3000W Chinese Gensets Info.

I am still waiting to hear an explanation why MrWizard couldn't run his A/C with it. So much was said about this generator that it seems a mayor failure if it doesn't run a typical MH A/C unit. I do not see many people too worried about this finding. Maybe the Professor can report his findings after he finishes grading papers.

Actually, I am waiting for George (MrWizard) to report his findings. The man knows considerably more about electric motors than I do. He has spent a lifetime working with them and has acquired a vast knowledge base on their problems and performance standards.

Of course, that doesn't keep me from making a knee jerk observation as to what might be going on.......

I am not currently interpreting his problem to be with the Champion, even if other generators did start the air conditioner previously. The problem is most likely one of age and design of the air conditioner. As such, I would not jump to the conclusion that his unit is a typical MH A/C unit.

This is a common problem for electric motors used in RV air conditioners that predate the advent of the use of scroll or rotary compressors and what is often called "SST" (soft start technology)in the latter. Like me, as they age, electric motors can become more stubborn and reluctant to get moving. RV air conditioners built before '94 or '95 are in all probability in the previous class.

Any electric motor that is at rest will require a considerable kick in the seat of the pants to get it moving. This instaneous current demand is referred to as the "locked rotor" current. An electric motor that may draw 10 to 12 ampres at speed and under a "normal" load can easily require 60 amps of current for a brief period of time to get it moving. The critical part of this statement is: What's normal? For some motors, LRC is only a fractional part of a second. For others, it can be several seconds. This time differential will depend upon the design of the motor, what load may be connected to the motor at the time it is trying to start, and even the age of the motor - which can influence the condition of any starting capacitors, bearings, etc. that can alter LRC/Time constant. AC power differs from DC in respect to the available AC power not being constant. Eventhough we take AC and average the output and think of it as consistent, it is actually periodic. To overcome this problem, larger motors often use a capacitor to store a little AC power for a few alterations before feeding it to the motor. Some also have separate start and run windings to reduce the LRC.

George indicated that he was going to install a hard start kit on his MH air conditioner. Such a kit usually includes a new, larger capacitor to collect electrical energy from the power source, delay the delivery of the energy a few milliseconds, and then use the full force of the stored power to kick the motor really hard. The result is that the motor starts moving, does not overload the power source and everyone is happy.

The extra kick from a "hard start" add on kit is often all that is needed to get the system back to "normal".