Motor contactor drops out . ( PQSI Model 1002-120V-CE ) Possible fix ?

[Davebones]

Have one of our test stands the 150 hp main contactor occasionally will drop out when we start the sump pump on the stand . This is a small 1/4 pump 120 volt . After going thru the stand the only thing I can see is a voltage drop when this pump starts might be causing this . I found this ( PQSI Model 1002-120V-CE ) relay online which they claim will prevent this from dropping out until the voltage falls below 30 vac . Wondered if anyone has used this product before ???

 

[retirede]

Motor contactor drops out . ( PQSI Model 1002-120V-CE ) Possible fix ?

Without seeing a schematic, it's really hard to say what your problem might be. But I will say that if you have a test stand that can run a 150 HP motor, I Seriously doubt that the starting of a 1/4 HP pump will cause enough voltage drop to drop out that contactor. I would look for loose connections or some interlocking device that is out of adjustment or malfunctioning.

 

[Davebones]

The sump pump is fed of the motor control circuit . We use a separate 120 volt control circuit so we can troubleshoot without having 480 volt energized inside the controller cabinet . I have gone thru all the wiring nothing loose . Even did a temp hook up with another style size 5 starter and still had the issue . Not a long distance on the control wiring either maybe 40 ft max between he pump skid , controller cabinet , and test stand . Test stand lights dim a little when we start the sump pump .

 

[Jraef]

1/4HP 115V motor is 5.8FLA, so starting current could easily be 40-70A. That could easily overwhelm whatever you are using as your 120V control power source. I would not design it this way at all. But now that you have, either totally separate that 1/4HP motor source, or make sure your 120V control power can handle a 70A surge. For example if you are using a 16ga extension cord to get your temporary control panel, get a bigger cord, 12 ga minimum I'd say, 10ga would be better to just totally illuminate the possibility of voltage drop on starting that motor.

 

[Davebones]

Installed the PQSI 1002-120V-CE Relay and it solved this issue . We have at least 10 test stands set up this way and this is the only one that had this issue . Not all the stands have the same size sump pump as it depends upon the fluid tank size . We designed the stand with separate 120 volt control power as we can isolate the 480 volt and troubleshoot the controls without having to worry about arc flash. We also go thru a GFI for added safety as we have oil and water around these stands . Rarely have we had nuisance trips of the GFI .

 

[Fnewman]

Also bear in mind that if you have one or more of the little cube type relays that plug into an 8 or 10 pin socket in the control circuit, the drop-out point is pretty high relatively to industrial relays.

 

[kwired]

Also bear in mind that if you have one or more of the little cube type relays that plug into an 8 or 10 pin socket in the control circuit, the drop-out point is pretty high relatively to industrial relays.

But they also don't have as massive of an armature to hold in like the (presume OP has a..)size 5 contactor has.