Insurance company wants us to test all of our unit substation secondary breakers. They all GE AK breakers 600 and 1200A. They have all been retrofitted with AC Pro trip units within the last 10yrs.
Should we use primary or secondary injection for the tests. I don't think primary is a good...
I'm installing a new battery next week in our main substation, and wanted some advice. Load will be 12 GE magneblast breakers. Nominal voltage is 125, closing coil is 90-130 95A and the trip coilis 70-140 6A. The system I'm replacing consisted of 54 cells but looking at the PO 60 were purchased...
2 different drives are experiencing higher than normal bridge temps after a 6 month shutdown. Both are ABB DCS 500's. One is for a 40 hp motor, the other is for 2 75hp with the armatures in series. They are both way under FLA. Before the shutdown these drives both had bridge temps under 30C...
As the subject says, production resets the relays without any thought about a downstream fault. This is on 4.16 GE switchgear from the 50's. Faults are uncommon, but when there is one the relays are reset, and the breakers are closed several times before an electrician is called. We don't have...
What is the proper way to maintain and measure these types of bearings? We have an 8" and a 10" bearing supporting a 9 ton rotor turning at 180 rpm. The bearings are split with two oil rings for lubrication. Average clearance is about .045" measured in 3 places on each bearing. The journals show...
Has anyone used the 744 for configuration and testing of Rosemount pressure and temperature transmitters? I'd like to be able to source T/C and RTD and also read and configure the devices. We have a few Emerson 375's, but they leave a little to be desired.
I'm working with 2 different motors, and I'm trying to interpret some basic test results. I have 2 1250hp 4160V 40 pole sync motors, Field is 250V 66A and the field discharge resistor is 33.4 ohms. The Field is supplied by an SCR rectifier thats mounted in the substatation by the starter. The...
Just a follow up on my post from a few weeks ago. Last night we had a Joslyn Clark relay blow up and take the exciter with it. I've been looking for a suitable replacement for these, but have not had the best of luck. Seems like no one makes these kind of contactors any more. The only one i've...
I'm having a hard time grasping the tap settings on these relays. Is there a simple explanation for setting them up properly. I'm not looking at making any changes, just wanting to understand how to select the proper taps.
We have several 1250hp synchronous motors using JC dc contactors to apply the field. Field amps are usually around 66. The contactors are three pole with two NO, and one NC. The NC contact connects the field windings to a discharge resistor, and the NO's apply the field when the motor is up to...
I have the need for a 4-20 in 0-50 out signal converter. Are these still available? The existing unit is made by action instruments. I have searched the net with no luck. Was this a common control loop in the past. We are using this to control a servo valve on a hydraulic pump.
What are the recommended materials for re potting GE Magneblast breaker bottles. Ours are showing signs of cracking and seperation between the bar and potting compound. We were smelling ozone, and called in a specialist. He chiseled out the old potting compound re wrapped the bars with silicone...
Does NU324 DE and 6222 ODE sound like a proper setup for a vertical mount motor. Motor has large sheave hanging on it, 8 C belts if I remember correctlyl. 1750 rpm 300hp. We had the motor refurbished last year, and after putting it into service there is some strange noises coming out of the DE...
We recently had our GE Magne-blast 1200A breakers serviced during our annual outage. It's been about 3-4 weeks, and we're starting to notice the smell of ozone coming from the back of one of the switchgear cabinets.This breaker provides power to a transformer and also a MV motor through a...
Where can I find a good book on different plumbing techniques for process measurement. I deal with mostly dry pressure and draft instruments and would like some info on the accepted ways of plumbing these devices. I've been tasked recently with designing new plumbing to eliminate some of the...
I'm working with a weighfeeder that uses a 3hp 180V 1750rpm DC motor controlled by a Bardac speed control. The Bardac always used tach feedback for regulation, and we have been instructed to remove the tach and switch the controller over to armature feedback. This weighfeeder regulated the...
I just replaced one of the DC drive motors on a cement kiln, and now there seems to be some sort of unbalance going on. The kiln is driven by two 75hp DC motors wired in series to an ABB DCS 500 controller. Power is transmitted through toothed Gates power belts, gear box, and a dual pinion...
I'm currently working with a ball mill driven by an old GE 1250hp 180rpm synchronous motor through a ring and pinion setup. Lately business has been slower than normal, and the mill sits for a week at a time. After sitting this long, it can't get up to speed and stalls before it can synchronize...
my plant was built in the late 50's and we have alot of old u frame motors still running. Most of the bigger fans have been replaced with T frame high efficiency motors, but there is still lots of U frames in service. Replacing the U's with a T takes alot of work, and I'm wondering if it is cost...
