Why would a microwave oven not work properly on a petrol generator?

Andy From Sligo

The petrol generator is 2.8kw output - the microwave is 800w .

The clock comes on when plugged in , the lamp inside the microwave lights when the door is open . I put a glass of water in the microwave, close the door, press start on the microwave oven and the petrol generator pulses like its going to cut out the engine. I quickly unplugged it. but what was going on . The genny is 60hz and the microwave is 50hz …. has that any bearing on things?

topofthewind

Some appliances are more sensitive to voltage irregularities and voltage drop than others. If you are using a long extension lead, it could lead to a drop in voltage above the recommended limit of 3-5%. Using a thicker gauge cable can increase the acceptable cable length. Is the generator connected by a changeover switch?

L1011

The frequency is going to be a HUGE issue. Pretty much nothing except (some, not all) switched mode power supplies will work on 60hz. You're probably damaging everything you try on it.

How on earth did you even get a 60hz generator here?

topofthewind

I also read that microwaves rated for 800w actually draw more than that to operate.

Andy From Sligo

https://www.boards.ie/discussion/comment/123104769#Comment_123104769

borrowed it - the label says 50Hz - the digital energy meter i plugged in says its running at 60hz

Andy From Sligo

the generator is 2.8kw continuous - well capable to run it I should imagine

L1011

https://www.boards.ie/discussion/comment/123104824#Comment_123104824

Faulty then. 230/60hz isn't even common - its used in Brazil and a few other places.

Andy From Sligo

https://www.boards.ie/discussion/comment/123104765#Comment_123104765

no changeover switch needed its not powering the house - just has a 13a plug on it - just have it a direct connection to kerosene boiler - hope the 60hz is not damaging it, just trusted the label at 50hz - been running boiler, then i found my digital energy meter and plugged it in - only then did i see it report at 233v 60hz

EDIT: - I have a 11w CFL plugged into the genny too for a bit o light

Andy From Sligo

https://www.boards.ie/discussion/comment/123104844#Comment_123104844

Irish machinery Auctions were selling them a while back :

Deagol

https://www.boards.ie/discussion/comment/123104782#Comment_123104782

800w is the output of the microwave - typically an 800w microwave will use 1000-1100w operating.

Andy From Sligo

i wonder if these newer microwave ovens have a inverter whatever in them (magnetron is it?) I dont know the difference between todays microwave ovens and the older ones but could that be why the genny didnt like it? - I know this microwave oven dont make a bang like the older microwave ovens used to when the magnetron comes on inside

Andy From Sligo

I found my trusty socket wiring tester and decided to try it out on the genny - Live Neutral Reverse detected! 😯

so thats 60Hz and Live Neutral Reverse

Lenar3556

The 60Hz is an issue for a start, there is something wrong on the generator setup.

The socket tester result I would be less concerned about. It’s designed for use with a centre tapped transformer and the generator doesn’t have that, so it’s not going to give a correct result.

Those generators aren’t really suitable for electronic loads in any case. You would be better off with an inverter generator. Loncin do a half decent one at reasonable money.

Andy From Sligo

https://www.boards.ie/discussion/comment/123107023#Comment_123107023

ah right yes thats interesting about the centre tapped thing , thanks I never thought of that. - it being AC anyway its not DC so there wouldnt be any issues is there the same that if DC was reversed polarity , even if you wired a 13a plug to most electric/electronic equipment (even going through ac to dc power supply/charger) the live wire to the neutral and neutral wire to the live wire what are the consequences on that anyway being AC (alternate current) i mean you could even do that on the plug of a CFL or LED light and it would have no issues and the map will still work (or is that because they have a diode rectifier in the circuit?)

I have the generator running my devices at the moment plugged into 2 surge and spike arrestor 13a plugs - will that help or not have any affect?

10-10-20

Older microwave ovens (with large transformers) are inductive loads and will spike the genny on start-up. Newer microwaves did away with the heavy transformer, so they might play nicer on a genny.

This might be interesting to watch… Matthias got into a spot of trouble for this review:

https://www.youtube.com/watch?v=CPv4IUSyIPk

L1011

https://www.boards.ie/discussion/comment/123108286#Comment_123108286

Those won't make the power any cleaner; or deal with the frequency being wrong - they may protect something from a spike if the generator is continually inconsistent

Andy From Sligo

https://www.boards.ie/discussion/comment/123108343#Comment_123108343

no I didnt think it would correct the 60hz to 50Hz …. but I thought it might help with spikes and surges. Never mind.

i havent dared put our LCD TV and Sky+ Box on the genny yet, i dont want them getting ruined/damaged

L1011

https://www.boards.ie/discussion/comment/123108560#Comment_123108560

I wouldn't try either of them on it. TV might actually take 60hz, lots do, but is unlikely to like unstable output.

The Continental Op

https://www.boards.ie/discussion/comment/123104890#Comment_123104890

I have one of those under a different name. Its heading for the tip but its heavy and I've not got around to it. Keep thinking I might keep the petrol motor.

Long story as to how I got it for free, but the CE mark is fake the wiring is unsafe and the output is way out often putting out 400V AC.

Andy From Sligo

kerosene boiler is on it so we can at least have hot water and hot radiators (i dont know if 60Hz is like on grant euroflame outdoor boiler unit but its purring away happily and the central heating return pump in the boilers is pumping ok) - have wired up genny direct to kerosene boiler because i didnt want to back whatever they call it into the consumer box , just in case it shock an esb engineer or neighbour . and a 11w cfl bulb in living room running off it ok - and even though most probably not supposed to if it indeed has unclean power, have got laptop and phone and torches charging up off it too

L1011

Circulation pump motor may be running 20% faster than expected on 60hz. This is generally not a good thing for the pump.

