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In another project we have an electrical room in which we have encountered breaker failures, we have verified the system condition at the time of failures ( system loading,etc) and found no issues. Enviromental elements were checked and due to the type of failures phase to phase and phase to...

We are have a large facility ( new) , this facility has multiple LV UPS systems made up of 750 kVA modules in parallel. We are experiencing failures of the main output breaker of the switchboard that consolidates the UPS outputs and of the load bank breaker. The occurrence has not been...

ASHRAE has taken the lead on data center design. They have a complete book on structural design for data centers

Tnkas DPC, when you state 9% at the bus? What do you mean. Is it a deviation at the output of the transformer of 9% and then 1% voltage drop at the motor feeder?

We have a project were the engineer has requested to modify our 21kV transformer taps in order to achieve a secondary voltage level of 510V. I know motors have rating of +/-10% so it should be Ok. However I would like to understand other impacts

Thanks. I am dealing with ABB drives

Thanks for all replies. My drives are to handle fan type loads between 10-40hp. I am reviewing manufacurer drives O&M books to find distance data,but nothing yet. I google the site but found limited data, still searching.

Is there any difference on locating VFD's close to their loads or can they be located +100' from their loads. I had read at one time that there was an issue when working with VFD'and the cable lenght,etc. Is this correct or is this no longer applicable with new generation VFD's

The system is using U/G tanks,the installation is a mission critical (7 x 24 operation) and the periods were we will be over +122F might be 3 weeks, but with operations above +111F for periods over 3 months. So the basis of design caals for fuel cooling, we are just looking for alternatives that...

We have some diesel units installed indoors within a building, this facility is located in areas with design day + 122F. So we would like to cool the fuel on the return path as to improve a bit our performance. Our project owner has asked us if the only way to cool the fuel is with a plate type...

I had a similar situation , the UPS were 500 kVA and the culprit was our low level of load within the space. When we load bank at specified loads it all went weel. The day we needed our low level (<50%) did not allow us to get the system sysnc

Thanks for all the help, I will try to put everything together as to "suggest" some of the items pointed out within these posts, even tough I will have to tolerate statements like : I will not be liable, against the plan of record,etc. All of this when I have what I would call an incomplete design.

Guys, I am not the design engineer, but the design engineers are stating that its the generator problem and viceversa. All of the documentation even of the gen set brochures state Active Synchronization, not passive. So what I am trying to get is an idea of the path we should follow to get...

The intertrip also assures that your operational staff has to reset and verify conditions on the LV side prior to energizing the HV side. You will be amazed on the amount of times operators will not verify conditions at both ends. They will check the XFMR conditions, OC relays on the High Side...

All , thanks for your input. After several meetings between gear vendor and gen-set vendor. This is what I can summarize: The specified and designed transfer system was intended to provide a closed transition from generator to utility power using a passive synchronization strategy. The concept...

The system uses a Main-Tie-Main Breaker arrangement controlled by a PLC. The generator is connected to one of the breakers.

Generally this means allowing the two sources to come in synchronization without forcing a change in the speed or voltage of one of the sources. Passive sync with the utility is often difficult since we normally want the softer(smaller) source to come in with a slightly faster frequency and...

Thanks I will be looking at the Basler site

davidbeach: Yep something like that is what I am told. I am still reaserching the web so I can seen how you modify the pasive to go active without spending my whole job budget.

Could someone provide some insight on the difference between active and passive synchronization. I have a project with closed transition were everything was designed around "pasive" synchronization and the Generator vendor is stating that they cannot do that and they only do "active"...