Power sag when turning generator off.... how dangerous to electronics?

[alyaz]

We have a Magnum inverter.  Although we generally try to manually turn the generator off when no electrical items are in use, there has been occasion that the generator will turn off and the lights (and if the TV were on it may even turn off) will dim before the inverter restores battery power.

So my question is, it is usually this ‘power sag’ that is so dangerous for electronics, right?  If so, should a person have a ‘surge protector’ like one of the “Progressive’ units to turn power off to an expensive fridge etc?

Thanks...

[Westbranch]

Sounds to me like the 'transfer switch speed"... is too slow

mine for Utility to Inverter is 16 - 50 msec,  faster in reverse Inverter to Utility, 8 - 10 msec

[alyaz]

Sorry, should have mentioned we are ‘off grid’, so no utility tie here...  Or am I not understanding you correctly?  Thanks.

[mike90045]

Actually, you need to check your Generator Qualification settings.
It sounds like as the generator slows down, it's still being held onto by the Magnum.
There should be settings for both Frequency and Voltage, as a window, of what is acceptable to the Inverter (or ]you)
Fq  55-65 Hz
voltage 220 - 250 VAC 
or something like that.
  Your eyeball can see even a small variation of voltage as dimming (I used to drive the Power Quality folks at my plant mad, I'd call them and ask, what happened?   Dropped 2 cycles as a transformer tap stuck or something.  They could not believe that I, sitting at my desk, can call and report stuff their gear didn't alarm on, and be right every time.)

What you NEVER want to have happen, is the loads to stay connected as the generator winds down and stops.  This will REMOVE the residual magnetism in the rotor, and it will stop generating.  There is a fix:
http://www.dieselduck.info/machine/03%20electricity/flashing_generator.htm

[Westbranch]

AL, in my case I am OG too, and 'utility' = Generator, stop gen and it switches to battery...

[Vic]

Hi Al,

Looking at the specs for the Magnum PAE Inverters,  they do "spec" 16 ms Transfer speed,   although there are no limits speced  (ie Max,  or Typical),   just that specs are at 25 C.

The Magnum inverter line have  a reputation of not being particularly fast at regulating voltage,  which could be part of the issue.

FWIW,   Vic

[alyaz]

Thanks for all the replies.

I do recall speaking to someone at Magnum a few years ago about this issue.  They told me there was an updated ‘board’ available that should help somewhat, but I think it was about $400 or something to that effect.

Regards,
Al