Hi,
I'm a bit of a lurker; have not been too active here before though. I'm an Electrical Engineering Student in hopefully my last year and have been working as a Field Technician for the last ten years or so.
I work in a refinery where there is a small variety of motor protection; usually some type of GE Multilin, the very occasional Macrotek, and even the electro-mechanical type as well.
I ran into the problem with the M60 while troubleshooting another intermittent problem that seemed to be surfacing on the protective side of a 4160V Motor-Starter. The style of relay is a M60-C00-VFH-F8A-H5C-M8A-P6B and the version is 3.44.
Upon simulation of start up and transferring to a running state at FLA, the relay would trip off within two to three seconds. At inrush to 95%FLA and 105%FLA, would run pretty much forever. But at 100%FLA, would pause, and trip. I tested another at this point and had the same phenomenon happen. Upon investigating the trip calculations, it seemed that the relay has a divide by zero problem when the motor Service Factor is set at 1.0. Rather than tripping in an infinitely long time, the relay buggers out and trips quickly on a Thermal trip.
I was looking for some outside information/experience as GE Multilin only stated that they don't suggest to set the SF at 1.0. My thoughts are that it shouldn't be available if it's going to nuisance trip at FLA if the motor is derated to 1.0 or happens to be rated at 1.0. Has anyone else came across this before and dealt with GE regarding it?
Thanks
I'm a bit of a lurker; have not been too active here before though. I'm an Electrical Engineering Student in hopefully my last year and have been working as a Field Technician for the last ten years or so.
I work in a refinery where there is a small variety of motor protection; usually some type of GE Multilin, the very occasional Macrotek, and even the electro-mechanical type as well.
I ran into the problem with the M60 while troubleshooting another intermittent problem that seemed to be surfacing on the protective side of a 4160V Motor-Starter. The style of relay is a M60-C00-VFH-F8A-H5C-M8A-P6B and the version is 3.44.
Upon simulation of start up and transferring to a running state at FLA, the relay would trip off within two to three seconds. At inrush to 95%FLA and 105%FLA, would run pretty much forever. But at 100%FLA, would pause, and trip. I tested another at this point and had the same phenomenon happen. Upon investigating the trip calculations, it seemed that the relay has a divide by zero problem when the motor Service Factor is set at 1.0. Rather than tripping in an infinitely long time, the relay buggers out and trips quickly on a Thermal trip.
I was looking for some outside information/experience as GE Multilin only stated that they don't suggest to set the SF at 1.0. My thoughts are that it shouldn't be available if it's going to nuisance trip at FLA if the motor is derated to 1.0 or happens to be rated at 1.0. Has anyone else came across this before and dealt with GE regarding it?
Thanks
