Waross,
Thank you for your input.
We are using secondary voltage as 115V for our applications. SO there is a jumper between X2 and X4; X1 and X3. Our circuit is connected to terminals X1 and X4. So I think the connections are good. See the attached for reference.
There is another aspect we...
We have the following CPT installed for our motor circuit controls;
Primary 4160 VAC
Secondary 115/230 VAC
3KVA, 60HZ, K-Factor 1
3A fuse on primary, 20A fuse on Secondary
We installed these CPTs a few months back in 4 of our motor feeder units.
We had trip incidents on all 4 motors and...
The timing on the picture was wrong, as it was set improperly. This event happened on new gear, installed recently.
We don't want to trip the breaker on UV, so currently thinking to change to Alarm only. We thought UV can happen when there is a trip in the upstream line and excessive load on...
One of our Micrologic 5.0 P main breaker has been tripped due to Isd = 7500A, due to a blip in the 25KV high voltage side.
We are thinking about adjusting the Under-voltage trip settings but there isn't any history of UV trip on the trip unit.
We are trying to identify the root cause and come...
Attached for the Motor name plate details. https://files.engineering.com/getfile.aspx?folder=c7479f0e-ce5a-4138-840b-4843ab105d35&file=Pump_A_motor_Name_plate.jpg
I want to know more details on this GE Fuse, It is hard to find the info on the Web.
Please see the attached. Does this fuse come under Nontime Delay or Dual element(Time-Delay) Fuse?
According to NEC code, what should be the Max fuse size that can be used for 460V, 220A, H Class, 60HZ...
These cables are routed through Cable Tray. I will check for the grounding, I am confident that we don't have a grounding on the cables.
I don't have an exact 1200A Fuse photo, but I have 800A which is similar. See attached for reference...
@Rahunath
There is a Very OLD gear, there is no overcurrent protection with trip settings and delay time on the feeder breakers. In that case, there is no Incoming Main Breaker to isolate the Switchgear from Transformer. You can see it on SLD.
@ Kiribanda
Thank you for your input. Yes, the Transformer is solidly grounded. The fuses for the feeder are 1200A. We observed that one of the feeder breaker fuses were blown.
As far as the cable grounding between feeders and the Motor, these are 3/C 500 MCM cables. There is no grounding...
The Breakers doesn't have any LT/Inst trip units on it, been though these breakers are feeding cooling tower pump motors.
Testing was done on the Breakers 2 years back and they have a testing sticker on it. The heaters are not working on the switchgear. The incident started at one cubicle and...
One of Old GE Powermaster low voltage switchgear experienced a major arc flash incident a few days back. We are looking for a potential root cause for this incident.
Please see the single line for reference, there is no overcurrent relay protection on the gear. We are looking into several...
We have 4160V, 500HP Synchronous motor tripped yesterday. There are no flags on the GE multiline relay and the PF trip is disabled on the relay. We did the Megger, Temp measurement, PI on the motor, everything is normal. This Motor is 25 years old, and the excitation is not AVR controlled, it...
Would appreciate it if you can provide your thoughts on the Preventive Maintenance Strategy for Motors.
I am particularly looking for 3 phase Motors under 100HP. What should be the replacement period for motors under 100HP, based on the criticality level of A, B, C? Which standards are a good...
waross, RRaghunath
The trip is not due to overvoltage, it is due to overload only. Sorry for the confusion, I got myself clarified recently.
Currently, the transformers are at Tap-03, 12.5KV/4160V. According to motor data, it is rated for 2300V/4000V.
Currently, the voltage on GE multiline...
It is a 3 phase, 2300/4000V, Induction motor, 1250HP, FLA 279A. Please see the attached for motor nameplate details.
Our system's nominal voltage is 4160V. It has been in service for more than 15 years. The trip occurred due to overcurrent, not overvoltage, due to blockage in some valve, it...
One of our essential old motor is running on 4160V, but the Electromechanical relay is set at 4000V. The current overvoltage trip for the motor is at 1.1 X rated (i.e 4400V) and the alarm is 1.09 X rated (i.e 4360V). Recently the motor tripped due to Overvoltage. We are looking for options to...
