Three phase motors are NEVER marked for rotation. They are designed to go either direction. You choose the direction you need. Pumps/fans/ect... have an arrow or some marking to allow it to operated properly.
Some applications I have worked on, call for the motor to use both directions on the same piece of equipment.
What good would it do to mark the motor? The motor mfgr. has no idea how you are going to hook it up or what the incoming line sequence is at your facility. ABC is relative. For instance, PG&E here in California is A-C-B with relation to other facilities in the US, but that means nothing to everyone local here. It just is what it is.
CBS: Connect it, Bump it, Swap leads if needed
Re: Electric motor rotation
#170482 11/04/0710:25 AM11/04/0710:25 AM
jraef, Correct my friend. When I supervised a motor shop some years ago, some customers would call and ask if we could mark the leads, so the motor would turn in the direction they wanted without "bumping". Of course we could not garranty rotation on three phase. There are some phase detectors on the market that claim they can do this. But how can you know the complete facility is phased exact at every panel, disco or motor starter. I have even seen some companies try to do this. I have never found any of them to be successful.
Now, DC motors can be wired for a particular direction, but it must be a "shunt wound, compound wound or series wound motor.
On the other hand, some motors work too well backwards. Our bus garages use 5 HP Red Jacket STPs in our underground storage tanks. (USTs) I always tell our electricians to check them both ways after replacement. I ask them to check static pressure and to squeeze off 10 seconds and check the flow rate. More than once, they've told me they didn't bother because it looked fine. I jumped on them about why I would waste my time asking them if I didn't feel it to be important. At least half the times, they've called back telling me that they got higher pressure and flow after switching the leads. Joe