the front of the MCC, reading left to right, the phases were A, B, c.
On the back of the MCC, connected to the same bus bars, the phases were C, B, A.
Good catch Dave.
By the way, if they reconnect an existing 460 Volt motor for 230 Volts it will run backwards on the same system.
lps, Dave

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[waross]

The answer is to have an electrician confirm the phase relationship between the two supplies. The trouble may be in getting a tester with the upper voltage range.

Back in the day we used a small motor for a tester.
Wait.
They just did that.
Suspicion confirmed.
The 480 Volt phases are reversed relative to the 240 Volt phases.
The End.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[che12345]

"...Back in the day we used a small motor for a tester..".
1. Nowadays we use held held tester. Gone are the days of using a small 3-phase motor. These are either:
a) New electronic Phase rotation indicator, battery or without battery operated. Line-to-Line voltage up 700V ac 50/60 Hz.
b) Old rotating disc Phase rotation indicator, without battery operation. Line-to-Line <600 V ac 50/60 Hz. Attention: limit connection to the mains to < 5min (see manufacture operation instruction).
2. Attention:
a) In the IEC world, mains sequence A,B,C connecting to motor winding U,V,W for Clock-wise rotation.
b) In the US NEMA, mains sequence A,B,C connecting to motor winding T1,T2,T3 is NOT defined CW or CCW rotation, unless the terminals are marked U,V,W., for CW rotation.

Che Kuan Yau (Singapore)

 

[waross]

NEMA World.
Clockwise rotation viewed from the non-drive end is standard from most manufacturers.
We did use a rotation meter to check motor rotation direction.
As I said, the phases were identified and carried through with either numbered or coloured core cables.
We knew the phase rotation,so we didn't have to check that until we encountered the small reversed phaseMCC.
That was about 50 years ago and most small shops (and a lot of larger shops) did not have rotation meters.
If the rotation was critical, a small motor was used to check phase rotation.
Even back then, CW-NDE was almost universal.

Old rotating disc Phase rotation indicator,

Yes we installed many of those on standby generator installations. But they were expensive and you didn't find spare rotation protection relays lying around while small motors were easy to find.
The motor test is still valid and as I pointed out, the OP has performed a phase rotation check with his subject motor.
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[che12345]

"...NEMA World. Clockwise rotation viewed from the non-drive end is standard from most manufacturers".
I wish to point out the following differences between the IEC and NEMA, NEC.
1. Colour Code for phase sequence A,B,C .
a) IEC: L1 (Brown), L2 (Black) ,L3 (Grey) , N (Blue), E (Green-yellow).
b) NEC: Ungrounded conductors shall be distinguished by colour other than White, neural Gray, or Green.
2. Motor direction of rotation
a) IEC: Clockwise rotation when view from the Drive shaft end; with phase sequence A,B,C, line conductor L1, L2, L3 to motor terminal U1, V1, W1.
b) NEMA: The standard direction of rotation for polyphase induction motors shall be CCW when facing the end opposite the drive end. No direction of rotation is defined when terminal marking T1, T2, T3 are used.
3. Attention: CW view at the Drive end would be CCW when facing the end opposite the Drive end.
Che Kuan Yau (Singapore)

 

[LionelHutz]

No, I don't believe the customer. If you look at the connections on a 6, 9 or 12-lead motor the same end of the coils always connects to the same phase which would cause the same rotation direction.

 

[cranky108]

Doesn't anyone use a phase checker? I don't think they are very expensive.

 

[waross]

But cranky, the motor WAS the phase checker.
It showed conclusively that the 480 Volt phases were reversed relative to the 240 Volt phases.
Swap two leads and move on.
I once got fired over "Swap two leads".
A manager told me to have ONE lead only taped temporarily in the event that we had to change it to reverse rotation.
I asked for clarification and he repeated,\;
"Leave ONE lead taped temporarily in case we have to change it."
(By the way,we had evaluated the issue and realized that it would be quite difficult to swap leads at the motor but it would be quick and easy to swap them in the MCC bucket.
I asked again.
Same answer.
I was tired and hungover. Not my best day.
I forget my exact retort, but he went away and left me and my hangover in peace.
I found out later that he had gone into the office and demanded that I be fired.
Someone asked why, and when he explained, someone with more tact and electrical knowledge convinced him that firing me was not the best course of action.
Fired and rehired before I even knew.
Not my first motor.



--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[edison123]

A dual voltage motor can run in opposite direction only if the phase sequences 230 V and 460 V systems are not the same. And I still doubt a facility could have two low voltage systems.

