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  1. bytebyte

    Automatic Rollover Between Two Different Voltages

    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...
  2. bytebyte

    High Voltage on Hi Leg

    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...
  3. bytebyte

    High Voltage on Hi Leg

    The service is fed from 35 kV so closing the delta is not an option. Any other suggestions? Thanks!!
  4. bytebyte

    High Voltage on Hi Leg

    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?
  5. bytebyte

    High Voltage on Hi Leg

    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...
  6. bytebyte

    Fault at URD TRF and Cable/TV Pedestal

    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.
  7. bytebyte

    Fault at URD TRF and Cable/TV Pedestal

    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!
  8. bytebyte

    breaker operation frying surge protector?

    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...
  9. bytebyte

    breaker operation frying surge protector?

    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.
  10. bytebyte

    Voltage Transients Tripping VFDs

    Thanks, ScottyUK... the thread was very informative. However, will installing a UPS upstream of the motors protect the motors from tripping on voltage spikes?
  11. bytebyte

    Voltage Transients Tripping VFDs

    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...
  12. bytebyte

    recloser vs fuses

    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...
  13. bytebyte

    DC Offset at Substation

    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...
  14. bytebyte

    Voltage Drop from Meter

    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!
  15. bytebyte

    NEC Grounding

    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.
  16. bytebyte

    200hp Motor Doesn't Have Enough Torque?

    A customer has a 3-ph 200hp motor rated 440V. The customer is fed from 3-167 kVA transformers at 277/480V. Full Load Amps of motor is 257A and he does not have info on Locked Rotor Amps or Letter Code. The customer claimed the 200 hp motor did not have enough torque to get past the initial...
  17. bytebyte

    Powersave 1200

    I failed to mention that this is a small commerical customer with a demand meter that measures kVA usages. So the customer is being billed for kVA usage. From reading the replies, this powersave device can lower his utility bills by correcting his power factor; hence reducing his power...
  18. bytebyte

    Powersave 1200

    A customer inquired about using Powersave 1200 to reduce his electric bills by 25%. Has anyone heard of this and know how accurate this device is? Apparently, it just requires plugging in to the breaker panel. Can someone please explain how this device operates and how it is able to reduce...
  19. bytebyte

    Reversed Polarity on Closed Delta Bank

    What effects will reverse polarity have on a closed delta bank? Will the adverse effects on equipment be instantaneous or over a period of time?
  20. bytebyte

    Voltage Loss on Delta Service

    You're right, jghrist. The graph from the monitoring device has 3 channels which would typically represent the 3 phases. Channel 1 measures A-B voltage, Channel 2 measures B-C and Channel 3 measures C-A. Therefore, Channel 2 is measuring 320V, Channel 3 is 250V and Channel 1 is 480V. Thanks.

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