3000W Chinese Gensets Info.

professor95 wrote:

While your calculations may appear accurate, at higher ambient temperatures the ability to remove heat from the generator is reduced. Thus, it will run even hotter than your calculations at 100 degrees F outside.

That's not correct. My measurement made at 54 F directly scales to any other ambient temperature.

Have you ever seen the equation to calculate the junction temperature of say a transistor?

Tj = P * theta + Ta

Tj is the junction temp, P is the power dissipation, theta is the thermal impedance between the junction and ambient, and Ta is the ambient temp.

We can use the same equation to describe our gen. Instead of junction temp, we have some selected location on the gen. The equation shows if Ta is increased by 30F, the junction temp is also increased by 30F.

You don't need to wait till it gets to be 100F outside to to figure out the gen temp at 100 ambient.

BTW, after much searching I found Bob&cat temp data. His measured temps at 100 F ambient are very similar to my projected temps at 100.


So, at 100 dgrees you should back off on power (load) at least 30%, or to no more than 2,450 watts for a 3,500 watt rated genny.

Unfortunately that's about the only time I would consider using my AC.

BTW, you may find it interesting that the hottest temperatures I recorded are after the gen is turned off.

Over by the cast AL engine head, while it's running under 1500W load T=118F. After gen stops, temp increases to 172F. That's at 54F ambient. If it were 100 outside, the gen will get up to 218 F.

There's a problem with the thermal switch. It will do fine while the gen is running. But when gen is turned off, temperatures rise and the thermal switch could trip. It will take a while to reset itself. During that time we won't be able to start the gen.

On the fuel tank..... most all of these gennys, my Kipor included, must have a vented cap to work. If there is no vent, gas flow will stop. On the Chinese 3,000 watt class open frame models the tank WILL leak if sloshed around. The fix is to NOT fill it completely full so the baffel in the tank neck will keep fuel from splashing out. On my Kipor, there is a open and closed valve for the cap vent. Thus, it can be sealed for transport.