Inverters - whats the inside track?

[Boron]

Often, fridges and freezers have a special relay for start/run operation to switch the 2phase induction motor start run winding - so 3x might be a fair estimate. A DOL motor might be anywhere between 6x to 8x FL current thats the problem. Sometimes even an 800W microwave wont be supported - remember this modulates power by on/off switching of load

 

[Chispas]

so 3x might be a fair estimate

Thats good to know, now i need to find out the rated W for the appliances im looking at.
As an apprentice I did some time in the heavy fabrication workshop that had a guillotine that could cut 6mm boiler plate.The motor was about the size of a large beer barrel & it had a smaller motor attached to spin it up before throwing the breaker....soft start OG style.

 

[Hedges]

How long do these Multiplus last? any MTBF's figs assuming benign use. Anyone any experience with these softstart modules to use domestically?

By the way, an MTBF of say 100,000 hours does not mean expected life of one unit is 11.4 years continuous operation.

It means if you ship 100,000 units, the average number of failures in first hour is 1 (one).

Mean Time Before Failure, an average of failures over some number of units.

Life testing, HAST (Highly Accelerated Stress Testing) etc. is meant to get lifespan of hardware.


Heat and humidity are the enemy of electronics.

Heating of inductors and transistors is proportional to the square of current, so 2000W is 4x the temperature rise (not counting thermostat controlled cooling) of 1000W. Something similar for MPPT and inverter operation.