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Xantec inverter voltage Low?

R

Rob

Jan 1, 1970
0
Hi all, bought a Xantec "X Power" 1750W inverter. Measured the voltage
and
got 103.5 (no load). Thinking there was something wrong, I exchanged it
for another. The voltage on the new one is 104.9, when I loaded it the
volts went up to 109.7 (within the +/-5% noted in the manual). Is this
normal? Don't want to burn out our fridge.

Also as a note I tried to run a full size fridge (25+) years old. It
pegged the meter, on the inverter starting and ran at 2 'bars',
but did start and ran the fridge (its a spare we don't use). Tried it
on the one we use (4+) years old and the meter went about 1/3 up when
starting then didn't light up even one 'bar' when running. Big
advancement on efficiency in 20 years eh?

Rob
 
W

William Mcfadden

Jan 1, 1970
0
Hi all, bought a Xantec "X Power" 1750W inverter. Measured the voltage and
got 103.5 (no load). Thinking there was something wrong, I exchanged it for
another. The voltage on the new one is 104.9, when I loaded it the volts
went up to 109.7 (within the +/-5% noted in the manual). Is this normal?

It could be the meter. Most AV voltmeters are designed to measure
sinewaves. "Modified sinewave" inverters (i.e., most inverters on the
market today) put out a non-sinusoidal waveform and require a "true RMS"
meter to measure the voltage correctly.

"Pure sinewave" inverters can be measured with either kind of meter.
 
R

Rob

Jan 1, 1970
0
Its an older digital meter, but you have a point about the modified wave. The
reason I questioned the voltage is when I finished running the fridge off the
inverter, I plugged it back into our local nuke plant and it ran better(?), the
fan picked up a bit, just sounded better running off the wall plug. I'm
concerned about doing damage to the fridge. I understand some things do not do
well off inverters, do you know if a full size fridge is one of them?....Rob
 
S

Scott Willing

Jan 1, 1970
0
Hi all, bought a Xantec "X Power" 1750W inverter. Measured the voltage
and
got 103.5 (no load). Thinking there was something wrong, I exchanged it
for another. The voltage on the new one is 104.9, when I loaded it the
volts went up to 109.7 (within the +/-5% noted in the manual). Is this
normal? Don't want to burn out our fridge.

Presuming this is a "modified sine wave" (a.k.a modified square wave)
inverter, and that your meter is not true RMS reading, you're probably
fine. The peak of a modified sine/square waveform is around 150V, and
the meter reads 0.7x peak, which would be... yep, around 106V.

Keep an eye on the temperature of the motor running off that inverter.

-=s
 
R

Roger_Nickel

Jan 1, 1970
0
Rob said:
Its an older digital meter, but you have a point about the modified wave. The
reason I questioned the voltage is when I finished running the fridge off the
inverter, I plugged it back into our local nuke plant and it ran better(?), the
fan picked up a bit, just sounded better running off the wall plug. I'm
concerned about doing damage to the fridge. I understand some things do not do
well off inverters, do you know if a full size fridge is one of them?....Rob
the output of a modified sinewave inverter has a higher harmonic content
than ordinary mains power. When feed into an electric motor these
harmonics create rotating magnetic feild components in the rotor which
cannot be followed by the rotor. The motor will run noisier and hotter
than it would on mains power. Most modified sinewave inverters have
around 3% of the output power in the harmonics, and this is dissipated
as heat in the motor. Modern motors can be around 90% efficient so this
could represent a 30% increase in dissipation.
 
J

Jeremy Moberg

Jan 1, 1970
0
Rob said:
Hi all, bought a Xantec "X Power" 1750W inverter. Measured the voltage
and
got 103.5 (no load). Thinking there was something wrong, I exchanged it
for another. The voltage on the new one is 104.9, when I loaded it the
volts went up to 109.7 (within the +/-5% noted in the manual). Is this
normal? Don't want to burn out our fridge.

Also as a note I tried to run a full size fridge (25+) years old. It
pegged the meter, on the inverter starting and ran at 2 'bars',
but did start and ran the fridge (its a spare we don't use). Tried it
on the one we use (4+) years old and the meter went about 1/3 up when
starting then didn't light up even one 'bar' when running. Big
advancement on efficiency in 20 years eh?

Rob

Rob,

Do you have a long undersized wire run between the inverter and the plug in
you are testing, you could lose voltage that way. Check all the connections
also.

Jeremy
 
P

ptaylor

Jan 1, 1970
0
Jeremy said:
Rob,

Do you have a long undersized wire run between the inverter and the plug in
you are testing, you could lose voltage that way. Check all the connections
also.

Jeremy
I had a similar problem with a smaller 300W inverter.You may need to
use heavier wire from the batt(s) to the inverter.Also,try to keep the
wire run short.This solved my problem,I had 2 feet of 12awg wire,and
went to about 8 inches of 10awg,with the inverter strapped to the side
of the 17AH battery (for portable power.)No probems since.
 
R

Rob

Jan 1, 1970
0
Jeremy, thanks for the reply, I'm using about 10 inches of #4awg. I've since made
up 2 more (so I'll have 2 X #4 on each terminal), also I'm going to pick up a good
thick extension cord just for the fridge.....then cross my fingers next power
outage, and hope the fridge survives.
 
R

Rob

Jan 1, 1970
0
Roger, thanks for the reply, I admit I'll have to ponder it to fully understand it,
but from first impression, it the best I'm gonna get from a modified sine wave
inverter. I assume it should cause no immediate harm to the fridge. (Perhaps shorten
the total life of the appliance). And it is only for the times our power is off as
happened here for 3 days last summer. Perhaps one day a nice Honda
generator...........thanks again for the info... Rob
 
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