Phase rotation checker, trial motor run etc. do not guarantee that all motors will rotate in the same direction as indicated by them since the motor terminal leads could have been wired u/v/w or u/w/v.

Check the motor rotation direction in decoupled condition first before you couple it to the load. It takes less than a second.


Muthu

http://www.edison.co.in

 

[davidbeach]

Multiple low voltage systems are not that uncommon. Easily happens when the facility was built with the 240V system (230V motors) and then expansion drove the need for a newer service with more capacity and the 480V service (460V motors) was added. The 240 wasn't eliminated for cost reasons. It may remain as a separate service, or it may be fed from the 480V service.

Once dealt with a semiconductor facility that had a MTM MCC arrangement. Lots of motors on both sides of the tie. After everything was connected and the plant running the facility engineer decided to check voltages across the tie for what ever reason. Discovered that one side of the tie had one phase rotation and the other side had the other rotation. The tie was useless and couldn't be made useful without more rework than anybody desired and the handle was removed with the breaker in the open position.

When one this sentence into the German to translate wanted, would one the fact exploit, that the word order and the punctuation already with the German conventions agree.

-- Douglas Hofstadter, Jan 1982

 

[waross]

I have installed many 480:120/208 Volt transformers and breaker panels in industrial plants.
Large shopping malls may have a 480 Volt service and system for larger equipment. They will also have 120/208 Volt systems for the numerical bulk of their loads.
In such cases, the equipment room is generally close to the main service panel.
Equipment installed some distance away will often be fed 308 Volts from a local 120/208 Volt panel rather than running what may be hundreds of feet of feeder from the 480 Volt panel.
Lighting and a lot of smaller motors are on the 120/208 Volt systems.
When local feeders are not cables but are conductors in conduit, many times the three black conductors are connected at random in local panels, without regard to phase matching nor rotation.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Heaviside1925]

waross I have seen the same and installed many systems like you describe. Small manufacturing, where half the building is offices requiring a lot of 120, and the other half is the manufacturing floor. Equipment is installed based on closest panel, which may be either 208 or 480.

Just a note. I am hoping OP comes back on and confirms. In rereading the original post, OP never mentions the voltage being supplied to the motor. I made the same assumptions that the rest of the commentors did about rotation being different between the two systems but now I am wondering if OP was just referring to the motor lead high/low configuration, which would be a whole different question all together.

 

[waross]

Hi Heaviside;

that when it's wired for 230V, it runs in one direction. And when they hook that same motor up for 460V, it runs the opposite direction.

Let's assume they wired it up the same way with each phase for both --- is this a possible outcome?

Reading between the lines;
when it's wired for 230V, it runs in one direction. Assume that they had a 208V or 240V source to check rotation.

when they hook that same motor up for 460V, it runs the opposite direction Assume that they had a 208V or 240V source to check rotation.

Yes I know about phase rotation meters and have been using them since about 1985.
I have also many times used a small motor to check phase rotation many times.
I we were onsite the first question that we asked may be;
"Is there a phase rotation meter available?"
If the answer was no, then the second question may be;
"Do you have three phase motor that we can use for a test?"
WAIT. THEY JUST DID THAT.
The test results?
The phase rotation of the 240 Volt system is opposite to the phase rotation of the 480 Volt system.



--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[ILikeLearning11]

Just a note. I am hoping OP comes back on and confirms. In rereading the original post, OP never mentions the voltage being supplied to the motor. I made the same assumptions that the rest of the commentors did about rotation being different between the two systems but now I am wondering if OP was just referring to the motor lead high/low configuration, which would be a whole different question all together.

Sorry for taking long to respond - but man I’ve learned a good amount already. To clarify, this is an OEM with a production line — some units go out connected for 230V (most are 460V). He is saying that on that production line - if they switch voltages, the motor runs the opposite direction. I don’t necessarily believe it is the motor but something different. Y’all have given me quite a few things to check but also I think the next time they “think” this has happened, I would want them to hold that motor until we can come observe it. I suspect it’s not the motor but another possible thing y’all have pointed out.

 

[waross]

A second test that doesn't need a tester and may be more demonstrative.
Connect a 460 Volt motor to 480 Volts and check the direction of rotation.
Without changing any connections, connect the motor to the 240 Volt source and watch it turn backwards.
Reverse the main connections on the 240 Volt system, or at least on the 240 Volt test rack.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Heaviside1925]

OP,
No need to apologize! Thank for the follow up post. A lot of folks seem not to and it helpful to me when someone pops back on to say whether or not anything I said was helpful or it tuns out I was plain wrong. Good luck in running this down.