motor rotation 3

[mec1]

can i determine the motor direction will be before starting it up even iff there is no wire nos on the wires coming out of the motor

 

[busbar]

Mechanical rotation and phase sequence are not standardized in ANSI regions.

 

[pablo02]

You didn't mention the type or phases of the motor -- are we to assume a 3 phase AC motor?

 

[SteveKW]

A place to start...

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=motor+phase+rotation+&btnG=Google+Search

 

[mec1]

it is a three phase ac induction motor i see there is meters on the market to ascertain motor direction

 

[Kiribanda]

Hello mec1,

1)If your motor is manufactured as per IEC 60034, then if you provide a power supply having positive phase sequence of R,Y,B to the motor with U,V,W terminals (as per the same alphabatical sequecnce ) then the motor should run CCW (anticlockwise) seen from the non-drive end (IEC 60034-8).

2)If your motor is NEMA rated one then there is no any specified standard direction of rotation related to the terminal markings for polyphase induction motors.
But for all NEMA rated single phase motors,universal motors and all syn. motors the direction of rotation should be CCW seen from the non-driving end when positive sequence is given to 1,2,3.

Regards!

Kiribanda :->

 

[OperaHouse]

There are good phase rotation meters with amplification that can tell you that.

http://www.rke.com

is one company that has one. A motor will generate a few milivolts of AC when you turn it by hand so you can determine sequence.

1. What you do is hook up the 3 phase power to the meter. 2. Press the test button. If it lightd up, mark the leads. If not, reverse two leads.
3. Now connect the test leads to the unpowered motor. Rotate the motor in the direction you desire and press the test button. If it lights up, mark these leads. Otherwise switch a pair.
4. If you pair up the power and motor leads, it will turn in the desired direction when power is applied.

 

[jbartos]

Suggestion: Some motors have an arrow showing the motor direction of rotation that is supposed to be implemented and should not be violated.
If the above does not work, one may search for the motor direction of rotation on the load side, e.g. an attached pump may have an arrow showing the proper motor direction.

 

[GGOSS]

Hello Mec1,

Assuming its a three-phase AC motor we're talking about and you dont have available to you the required instrumentation to determine rotation, the suggestion made by jbartos is probably the most suitable for you. However I would add that it would be wise for you to un-couple the motor from the driven machine, particularly if the driven machine is rotation sensitive eg pumps, chiller compressor etc etc. Running these types of machine in reverse rotation may result in irrepairable damage!

Regards,
GGOSS

 

[jbartos]

Suggestion: If there are no indications of the direction of rotation, e.g. arrows, nameplate, etc., one may also contact the manufacturer tech support. The motor may be uncoupled from the load to investigate it; however, the actual start of the motor-load set should be after all pertinent informations are in-house and implemented.

 

[king144]

The only only fool proof way to test the motor direction is to run it uncoupled once it has been installed and powered up.

The phase meter methods will work but are not fool proof - power leads can get crossed, contactors modified, distrubtion switches rewired and so on during new construction...

Safety is a consideration if your motor or it's load is designed for unidirectional service. Some pumps can be ruined in one start-up if run backwards...


Richard Anderson
GP Mill Camas, WA

 

[electricpete]

I agree with Kind, particularly for large motors.

In that case our standard practice is to run the motor solo prior to coupling it. During that run you can not only check the direction of rotation, but also check the vibration and no-load current. That provides a little extra info which is useful for two reasons:
1 - may help to identify motor problems early (before effort is expended to align and couple)
2 - if there should be a problem which occurs after coupling and loaded starting, the troubleshooting is simpler because some apsects of motor have been ruled out.

 

[buzzp]

Phase sequence meters will only tell you phase rotation, positive (ABC) or negative (CBA). I suppose if you move them around enough you can determine which is A if need be. Uncoupled start is recommended if your there are any doubts.

 

[jbartos]

Suggestion to mec1 (Mechanical) Jul 26, 2003 marked ///\\it is a three phase ac induction motor i see there is meters on the market to ascertain motor direction
///Actually, some motor direction of rotation testers are suitable for the single phase, two-phase and three phase motors.
Visit

http://www.multimex.com.mx/560060.pdf

for "Features and Benefits" paragraph\\\