Ah Mike, but I did specifically talk about synchronous machines! As it happens I do have a small generator of the asynchronous kind, but to be honest (and as I said) it is not very good at either constant frequency or constant voltage. All of the generators we are talking about are of the synchronous kind, and although other asynchronous types are available (and sometimes the military use them for other reasons) machines in the 25kVA and up are normally fully synchronous types.


I agree with you BOD, there is no way that a 100HP diesel can produce 300HP even for a second or two, I can get that much given a bigger turbo and a lot more fuel injection (and black smoke) and.... but it is not there in the standard model. The overload characteristics are only the inertia and the rated power, and if the speed reduces for whatever reason the power may be as rated for a small change, but much and it goes very quickly. Engines for generators are very different in "tuning" to that in a car, the speed is expected to be constant at a particular value, and the fuel consumption is minimised at that speed to the loss anywhere else, particularly of torque at higher or lower speed. In the generator world, fuel consumption is everything, it is entirely driven by operating cost. A typical generator for film or television lighting is a peculiar beast, it may well have an external television sync input, and be crystal controlled for frequency to 3 decimal places for frequency (which might even be 48 or 50Hz, or 29.970*2 in the US). It is easy to think all generators are the same, they are not, and ones that can sync up and work in parallel are much more complex than one might expect.

Ah Mike, but I did specifically talk about synchronous machines! As it happens I do have a small generator of the asynchronous kind, but to be honest (and as I said) it is not very good at either constant frequency or constant voltage. All of the generators we are talking about are of the synchronous kind, and although other asynchronous types are available (and sometimes the military use them for other reasons) machines in the 25kVA and up are normally fully synchronous types.


I agree with you BOD, there is no way that a 100HP diesel can produce 300HP even for a second or two, I can get that much given a bigger turbo and a lot more fuel injection (and black smoke) and.... but it is not there in the standard model. The overload characteristics are only the inertia and the rated power, and if the speed reduces for whatever reason the power may be as rated for a small change, but much and it goes very quickly. Engines for generators are very different in "tuning" to that in a car, the speed is expected to be constant at a particular value, and the fuel consumption is minimised at that speed to the loss anywhere else, particularly of torque at higher or lower speed. In the generator world, fuel consumption is everything, it is entirely driven by operating cost. A typical generator for film or television lighting is a peculiar beast, it may well have an external television sync input, and be crystal controlled for frequency to 3 decimal places for frequency (which might even be 48 or 50Hz, or 29.970*2 in the US). It is easy to think all generators are the same, they are not, and ones that can sync up and work in parallel are much more complex than one might expect.