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Mark V shutdown
- Thread starter grajesh
- Start date
G.Rajesh,
As long as you don't just "kill" the power to the Mark V Speedtronic by opening the 125 VDC breaker without first opening the switches in the <PD> core, the order of power-down is not important. Note, that all of the motor starters which are controlled by the Speedtronic panel should also be de-energized, because most of the motor starter outputs are drop-out-to-run so when the relays are de-energized as the panel is powered-down they will be trying to start the motors! This can--and has--caused many a plant to go black (because of the high inrush current experienced when many GT auxiliary motors are all started at once).
And, when powering up, the same holds true--all of the switches in <PD> should be open before closing the 125 VDC power supply to the panel. However, for <C> to get to I/O Status A7 at least one of <R> or <S> or <T> must also be at I/O Status A7. So, you should probably power-up <T> then <Z>, <S> then <Y>, <R> then <X>, and then <C>.
If the panel has a DACA (or two) that is(are) normally powered by AC, it(they) should be de-energized first during the power-down process (before any of the cores/processors and before removing the 125 VDC), and last when powering-up (after the 125 VDC has been restored and all of the processors are at I/O Status A7).
You should also be cognizant of any signals/information going to any DCS or other control system that may cause alarms, etc., when the Speedtronic is powered down. This, too, has caused many problems for many sites when powering-down a Speedtronic panel.
As long as you don't just "kill" the power to the Mark V Speedtronic by opening the 125 VDC breaker without first opening the switches in the <PD> core, the order of power-down is not important. Note, that all of the motor starters which are controlled by the Speedtronic panel should also be de-energized, because most of the motor starter outputs are drop-out-to-run so when the relays are de-energized as the panel is powered-down they will be trying to start the motors! This can--and has--caused many a plant to go black (because of the high inrush current experienced when many GT auxiliary motors are all started at once).
And, when powering up, the same holds true--all of the switches in <PD> should be open before closing the 125 VDC power supply to the panel. However, for <C> to get to I/O Status A7 at least one of <R> or <S> or <T> must also be at I/O Status A7. So, you should probably power-up <T> then <Z>, <S> then <Y>, <R> then <X>, and then <C>.
If the panel has a DACA (or two) that is(are) normally powered by AC, it(they) should be de-energized first during the power-down process (before any of the cores/processors and before removing the 125 VDC), and last when powering-up (after the 125 VDC has been restored and all of the processors are at I/O Status A7).
You should also be cognizant of any signals/information going to any DCS or other control system that may cause alarms, etc., when the Speedtronic is powered down. This, too, has caused many problems for many sites when powering-down a Speedtronic panel.
G
G.Rajesh
Thank you CSA for the prompt reply
G.Rajesh
G.Rajesh
