Events

PCIC Europe

May 6-9, 2019
Paris, France

 

PCIC Europe is the premier conference for the exchange of electrical and automation experience in the oil & gas, chemical and pharmaceutical industries, covering all the aspects of the upstream and downstream activities.

Event Details

 

Pullman Centre Bercy Hotel
1 Rue de Libourne, 75012 Paris, France

  • Monday, May 6, 2019
    • 6:00 PM-9:00 PM
  • Tuesday, May 7, 2019
    • 8:30 AM-6:00 PM
  • Wednesday, May 8, 2019
    • 8:30 AM-6:00 PM
  • Thursday, May 9, 2019
    • 8:30 AM-Noon

 

Meet the Experts from Beckwith Electric

 

Don’t miss your opportunity to meet with Beckwith Electric’s subject matter experts to discuss applications and view product demonstrations.

Pullman Centre Bercy Hotel
1 Rue de Libourne, 75012 Paris, France
10th Floor

  • Monday, May 6, 2019
    • 6:00 PM-9:00 PM
  • Tuesday May 7, 2019
    • 4:00-6:15 PM
    • 8:30 PM-Midnight
  • Wednesday, May 8, 2019
    • 4:00 PM-9:00 PM

 

Beckwith Technical Presentation


Motor Bus Transfer Applications, Issues and Considerations

  • Tuesday, May 7, 2019
  • 10:45 AM-12:15 PM
  • Parallel 1/2
  • Room: 263
  •  Presenters:
    • Mohamed Abdel Khalek
      Middle East Sales, Beckwith Electric

This technical paper explores the following research:

  • Residual Voltage Transfers always thought to be safe even if completed out-of-phase, can cause significant torques on motors, exceeding a 3-phase fault at the motor terminals.
  • IEEE C37.96 identifies events that occur or conditions that exist prior to and during transfer where, at transfer initiate, the initial phase angle may be nowhere near zero!
  • So at the end of a Residual Voltage Transfer spin down, the close phase angle may be nowhere near zero!
  • Research with modeling motors during transfer has proven that in 40% of the cases closing at varied angles, the peak-to-peak torques developed during the Residual Voltage Transfer are higher than the 3-Phase Short Circuit Torques of the motors on the bus.
  • This research has revealed that the peak currents in motors during Residual Voltage Transfers are higher than the 3-Phase Short Circuit Currents in more than 60% of these cases.
  • This motor modeling research also shows that in 89% of the cases closing at varied angles, the currents during Residual Voltage Transfer are in excess of six times rated current.
  • Synchronous In-Phase Transfers may take longer than some arbitrary time limit. Depending on the initial phase angle at transfer initiate, it may take more than 6 or 10 cycles for the motors to rotate back into synchronism.
  • Compared to blind Residual Voltage Transfers, these Synchronous In-Phase Transfers are much faster, closing at much higher voltages, at much lower slip frequencies, with closure near zero degrees and low inrush current and torque.
  • The 1.33 resultant pu V/Hz transfer criterion in NEMA MG-1, ANSI/NEMA C50.41 and IEEE C37.96 has no correlation to motor torque and actually gives passing grades to severely excessive torques upon transfer.
  • Time period transfer criteria, stated in NEMA MG-1, IEEE 666, ANSI/NEMA C50.41 and IEEE C37.96, are arbitrary and would permit severely out-of-phase transfers or conversely may preclude perfectly good synchronous transfers.
  • A Motor Torque Ratio TPK /TL, introduced as the aggregate peak torque at transfer expressed as a multiple of the aggregate load torque prior to transfer, displays a high correlation to the phase angle at transfer with little effect from voltage or frequency difference.
  • If it is torque that reduces the life expectancy and damages motors or driven equipment, or both, as suggested in the C50.41 Standard, then the industry must use a torque-based criterion to assess if transfers are being completed within acceptable torque limits.