Induction Motor Run Test at No Load

Why not test run the motor in the workshop before fitting to the bed plate? If there's a bearing problem it will show within an hours run. You're not going to get much more information with no load testing.

Normally 12hr continous no load trail can be taken, for initial commissioning trail run test of IM's.You have to ensure proper alignment before inoder to avoid bearing problems, vibration problem.

Dear Mr.itsphani99,

Pl. explain basis for 12 Hrs. testing.

I do not know in which country you are, but one Motor Manufacturer, whose Factory I visited, for small motors up to 100 H.P., are tested for 2 hours in each direction, and for bigger Motors upto 500 H.P, 3 hours and above 500 H.P., 6 Hours.

DHAYANANDHAN.S

Incredible ambiguity begets unenlightened responses.

You must assure complete alignment and balance before running the pump.

And, don't run it dry.

That will likely be the outcome in any case.

First get information required from manufacturers- current,noise level,speed,bearing temperature etc at no-load and full load and compare with your test results.

Dear Friend,

What is the issue.? Normally 10 to 15 Min. empty motor trial will be taken, with out coupling to the load, be it pump or any other equipment.

Normally pump will be alligned, bed bots tightened and then Elec. connection is made and empty trial taken, observe/measure the vibration level, note the No-Load Current if all is OK, then couple to the pump.

No-Load Current will be 30 to 40% of Full Load current, as the P.F is low at No-Load, since the Line Current follows the CIRCLE DIAGRAM and NOT the linear line.

DHAYANANDHAN.S

dear....

you are testing 120 HP lt motor with out load. ok. befor testing tight all bedding bolts,and nuts, and also at pannel end. motor terminel plate, earthing, Make shure that cepacitor will be in ON. 1st test intial current, and running current with clamp meter. it should be up to 35 % of full load current, i.e 52 A for 15 min in all directions.if it is constant that is good.

Lately they have tried to develop a special motor to run efficiently in one direction only thereby saving materials.

We test the motor on no load for a duration till the bearing temperature and vibration readings stabilize and do not show increasing trend.