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Most reputable three phase ATS control boards sense loss of phase, if the ATS did not switch then the voltage was in range based on the settings input by the technician. I would check to see what the settings are on the UPS and why it transfered without activating the generator start on the ATS...

LED lights work fine when sharing linear loads however when sharing nonlinear loads they stop working on three phase multiwire branch circuits. The voltage wave form is beautiful however the current wave form becomes a mess with nonlinear loads which the LED lights do not seem to like. Any...

Thanks ScottyUK, I reviewed the information on the tragic Grenfell tower fire. It seems to have started from a bad neutral connection on the back of a refrigerator. The refrigerator had plastic backing which burned and ultimately resulted in the exterior flammable cladding catching on fire. Why...

I managed to download the LCP (Lighting Control Panel) relay information just before the failure occurred, Eaton Cooper controls tech support says the cause is a voltage surge and cannot provide any other information. All circuits are protected by 277V, 20A industrial bolt on breakers, any...

IoT Technology Microgrids in smaller networks with a lot more interaction between customer and utility. Con Ed is trying to do it before the customers do it - good move from them.

The item on the enclosure floor is the power pack (switch pack) that is usually installed further away connected to a motion sensor by the light fixtures. Sorry for the confusion, I added the item in the enclosure for the photo. The debris on the enclosure floor is the insulation paper backing...

Thank you - I think the culprit is the power pack (switch pack) in the lower right corner of the photo. That seems to have overheated and created a ground fault which "somehow" blew up the LCP, maybe the fault rating of the switches in the LCP are not rated for that amount of fault current...

Any idea how a burnt up plastic power pack for a string of 277v LED fixtures can burn up half the relays in a lighting control board and then trip multiple 20A circuits and the 200A main. I am thinking bad design - breakers should be after the lighting control board, especially if they are...

The problem is that in this age and time most everyone wants to control their life with their phone. Gas, solar and wind is something they can control without too much hassle. It is only a matter of time before you have a micro grid around every block providing DC exactly as Edison dreamed of...

Hi Bill, your posts are great. You mentioned a very interesting datum earlier on the transformer acting as a series impedance for motor starting. Would this in any way shorten the life of the transformer if used solely for this function?

Can the specs of the oil be changed to increase the MVA of the ONAN?

Transformers always vibrate and make noise - how to make it less is an installation problem. Look for loose bolts and even the common error of installing rigid metal conduit to and out of the transformer unit instead of metallic flex.

It is an adjustable settings unit on usually larger or MDP (Main Distribution Panel) molded circuit breakers that can be adjusted for the following situations: 1) Enables coordination settings (based on engineered studies) with the downstream breakers so if there is a fault downstream the...

Is there a "special" motor repair hammer?

If you feel confident you can take apart the electric motor and clean the surfaces of the stator and rotor. You probably got it wet and rusted a little just enough to prevent it from starting to spin. I have seen this on pump motors where it seizes up after prolonged time of heavy water...

Okay located two issues on the operation of the washer unit. 1) Bad speed sensor for the drum occasionally stopping wash cycle. 2) Users resetting unit and skipping cycles to get to the assumed last wash cycle after unit shutdown. Point 1 is what jraef mentioned which I assume could create...

You are correct parallel for adding resistors, the overheat safety switch was in series - mixed it up. Good advice on grossly over estimating the braking energy to be dissipated. Thank you.

Air flow is okay, fan in compartment is working. Could try to cheat by adding an additional brake resistor in series to the ones that are there to reduce the heat, but I would prefer not to do so as that is not the original spec.

Hello, what mechanical issues can create VFD brake resistors to overheat and short that is not related to the actual programming or VFD. Had to replace the resistors twice recently on an industrial 480V washing machine motor, before I go ahead and replace the VFD it would be helpful to get some...