Generator AC on/off and Inverter drop out issues.

machineman

So its winter time and I have to turn my generator on now and then to boost my off grid system. Problem is when I disconnect the generator AC power(L1,L2 220V) from the Magnum MSAE4024 inverter/charger there's a very quick on/off cycle from the inverter ouput which effects every device in my house. Of course this means blinking clocks and other things that need to be restarted. So the Magnum is already inverting and when the generator power is shut off the inverter cycles on/off in <1sec. Its annoying and probably not good for some sensative computer electronis. Any seggustions to prevent this inverter drop out?

Thanks.

Cariboocoot

Re: Generator AC on/off and Inverter drop out issues.

Okay "Magnum guys" any answers?

Outback's have programming for how many cycles before picking up the gen, but the transfer is not noticeable.

There may be something in the programming along the lines of "transfer time". Really the changeover should be instantaneous.

NorthGuy

Re: Generator AC on/off and Inverter drop out issues.

May be that will help (from MSAE docs):

The transfer from Standby mode to Inverter mode occurs in approximately 16 milliseconds.
While the MS-PAE Series is not designed as a computer UPS system, this transfer time is usually
fast enough to hold them up. However, the VAC dropout setting has an effect on the ability of the
loads to transfer without resetting. The lower this setting, the longer the effective transfer will be
and therefore, the higher the probability for the output loads to reset. This occurs because the
incoming AC voltage is allowed to fall to a level that is so low, that when the transfer does occur
(in addition to the relay transfer time) the voltage on the inverters output has already fallen low
enough level to reset the loads.

solarvic

Re: Generator AC on/off and Inverter drop out issues.

Do you have the remote control for inverter? I have the 4024 ae model and think the setting would be the same as the PAE model. I don,t have a generator but use gid for charging the battery. With mine set at ups mode it doesn,t drop anyrhing if I shut off the power from the grid. VAC dropout can be set UPS mode and below rhat setting 100 vac down to 70 VAC dropout. The highest VAC dropout you can use shortens the transfer time on your inverter. The lower settings is for generators with poor stability power output. Good argument to have a high quality generator. I would try the highest inverter setting that your generator will accept without generator dropping out. With the ups setting on my inverter it will transfer without the computer crashing and the geo spring waterheater don,t crash even with all the other loads running. :Dsolarvic:D

machineman

Re: Generator AC on/off and Inverter drop out issues.

I have the 4024 AE magnum as well with the MERC remote. I will check for a UPS or voltage dropout setting. The thing is that the inverter is always inverting. Just gets interupted for <1sec when I shut the gen off. I control the gen manually and it doesn't do it when I turn the gen on, only off.

Cariboocoot

Re: Generator AC on/off and Inverter drop out issues.

machineman wrote: »

I have the 4024 AE magnum as well with the MERC remote. I will check for a UPS or voltage dropout setting. The thing is that the inverter is always inverting. Just gets interupted for <1sec when I shut the gen off. I control the gen manually and it doesn't do it when I turn the gen on, only off.

Okay, the thing there may be that (if you aren't doing so) you need to disconnect the AC from the gen first before shutting it down. The Outbacks will do this too; if the gen 'winds down' there's a lowering of AC Voltage to loads that can cause them to trip out before the inverter itself reacts.

If you are disconnecting the AC 'clean' before turning the gen off this power 'blip' shouldn't happen.

machineman

Re: Generator AC on/off and Inverter drop out issues.

I built my own gen start box. It has 2 modes, Gen on/off and Gen AC on/off. The off sequence is, Gen AC off via a 50A contactor(this should be a clean disconnect). Then I wait a few seconds to turn off the generator. The blip happens when the contactor disconnects the AC while gen is still running. I will be up at the cabin site in a week and will check the following:

--Magnum VAC drop out settings and the possibility of this UPS mode??
--Measure the Gen VAC during the contactor disconnect.

NorthGuy

Re: Generator AC on/off and Inverter drop out issues.

machineman wrote: »

Gen AC off via a 50A contactor(this should be a clean disconnect).

It depends on how Magnum detects the generator voltage. Since AC is always changing, the microcontroller has to take lots of readings and then do lots of calculations to correctly calculate true AC voltage. They may save money by converting AC to DC and then measuring DC, which is much easier. If this is the case, the abrupt disconnect may appear to Magnum as a gradual decrease in voltage. It may be very fast, but still enough to kill the computers.

SolaRevolution

Re: Generator AC on/off and Inverter drop out issues.

From the MS-PAE manual (2009) :

"3.2.2 Transfer Time
While in the Standby Mode, the AC input is continually monitored. Whenever AC power falls below
the VAC dropout voltage (80 VAC per leg, default setting), the inverter automatically transfers back
to the Invert Mode with minimum interruption to your appliances - as long as the inverter is turned
on. The transfer from Standby mode to Inverter mode occurs in approximately 16 milliseconds.
While the MS-PAE Series is not designed as a computer UPS system, this transfer time is usually
fast enough to hold them up. However, the VAC dropout setting has an effect on the ability of the
loads to transfer without resetting. The lower this setting, the longer the effective transfer will be
and therefore, the higher the probability for the output loads to reset. This occurs because the
incoming AC voltage is allowed to fall to a level that is so low, that when the transfer does occur
(in addition to the relay transfer time) the voltage on the inverters output has already fallen low
enough level to reset the loads.
The disadvantage of a higher VAC dropout setting is that smaller generators (or large generators
with an unstable output) may nuisance transfer. This commonly happens when powering loads
that are larger than the generator can handle - causing the generator’s output to constantly fall
below the inverters input VAC dropout threshold."



Have you noticed any difference in the duration of the on/off cycling depending on how hard the system is charging before the generator is turned off? IE. Is the problem any less if you turn off the charger before turning off the generator?

-Alex

niel

Re: Generator AC on/off and Inverter drop out issues.

actually, that is quite fast to begin with as 16 milliseconds is about 1 cycle of the ac waveform. even if you sacrificed several more cycles it should not matter, but a generator stopping too slow could put out a lower ac voltage at a lower frequency for some time so the answer would be to set the dropout voltage point to maybe 100vac. now one possibility may be that your contactor (assuming a relay) in your ags could be bouncing and it is hitting the opposite end and bouncing back making brief contact again. the magnum detects a disconnect quite fast and then you are shoving more ac at it through the bounce in the relay before finally going off. it surprisingly may be confusing the magnum because of the magnum speed in switching and detection. the higher voltage setting should help, but if it does not cure it then you may need to obtain a better relay.

vtmaps

Re: Generator AC on/off and Inverter drop out issues.

machineman wrote: »

I built my own gen start box.<snip> The blip happens when the contactor disconnects the AC while gen is still running.

niel wrote:

but if it does not cure it then you may need to obtain a better relay.

Your relay must be a 'break before make' type. If its not, that could be the problem.

--vtMaps

PhilS

Re: Generator AC on/off and Inverter drop out issues.

Raise the 'drop-off' voltage as SolarVic recommended. I have Magnum inverters and found doing that solved the "wink" problem with my sat receiver and TV. I can give a more detailed answer if you need, but I gotta cut it short now.

Phil

machineman

Re: Generator AC on/off and Inverter drop out issues.

SolaRevolution wrote: »

From the MS-PAE manual (2009) :


Have you noticed any difference in the duration of the on/off cycling depending on how hard the system is charging before the generator is turned off? IE. Is the problem any less if you turn off the charger before turning off the generator?

-Alex

It also happens with turning the charger off before turning off the gen AC. I will play with it next weekend and post back