Andy From Sligo

https://www.boards.ie/discussion/comment/123108637#Comment_123108637

I have kept my digital energy meter plugged in all the time on this one i been lent and then plugged the rest of thestuff through that to see also what wattge my stuff has been drawing from the generator, and its registered around a stable 233v AC - its just weird (and slightly worrying) that the energy meter is outputting 60hz (especially seeing as the label on the genny says 50hz) - never mind , if i hadnt had a energy meter hanging around i would be none the wiser lol , too much knowlege is a dangerous thing haha. I will just keep fingers crossed that we get through this long power cut and that when we have normal power supplied the genny has not damaged anything with its 60hz (either short tem or long term) - if it has I will cross that bridgethen. So far the advantages of borrowing this generator has far outweighed the negatives and at least have made life a little bit more bearable . I certainly am gonna look for a small cheap generator for myself for the future if this happens again just to have on on standby

The Continental Op

https://www.boards.ie/discussion/comment/123108904#Comment_123108904

The label on the genny isn't worth the paper its printed on. If it has a 220V and a 110V output then if the 110V output is 60Hz which it would be for America then the 220V side would also be 60Hz.

Andy From Sligo

https://www.boards.ie/discussion/comment/123108827#Comment_123108827

im keeping my fingers crossedc it be ok, if not i have replaced the central heating pump on our boiler before, only cost something like 40eur so didnt break the bank

smuggler.ie

As an emergency purchased DW8500W from DD(new, in the box) advertised as 8.5kW capable, knew its BS from the start, but beggars cant be …. - POS, but got me out for few days
12-15 hours continues run for 2 days = ~€20 petrol per day to run
output ~230-235V , frequency fluctuate 50-55Hz but allowing inaccuracy on my measuring tools
Ran of it freezer, fridge, x2 circulating pumps and one shower pump, few lights (up to 4, 11W each), 4G router, x3 8port switches(one PoE) and x2 AP's and of course charging phones/power banks/18V(3Ah, 5Ah) batteries for makita torch . Even managed to run my PC at same time :D

Problems i had:
once connected to house wiring(sure disconnect ESB side) with more-less all above devices - voltage drop to 205V, fridge didn't like it, didn't perform at all but survived.
at shower pump "kick-in" lights would flicker(obviously), imagine all other devices struggle too

After discovered V drop, reduced the load(devices) and got extension leads instead through-the-house wiring:
Freezer, fridge, x2 circulating pumps, chargers, few lights
Voltage fluctuate 220-229, frequency fluctuate less

Power restored just few hour ago - so far all appliances working OK

Need to lay down "emergency" wiring for future occasions.
Think genny-to-house connection wire was to thin, potentially leading to V drop(continental plug - all i had to hand was 1mm2 lead)

Genny - meh, might shop for a better one.

10-10-20

https://www.boards.ie/discussion/comment/123110296#Comment_123110296

Yes, that 1mm^2 cable didn't help with the V-drop anyway. You really needed 2.5 at a minimum. Did the cable heat up much, did you notice?

smuggler.ie

https://www.boards.ie/discussion/comment/123110464#Comment_123110464

monitored on first day run as was suspecting heat potential - none by touch . Genny ran in the workshop so - cold environment. checked in-house wiring where could reach - no heat by touch felt.
Wiring distance also could play a role - workshop-to-house run on its own ~ 30-40 m
Anyway, extension reel ~30m directly from genny to fridge + 2m from it to circulating pumps was 1.5mm - no heat and V drop minimal.
Another extension reel from genny ~10m to freezer (again 1.5mm) - same "satisfactory" result.

One thing for sure - generator i got is not capable to provide for entire house, but might cover few "must have"

And need to run something like 4mm link(s) of independent wire from home to designated generator location , to be ready-to-plug.

PixelCrafter

as per above, microwaves are highly sensitive to supply frequency.

230V 60Hz is only used in Brazil and South Korea. That generator shouldn’t be on the Irish or EU market at all — nowhere in Europe uses anything other than 230V 50Hz power.

Anything with a switch mode power supply like electronics etc won’t care, nor will heating appliances, but some appliances may behave very oddly - wouldn’t suggest running the washing machine or dishwasher etc on that — could cause some issues…

Also boilers and pumps potentially have synchronous AC 50Hz motors. Could get some very odd behaviour from the central heating!

Same with fridge compressors — might run fast.

PixelCrafter

https://www.boards.ie/discussion/comment/123108966#Comment_123108966

Usually the 110V side is for British / Irish handheld work site tools, which are 110V 50Hz (normally with a two lives out of phase — centre tapped, so it’s about 55V from either side to earth). Unlikely to be intended for US 120V 60Hz appliances tbh.

john jameson

HI all !!

I was considering the purchase of a genny going forward as one doesn't know when we might find ourselves with out power in the future but I'd like to ask the question for feedback!!

If I only want to recharge a few camping lights charge phones and kids tablets would a 12v power inverter from the van do the job?

Iv a berlingo 1.6 diesel and don't mind having it idling for an hour or so to charge stuff?

Andy From Sligo

https://www.boards.ie/discussion/comment/123108328#Comment_123108328

yeah my microwave oven (samsung) I think is one of those ones with the heavy transformer in it