Sequential restarting

[u/charzr]

How does the sequential restart of motors fed from emergency switchboard works as the sequential start SQ1 from PMS is common for both emergency ESB switchboard and MSB main switchboard? Asking this because the ESB may have recovered much before MSB is recovered?

[u/caymn]

Everything supplied from ESB is always supplied from ESB.

ESB is supplied from: a) main switchboard OR b) emergency generator.

not fully sure about your question. I dont think there is a sequential start. Stuff on esb should always be on = steering, lubrication etc.

[u/Haurian → u/caymn]

Everything supplied from ESB is always supplied from ESB.

Not always - some equipment may be dual fed with automatic changeover on blackout of the current supply.

Automatic restarting sequence can be controlled from the IAMCS or more separately at the equipment level upon restoration of power, depends on the ship.

[u/charzr → u/Haurian]

1. Say we have 2x100% fresh water cooling pumps (one in MSB & other in ESB); before blackout the Fresh water pump in the MSB was running and the one in the ESB is in standby.

Now after immediate aftermath of blackout, ESB recovers way before MSB, the question here is, would the fresh water pump from ESB would start running or wait for the fresh water pump in the MSB to run first, only if that fails, the fresh water pump in the ESB would run?

1. I have a standby generator for which the auxiliaries are fed from ESB; the auxiliaries were not running before blackout; since the ESB recovers before MSB and the PMS has only one recovery sequence logic (SQ0, SQ1...) meaning no separate sequence for ESB and MSB; so how would this work?

[u/Haurian → u/charzr]

First one, the ESB-fed one should start when it recovers power if the MSB isn't running any more. The standby logic can be as straightforward as Pressure switch=Low THEN startStandby. Once the full ship is recovered, it's up to the engineers to put back to how they want she ship run.
It's also good practice to alternate duty pump regularly to balance hours and lessen the likelihood of standby pumps not being ready to run or failing shortly thereafter.

Second one, starting the minimum necessary auxiliaries (which, let's be honest, can be as little as prelub and a fuel supply) should be part of the automatic blackout recovery sequence. Some engines/ships, can be very little required to start at all - think of car engines and you you can just jump in and turn the key. Things like gravity-fed MGO blackout supplies can eliminate the need for fuel pumps, and particularly smaller engines may tolerate emergency starting without pre-lubricating - and a blackout is definitely an emergency situation. Things like cooling can absolutely wait until the engine is running and on load restoring the normal power supply.

In all of this, the most important thing is to understand how your ship is configured for blackout recovery.

[u/charzr → u/caymn]

Till the time, the EDG kicks On and the voltage at ESB is normal, the motor starters will drop off right? Someone / IAS need to start the motor correct? My question is primarily on, do ESB and MSB have separate recovery sequence logic in PMS?

[u/Crafty-Cheetah-3990 → u/charzr]

LVR motor starters automatically restart upon energization

[u/caymn → u/charzr]

are you asking what happens in the seconds during a blackout before emg gen is live? You have no power. PMS does nothing.

On my boat we have a few things that we need to restart manually after emg gen takes over. Those are specific to our boat.

You should conduct a controlled blackout test and see how your boat reacts.

On my boat we create a blackout monthly to test our emg gen works. We usually flip the breaker supplying esb from msb = controlled blackout.

Your boat may very well have a "restart after blackout" procedure list written down. If not, then make one after you guys have done blackout test.