Why won’t my Champion C46540 generator run the microwave?

[tonyclifton]

I have a 1300W microwave (120v) I’m trying to run using my Champion C46540 but the microwave shuts down about 5 to 10 seconds after I turn it on.

I know the generator isn’t overloaded running other stuff. It is lightly loaded running a few led and cfl lightbulbs. It runs a fridge and more lights and coffee maker just fine, although was not running any of these when the microwave kept shutting down.

I’m using the 4-prong 30R receptacle to power the breaker panel. At only 1300W the microwave should run just fine. What’s going on?

[2112]

enblethen wrote:
Many of the gensets have power to all receptacles. No selector switch.

But this one doesn't. It's either 120 OR 240. Can't have both at the same time. The schematic says so.

[enblethen]

Many of the gensets have power to all receptacles. No selector switch.

[2112]

Yea, its shown in the illustration on page 5 but no mention of it in the operation section.

Step 2 in "Connecting Electrical Loads" on page 10 is misleading as well. It implies both 120V and 240V connectors will have power at the same time. They don't.

[enblethen]

I must be blind in that eye! Thanks. Wonder why I didn;\'t see it farther in manual, must be blind in that eye! You would think that it would show on page 6.

[2112]

enblethen wrote:
2112: where did you find photo you posted?

From the cover page of the manual you provided. I enlarged it. Open the manual. That picture

[enblethen]

Interesting it is shown in parts but not shown in the control panel. It is also not the the operational control panel information.
2112: where did you find photo you posted?

[2112]

enblethen wrote:
I do not see a switch on this genset to change voltage ouputs. Only switches are the circuit breaker push buttons.
Genset manual

Toggle switch, item 58 on the parts list

[enblethen]

I do not see a switch on this genset to change voltage ouputs. Only switches are the circuit breaker push buttons.
Genset manual

[2112]

Gdetrailer wrote:
... partial credit for the nice diagram though

Thanks
I missed one orange line and didn't bother correcting it. I left a switch blowing in the breeze. I got the point across without it

[Gdetrailer]

2112 wrote:

Gdetrailer wrote:

2112 wrote:
......
......
You can get a regulated 120V 3500W using the TT30A connector, but ......

Your close, but not quite correct.

When the switch is set to 120V only, both 120V windings are connected in parallel. This means that not only all of the 3500W is available on the 30A RV outlet but the voltage of both windings are fully regulated by the AVR.

First sentence of last paragraph covered that. Maybe it wasn't clear enough? Do I get partial credit for using less words?

No credit for way too many words in the post of yours I quoted, partial credit for the nice diagram though :B

And, yeah, the OP is not the first or last to get bit by this 120/240 combo thing..

[2112]

Gdetrailer wrote:

2112 wrote:
......
......
You can get a regulated 120V 3500W using the TT30A connector, but ......

Your close, but not quite correct.

When the switch is set to 120V only, both 120V windings are connected in parallel. This means that not only all of the 3500W is available on the 30A RV outlet but the voltage of both windings are fully regulated by the AVR.

First sentence of last paragraph covered that. Maybe it wasn't clear enough? Do I get partial credit for using less words?

[2112]

I performed one more test before I switched back over. I replaced the 600W pot (590 something measured) with a 1140W measured space heater on L2.

MW & Heater ON, L2-122.4V 59.2Hz
I didn't bother measuring L1

[Gdetrailer]

tonyclifton wrote:


My microwave is an inverter style, or at least says so on the front.

If this is an inverter MW, try lowering your power level setting on the MW.

Inverter MWs use a switching power supply instead of a transformer to power the magnetron tube. The advantage is they can simply reduce the voltage going to the magnetron which reduces the power drawn from the AC mains.

This is different from non inverter style MWs which had a big heavy transformer which the voltage to the magnetron could not be reduced and what was done for lower power levels was to turn on and off the magnetron in bursts (Full on then off, full on then off), changing the amount of time on verses the amount of time off.

The downside of lowering the power level is it will act like a lower wattage MW and take much longer to heat things up.

Try half power then work your way up towards 100%, you might find that 70%-80% may work OK.

Barring all that, if you are looking for a replacement gen, your going to need to get at least a 5,000W 120/240V gen and that is the absolute bare bottom which would supply 20.8A on each 120V leg which just may be enough to run your MW as wired now.

Personally, I would recommend for whole house setup, 6,500W would be a much better setup which would not require as much load managing Basically giving you 27A per 120V leg..

I run a 9000W gen on my whole home backup gen which at first I thought was overkill, but it handles my deep water well pump plus other high draw items at the same time very well.

The downside to bigger is they use more fuel and they are one heck of a lot noisier.

[2112]

I decided to connect my generator to the house and simulate what OP is describing. Mine is a model 64514, similar to his. What I found really doesn't surprise me, but good to know, and not good.

With typical loads: fridge, TV, satellite receiver, satellite internet modem and router, charging 1 phone and 1 laptop.

All measurements using Kill A Watt P3

L1-123.4V
L2-120.6V
60.6Hz

1200W Microwave on L1, 600W coffee pot on L2.
NOTE: MW is specified as 1200 working watts. The P3 flashes 1700 during operation, indicating the actual load is greater than the P3 1500W rating. However, 8oz of water was placed in the MW. MW was operated for 30sec during each test and operated as expected. The water warmed up each time.

Coffee pot ON, L1-123.4V, L2-117.8V 60.3Hz
MW & pot ON, L1-120.6V, L2-126.5V 59.8Hz

Now here's the kicker
Just MW ON, L1-120.6V, L2-133.2V 60.4Hz

With a heavy load on L1 and little load on L2, L2 goes over 130V

End of Test



Yea, I'm bored