100 Hp 480 volt 3 phase pump motor
100 Hp 480 volt 3 phase pump motor
(OP)
Good in electronics and telecom, new to BIG 3 phase motors!!
I have an ag well pump.... 100 Horsepower 480 3 phase "part wind" (6 wire) motor with a "starter" (just 2 big contactors really) one has a phnumatic time delay adjustable from 0 to 40 seconds(as found set to 0.1 seconds)unit is 12 years old. Both contactors have one phase melted open and 2 phases welded shut!!! Haven't meggered the motor yet.... My question: should the 1st contactor close then , 3 or 4 seconds later the 2nd contactor close, (the way the pump on my farm works)or should both contactors close at the same time??? And if the timer was not set correctly, would that have possibly caused the contactors to burn up???? (I found an old contactor in simular burnt up condition laying in the bottom of the control panel!!!)
I have an ag well pump.... 100 Horsepower 480 3 phase "part wind" (6 wire) motor with a "starter" (just 2 big contactors really) one has a phnumatic time delay adjustable from 0 to 40 seconds(as found set to 0.1 seconds)unit is 12 years old. Both contactors have one phase melted open and 2 phases welded shut!!! Haven't meggered the motor yet.... My question: should the 1st contactor close then , 3 or 4 seconds later the 2nd contactor close, (the way the pump on my farm works)or should both contactors close at the same time??? And if the timer was not set correctly, would that have possibly caused the contactors to burn up???? (I found an old contactor in simular burnt up condition laying in the bottom of the control panel!!!)





RE: 100 Hp 480 volt 3 phase pump motor
RE: 100 Hp 480 volt 3 phase pump motor
RE: 100 Hp 480 volt 3 phase pump motor
A common contact fryer is a condition where as the contactor closes you get a large inrush which drops the voltage enough to cause the contactor to open which drops the current enough to to let the voltage rise to a point where the contactor can close again.. Of course this happens rapidly until the contactor is toasted or the motor opens or a fuse blows or a breaker opens.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: 100 Hp 480 volt 3 phase pump motor
Check the motor first. If it is found OK, I suspect the 0.1s timer setting did it, that is contactors were subjected to inrush current in excess of its rating.
From past experience, single phasing seldom affects large motor such as this, specially if its reasonably loaded. But on the other hand pumps have low running torque so never know.
There could be many other suspects:
Did anyone worked on the starter recently? Because a miswiring (bringing two phase together) can do this type of damage.
Was motor running just fine, before the mishap or there was a history of replacing the contacts or the contactors?
Was the 0.1s setting known to exist before?
RE: 100 Hp 480 volt 3 phase pump motor
My bag is really Telecom, 2-way radio, Microwave, Fiber, and SCADA.
I thank you all for your replies!!!!
RE: 100 Hp 480 volt 3 phase pump motor
Good luck!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: 100 Hp 480 volt 3 phase pump motor
RE: 100 Hp 480 volt 3 phase pump motor
http:/www.jraef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: 100 Hp 480 volt 3 phase pump motor
respectfully
RE: 100 Hp 480 volt 3 phase pump motor
RE: 100 Hp 480 volt 3 phase pump motor
JR