Just had my own experience and problem with one of those cheap ChiCom 2 stroke generators.

[Daniel Who Wants to Know]

I am helping do an engine swap on a 91 Caravan and we are using the
generator to power lights. The problem seems to be that the gen really
doesn't like inductive loads as it ran the fluorescent lights or a metal
halide light separately but not both together. With both on the voltage
drops and the lights just flash on and off while the engine just loafs with
no signs of being bogged down at all. I need to know if I can use some of
the motor run capacitors I have laying around to power factor correct the
lights and make them all work at the same time. The total load should be
about half of the 750 watts continuous that this one claims to supply. As a
test I plugged in a small toaster oven and the engine bogged right down so I
know the gen is capable of supplying good power.

 

[Daniel Who Wants to Know]

Your symptoms are consistent with having more inductive load than the
alternator can handle. Inductive loads do not load the engine but can
cause the voltage to drop excessively. I would think the capacitors would
permit the system to work okay. Just try the smallest capacitor first,
preferably connected at the same time as the other loads, and increase if
necessary. Too much capacitance can raise the voltage too much and ideally
you would want the capacitor current to nearly equal the inductive part of
the load current.

Don Young

Although I was not at the location where the inductive lights are I tried
plugging in a 500 watt halogen light and then plugged in a 25 microfarad
capacitor and the halogen did get brighter. The no load voltage on the
gen's built in meter is about 100v although it bounces around as the
governor hunts. With the 25uF connected it raises to 120v and with 35
connected (25+10 dual run cap) it goes to about 150v. I ordered my first
Kill-A-Watt off of Ebay and it should be here today or in a few days
(shipped the 22nd) so hopefully I can use it to get the power factor as
close to 1 as possible and check the frequency and volts at the same time.
Thanks

 

[Daniel Who Wants to Know]

A halogen light has a unity power factor so your cap isn't correcting any
PF problem
What it IS doing is affecting the field excitation and therefore the
voltage
regulation point. You can do the same thing by adding capacitance to the
aux
excitation winding that already connects to a capacitor.

These harmonically excited generators don't like low power factors,
lagging or
leading (what you're doing when you add capacitance to a unity PF load).
You'll need
to adjust the PF for the running load with the mercury light attached.
The problem
is, the PF of the light changes radically as the light warms up, assuming
you have a
regular PF light. The PF is lowest upon ignition. In fact, the VA draw
remains
similar from ignition through full output.

High PF lights almost always have a capacitor in series with the lamp.
You might
give that a try if paralleling the cap across the input doesn't work well
enough.

I do have to say that I've had more trouble trying to get mercury/HID
lights to run
on small generators and inverters than just about anything else I've
messed with. A
400 watt merc light will extinguish itself after it is almost fully on
even on a 1500
watt inverter. The same light works fine on this same generator we're
talking about
but the generator won't pull very much of any other load. I suspect that
the low PF
is affecting it but I haven't measured it yet.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
In theory, there is no difference between theory and practice. In
practice, there is.

Got my KAW yesterday and the capacitors did work quite well on the
generator. We ended up not using the metal halide (I think) light as once
the voltage was proper the fluorescent lights were bright enough for the top
stuff with an LED flashlight on hand for those dark spots underneath. We ran
an angle grinder with a cutoff wheel to grind through the exhaust flange
bolts and the gen ran it fine with the lights just dimming for a sec from
the turn on surge. It was interesting to hear the engine note change with
changes in load from grinding through those bolts. The final voltage,
frequency, and watts without the grinder on ended up being 140V, 64Hz, and
230W per the KAW as I ran the voltage on the high side because it was below
freezing in the garage and the fluorescent shop lights don't have cold
weather ballasts in them as at the normal 120 from either the grid power
before the house burned down or on the gen they flickered and wouldn't fully
light up. I am wondering why the frequency was so high though as I didn't
touch the governor but did note that it has a row of holes for the spring so
it may be adjustable.

I must say that I don't remember anyone on here saying that the KAW beeps
when the buttons are pressed but it does. It reported 76 watts @ 122V for a
75 watt 120V incandescent bulb in a clamp lamp on grid power and 0 watts and
195VA with just a 35uF capacitor plugged in. so it seems fairly accurate and
works properly. Does anyone know what it will read with reverse power flow
through it such as supplying power instead of consuming it like a grid tie
inverter does? I may have to make a male-male and a female-female cord to
find out.

 

[Daniel Who Wants to Know]

I am helping do an engine swap on a 91 Caravan and we are using the
generator to power lights. The problem seems to be that the gen really
doesn't like inductive loads as it ran the fluorescent lights or a metal
halide light separately but not both together. With both on the voltage
drops and the lights just flash on and off while the engine just loafs
with
no signs of being bogged down at all. I need to know if I can use some of
the motor run capacitors I have laying around to power factor correct the
lights and make them all work at the same time. The total load should be
about half of the 750 watts continuous that this one claims to supply. As
a
test I plugged in a small toaster oven and the engine bogged right down so
I
know the gen is capable of supplying good power.

Sorry, the whole thing makes no sense to me. Most electrical
appliances were designed for cheap and abundant electricity. An
automobile engine is one of the least efficient ways possible to
generate electricity. Efficient LED or fluorescent lighting, and a few
electronics are the only few things that have to be powered by
electricity. Nearly everything else can be done with gas, wood or
manually. All that's required is to lose the "switch-on convenience"
mentality.

We aren't talking about using the vehicle engine to produce electricity we
were talking about using a cheap small 2 horsepower 2 stroke-cycle 750/850
watt generator to power lights to be able to see to do an engine swap on the
Caravan. Grid power is unavailable as the house that the garage was wired
to for power burnt down to the ground.

 

[Daniel Who Wants to Know]

On Tue, 26 Feb 2008 20:37:01 GMT, "Daniel Who Wants to Know"


A typical small generator frequency spec is 58-62 hz. That is, the
governor is set
up for 62 hz no-load. The engine speed sags to 58 hz at full load. This
is for
4-stroke engines with good tight governors.

The speed variation on the 2-stroke engine is larger so I'm not surprised
to see that
high a light-load frequency. What you want to see is for the frequency to
be about
60 hz at about half load and to vary either side of half load. Don't
expect too much
from that little generator, specifically the governor.


I've never run a KAW in reverse. Be interested to see how it performs.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Unable to locate Coffee -- Operator Halted!

I just tried the reverse thing via a male-male cord I made and a power strip
with the KAW and the load both plugged in to it with its switch off and its
cord unplugged from the wall and hanging loose and the KAW operated
normally. I was expecting at least a negative symbol or it to just not read
watts at all but it acts exactly the same as it does with forward power.

 

[Daniel Who Wants to Know]

Hmm, interesting. Did the PF read correctly too?

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Remember, amateurs made the Ark, professionals made the Titanic.

Yep just double checked to be sure and it showed ~.6 PF 130W both forward
and backward for a Compaq computer with a 2.93GHz Celeron and a 17" CRT
monitor sitting idle on the Mandriva Linux 2007 spring desktop.