Circuit Man:Got a few questions to toss at you.
i have an old 1100 watt generator that has no circuit breakers,
It may be "Size Restricted" - meaning the Prime Mover (Gasoline Engine) can only produce enough Brake Horsepower to drive a load with 1100 Watts of True Power;
or the exciter may be "auto-regulated", so the Genny can only deliver 1100 Watts to a given load/load combination.
This would eliminate the need to protect the internal circuitry + receptacle from overcurrent issues, since there is no way to exceed their capacity by limiting the Genny's output power.
Very crude, yet effective technique, which keeps the manufacturing costs lower, + reduces maintenance issues
(also reduces the manufacturer's liability from fried wires emitting smoke + flames!)
when i overload it the motor runs like it is wide open with no load.
How are you overloading it?
If you are placing a bolted fault (solid short circuit) across the circuit, then the Prime Mover would attempt to run at full speed, trying to develop the highest Horsepower it may.
In that situation, the Governor will be run out to the extreme limits, and the Prime Mover should run at rated speed per the desired output frequency.
The Genny's windings will not fry, because the Prime Mover cannot develop any more Horsepower beyond this point.
After some time, the Genny's case will become warm, and the fuel should be consumed at the highest rate, since the Prime Mover is developing its rated Horsepower continuously.
This scenario would allow the full 1100 Watts to be driven into a load, with the Prime Mover's speed running steadily at top RPMs (according to the rated output frequency).
If what you are saying is the Prime Mover "Bogs down, then runs at a high speed" - which exceeds what would be normal for a governed frequency, then most likely the Exciter's field is automatically compensated (reduced) to limit the Genny's output.
Is the Generator's output AC or DC?
If you are intentionally overloading the Genny with an Electric Motor, here are a few questions:
- Is the Motor an AC Induction Motor?
- Is the Motor a Series-Wound Commutator Motor?
- Do you "load up" the Motor gradually, or start it with a large load?
- Is the Motor larger than 1/2 HP?
- Does the Electric Motor's speed reduce?
- What is the Voltage measured at the Motor / Genny output when loaded to capacity?
If you load up the Genny's output with Incandescent Lamps, do they dim down and stay dim when the Prime Mover's speed goes high?
Kind of sounds like an auto limit-compensated exciter.
If not, the Prime Mover is simply running at full speed and developing full HP.
when i take the load off & drop it to a smaller load it acts like it's supposed too.
Not sure what you mean here - do you remove the heavy load, then apply the smaller load instantly (with the Prime Mover running), or do you remove the large load, wait a few seconds, then apply the smaller load after the Prime Mover has re-governed its speed and output?
It could simply be that the Prime Mover is "tight", or the Generator is "tight" - or both, which results in a non-steady load applied to the Prime Mover when the "smaller load" is applied - causing it to "search' for a steady governor speed.
Some questions regarding the "small load" scenario:
Does the Generator / Prime Mover idle steadily at a low speed, when there is no load connected?
What type of load are you applying, when you connect the "small load"?
What is the overall reaction of the Prime Mover's speed (does it try to catch up to speed constantly, or just lag).
Does this behavior occur when applying various types of "small loads" across the circuit?
Is the smaller load below 1000 Watts?
Is it below 500 Watts?
Is it an Inductive load or Resistive load?
What is the Voltage at the load during this period of time?
it has not burnt out the windings. all is ok. what causes this?
Most likely, the windings will not lose smoke or flames, because the Prime Mover (the Gasoline Engine driving the Electric Generator) is limited to a certain Horsepower, and it can only transduce that level of Horsepower to the Generator.
Simply stated, the Prime Mover can only develop an equivalent Horsepower to the 1100 Watts rating of the Generator, so therefore the Prime Mover develops 1100 Watts and no more - after that point, it would stall.
The Exciter (Electromagnetic Field Windings, or "Rotor") which creates the Mag Field needed for Inducing the Stator windings, may be "Limiting" the output by dropping the Field strength to near nothing, if the output becomes excessive.
This would cause the Prime Mover to run in an "Unloaded State", as there is very little work being done at this time.
Please provide additional information, as I would like to help you understand what is going on with this Generator - and consequentially, explain other Generators too!
Scott