Your last generator Maintenance Run

[3930dave]

We had an outage Sunday with 19 family members here for dinner.
It was funny because one of them asked me how often we lose power, I replied not often enough then the majority of the house went dark except for my priority circuits which pass-thru my off grid battery backup.
I went into the powerhouse & fired up the 10hp yanmar threw 1 breaker and the whole house was powered up.
As others have said you would be surprised how little power you require with proper management and energy efficient Appliances & lights.
I built my system for mileage and currently get about 5+- hours/gallon.
If necessary I could be off grid a very long time.
90cummins

:thumbsup: Rgds, D.

 

[RoyKing]

learning curve about loads. The 36kva genset set shutdown, Deep sea controller watches everything. The logs showed over and under voltage, frequency, and current. About three hours in while still waiting for power Co to put the meter back in the over voltage crossed the limit setting. So that lead to investigation on the AC, Turns out the starting load is huge locked rotor is 150 amps. The settings on the controller were set for zero tolerance so when house load increased due cooking diner that threshold was crossed. So not have any real experience with the controller a deep read on the manual was needed. Turns out the limits have tolerance setting so I opened them from zero to five seconds. There was another setting called short circuit with Amp setting of 200 amps. with setting called Electrical trip IDMT or shutdown I change it to Shutdown from trip and raised it to 300 amps. Knowing that large motors look like short circuit at start up. Loaded the new config and as soon as the AC came on the gen shutdown, log showing short circuit. So more reading, turns out IDMT is power curve of time versus overload. The higher overload the less time it will allow a run. So tomorrow we will try the 5 second delay and Electrical Trip setting enabled. When we choose this particular Alternator I spoke with MeccAlte and the engineer explained the rotor construction. He recommend the model with iron core rather than the Aluminium explaining how the dedicated single phase iron core can handle loads better especially motor that start under a load like pumps. Who would have thought the surge from an AC that only draws 7k watts running would surge past 300A on startup.

 

[HarryVanderpool]

Who would have thought the surge from an AC that only draws 7k watts running would surge past 300A on startup.

Indeed.
One of the most overlooked, misunderstood design considerations is inrush current upon start-up.

 

[3Ts]

Indeed.
One of the most overlooked, misunderstood design considerations is inrush current upon start-up.

Even incandescent light bulbs have a huge inrush current of 15x rated current. It really is a short circuit since there is a metal (tungsten) filament between the terminals whose resistance increases as it gets hotter.

 

[LouNY]

You know a person has to wonder did the old timers have it right,
they used to switch the neutrals just as they had gotten used to switching the grounds
on the old Delco DC systems.
Is your in rush moderated by switching neutrals ? I'm not sure I haven't seen a discussion of it in a long time.
I do know that when hot wiring a loop the arc is less if the neutral is connected last.

 

[HarryVanderpool]

Is your in rush moderated by switching neutrals ?

No.
A circuit begins at the source, travels through the load, and ends at the source.
The "heating up" or energizing of the load requires the sudden inrush of current regardless of high or low switching.

 

[LouNY]

No.
A circuit begins at the source, travels through the load, and ends at the source.
The "heating up" or energizing of the load requires the sudden inrush of current regardless of high or low switching.

The majority of my experience that was not 3 phase motor loads was in DC,
there is a definable different load when the load was switched compared to the hot leg,
it did not matter if it was a positive or negative source.
The energy is mostly consumed in the load it doesn't matter if it's AC or DC.
Therefor your inrush could well be choked by the resistance and or inductance of the loads.

 

[Industrial Toys]

Sounds like elevator stories I hear about. Elevator has been in service for fifty years. Now a NEW digital one is installed and nothing but trouble, inconvenience and EXPENSE. The guy who works on it doesn't understand it. After all, he didn't design it.

 

[Fallon]

The electricity actually comes from the negative side in a DC system, not the hot or positive side. Electrons have negative charge, so the side showing negative has all the extra electrons that will go rushing towards the positive side.

 

[3930dave]

Who would have thought the surge from an AC that only draws 7k watts running would surge past 300A on startup.

Perhaps you can tune your controller further to support that AC...... if not, let's see what hardware based soft-start options for that AC show up here (cm, grs, ur, 90 et al.......... ?).

Rgds, D.