Phase rotation

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Little Bill said:
Yes, swapping any two conductors will reverse the rotation.
I don't always have a witness when checking rotation but I don't think it is overkill.
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Any two hots/phase conductors obviously right?
follybeacher said:
Am I correct in saying you can switch any two phases to reverse the rotation?
Also, do you guys qualify bumping the motor in the presence of a mechanical contractor and potentially having him sign off or is that a bit overkill?
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Bumping motor entails what? Startup?

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mstrlucky74 said:
Any two hots/phase conductors obviously right? Bumping motor entails what? Startup?

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This thread has vereed off the road a bit. All you need to do is to ensure that the existing supply and the new supply have the same phasing. That's it.
 
mstrlucky74 said:
Any two hots/phase conductors obviously right? Bumping motor entails what? Startup?

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Bumping motor to most is brief energizing of the motor, at least long enough to physically observe rotation. Many loads can handle wrong direction at least for short time, if you have a load that can not handle reverse rotation at all, you either need to verify incoming phasing before connecting to the motor, or uncouple load from motor when actually "bumping" it.
 
I was working at a large facility where one of the projects was to switch over from ten years of generator power to local utility which was finally considered reliable enough to use. After everything was hooked up and ready for the transfer, we raised halfway a large rollup door that was powered by a 3-phase motor. After the transfer, everyone in the room could see the door direction based on which button we pushed. Easy. And a load already designed to go both ways.
 
Meters/ Testers

Meters/ Testers

MTW said:
This is the model I prefer, rugged and no batteries to go bad in the housing.
Instructions PDF on the page.
http://www.tesco-advent.com/knopp-phase-sequence-indicator.html

In are experience we have found that this type of meter to be the most reliable in all load applications since it uses an actual 3 phase motor in it's design. It cannot be fooled by various line voltage conditions. On the other hand, we have found that the solid state types others have mentioned here can, in some cases, indicate incorrectly when used on high energy circuits feeding large UPS systems where high THD is present.


View attachment 21288

Along with the favorite solenoid tester. Compact and rugged.
http://www.tesco-advent.com/knopp-voltage-tester.html

These testers are fine and are great in eliminating ghost voltages but we do not recommend using them in heavy industrial environments (main bus on double-ended substations) where high energy is present. I have the older version which is not Cat III rated. We still would not use the newer Cat III rated versions on high energy circuits due to HV transients. see below

https://content.fluke.com/promotion...dmm/fluke_dmm-chfr/files/safetyguidelines.pdf

View attachment 21289[/QUOTE

This post is in response to MTW in post #13
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mstrlucky74 said:
Any two hots/phase conductors obviously right? Bumping motor entails what? Startup?

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Here is a easy way to look at it, draw it out for yourself. Any change will result in a direction change.
It looks like i cannot upload pictures...draw a triangle and put a 1,2,3 at each point. Then change any 2 numebers- note how it changes from clockwis to counter clockwise. Maybe another member can draw a pic of this...hope it helps.
 
rambojoe said:
Here is a easy way to look at it, draw it out for yourself. Any change will result in a direction change.
It looks like i cannot upload pictures...draw a triangle and put a 1,2,3 at each point. Then change any 2 numebers- note how it changes from clockwis to counter clockwise. Maybe another member can draw a pic of this...hope it helps.
Click to expand...

What problem are you having loading pics?
 
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