Modified vs. Pure Sine vs. Microwave...

[Osprey69]

We powered our 1500 watt microwave (refrig etc) with a Xantrax 1800 modified sine wave inverter.

Installed a Magnum 2000 watt pure sine wave and microwave now just immediately shuts down. No error codes. The refrigerator still works fine with new inverter.

When directly connected to inverter microwave still shuts down immediately.

So why would a modified sine wave inverter smaller power the microwave but not the newer, bigger pure sine wave inverter, except that there is a defect in new inverter?

But if the inverter is defective why would the household size frig run?

Thanks in advance.

 

[O C Diver]

I would check your programming. I'm assuming that you have the remote display for the inverter. This is where the programming is done. I believe (but don't quote me) that the low voltage cut out is programmable. There will be some DC voltage drop when running the microwave as compared to the refrigerator. The microwave probably draws 10 times the amps of the refrigerator. So if the voltage drop exceeds the programmed set point, this could be the cause of the problem.

There might be other possibilities, but that would be where I would look first.

Ted

 

[Iggy]

I would check your programming. I'm assuming that you have the remote display for the inverter. This is where the programming is done. I believe (but don't quote me) that the low voltage cut out is programmable. There will be some DC voltage drop when running the microwave as compared to the refrigerator. The microwave probably draws 10 times the amps of the refrigerator. So if the voltage drop exceeds the programmed set point, this could be the cause of the problem.

There might be other possibilities, but that would be where I would look first.

Ted

Yep!

Also I would make sure the outlet is wired properly.

 

[tiltrider1]

I think OC is pointing you in the right direction. Most likely your Magnum has been programmed to unrealistic parameters for voltage drop. It is also possible that there is nothing wrong with the Magnum and that you have undersized the wire between the battery and the Magnum which is causing an excessive voltage drop. Your older inverter might not have monitored voltage drop at all.

I like the idea of putting a multimeter on the outlet to see if the inverter is cutting power or if the issue is solely related to the microwave.