3ph motor rotation
3ph motor rotation
(OP)
I've always used the thumb rule saying that if a 3ph motor is connected in the basic sequence, ie R-S-T/L1-L2-L3, on the motor terminals starting from the left, the motor will always rotate clockwise when look in to the shaft end.
I've bumbed in to some motors which apparently doesnt "follow" this rule. Im told that the grid supply in to the yard is in the correct sequence, and I do not have a meter to verify if this is correct.
Anyone able to confirm the thumb rule, so I can contend that the grid is wrong?
Thanks in advance.
I've bumbed in to some motors which apparently doesnt "follow" this rule. Im told that the grid supply in to the yard is in the correct sequence, and I do not have a meter to verify if this is correct.
Anyone able to confirm the thumb rule, so I can contend that the grid is wrong?
Thanks in advance.





RE: 3ph motor rotation
You should check both motor and power phase sequence or bump test the motor.
There are several instruments on the market which will tell you power and motor phase sequence.
RE: 3ph motor rotation
If safety or correct operation matters, it is a serious mistake to make assumptions.
Testers are readily available to determine phase sequence.
RE: 3ph motor rotation
The package, with the motor on it, is to be shipped away to another loaction, so the issue is just to avoid swapping of cores later on
Verifying the rotation locally and that jazz is all fine
RE: 3ph motor rotation
Don't know the motor location, but in ANSI/NEMA regions, there is no "r∙o∙t" specifying direction of induction-motor rotation. Thread237-40638
RE: 3ph motor rotation
IEC motors do. It is imposed by the standards that govern motors.
Unfortunatley, the only place NEMA MG1 makes this is a requirement is in section 31 for Definite Purpose Inverter-Fed motors. The fact that US motor manufactures are not otherwise bound to a convention for AC Induction motors, is what prevents Inverter Motor Manufacturers from stating on the nameplate of their so called Inverter motors ... NEMA MG1-31 compliant. They can meet all of the other requirements for insulation, rise time, etc... but they don't conform to the "Direction of Rotation.... section 31.30.6
RE: 3ph motor rotation
RE: 3ph motor rotation
RE: 3ph motor rotation
If you see an IEC motor running anti-clockwise (viewed drive end) it is either because two of the incoming leads have been switched, or that the phase sequence of the leads isn't U-V-W due to either a wiring fault upstream or because it is operating on a reversible inverter drive.
RE: 3ph motor rotation
Here are some samples from the web:
http://www.sunonusa.com/spec/KDE0501AFB2-8(MS-OC).pdf
http://www.ketterer.de/e_images/Final_4640_engl.pdf
http://www.titancranes.com/crane_data_sheet(us).PDF
http://www.jlab.org/ccc/mail_archives/CLAS/clas_slow_control/msg00052.html
etc.
RE: 3ph motor rotation
RE: 3ph motor rotation