A customer is requesting for backup feed from another circuit to feed their facility in the event of a sustained outage. This entails installing an automatic open transition rollover switch tying two circuits together. If their primary service goes out, then the switch will automatically...
dpc, closing the delta at high voltages have proven to cause ferroreasonance; therefore, from my understanding, most utilities do not close the delta at higher than 25 kv. The measurements were based on a recorder that is currently installed at the service and the bank is loaded. No specific...
thanks davidbeach.
Unfortunately, I don't think the customer will be too happy if I told him the high voltage on the hi leg doesn't matter. :) Do you have any suggestions on how to achieve a 120 degree separation between the two transformers?
I hope I can get some assistance on this problem....
A customer with 3-ph open delta 120/240 V is having high voltage on the hi leg of 220 volts, which exceeded the +5% limit of 208V. The two primary side phases of the transformer are balanced. The primary voltage is fairly balanced at 123...
Thanks David.
If the cable/tv pedestal is bonded to the case ground of the URD transformer, then would that be considered as bonding to the power system ground? Also, could the bonding to the case ground cause damage to the cable/tv equipment if the transformer faulted? Thanks.
I was wondering if the cable/tv pedestal was bonded to a URD transformer, and if there was a line-to-ground fault at the URD transformer... then will the the cable/tv pedestal see the fault as well?
Thanks!
The arresters are connected line to ground and I don't think the arresters operated. The utility monitored our service for a different issue in April and it showed that there was a 20% increase in voltage on one of the phases. We don't know when our surge protector was damaged so don't know...
My supervisor is complaining that the utility's substation breaker operations fried the surge protector on our 480V line. Is that possible? If so, what are our options in mitigating it? Thanks.
Thanks, ScottyUK... the thread was very informative. However, will installing a UPS upstream of the motors protect the motors from tripping on voltage spikes?
I have a customer that's been complaining that their VFD's been tripping offline due to voltage spikes, and it was determined that the spikes or transients were from the switching online of a nearby capacitor bank. What are the different options the customer have to protect his VFD's from...
From a utility's standpoint, what are the advantages of having customers install a recloser vs a fuse as their main protective device?
We are required by the utility to install a recloser to protect our primary meter service and the added cost for installing a recloser as opposed to fuses is...
We have an RPM monitoring device installed at our substation and it is recording a positive and negative DC offset but only in the neutral current. What can this indicate?
We are trying to identify the source of the votlage sags on the circuit that may be caused by a customer that is...
What is considered the average or normal voltage drop from my meter to my breaker panel? I understand the ANSI standard range for service voltage at meter is 114-126V and 110V minimum at the receptacles, but what is % voltage drop should one expect at the main breaker panel? thanks!
Can someone please advise where in the NEC does it state that a customer's ground have to bond with the utility's? Our facility is receiving 12kV distribution voltage and was informed from our utility that we have to utilize their system neutral as a bond to our equipment ground.
