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Refrigerator current load

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Tom Del Rosso
Guest

Mon Jan 13, 2020 1:43 am   



I expect a large fridge to draw around 5 amps, but my clamp transformer
(on one wire of a broken-out extension cord of course) and Fluke
together say 830ma when the thing is running. Does that seem wrong? It
measures the toaster oven at 9.1A and the fridge light at 300ma.


--

amdx
Guest

Mon Jan 13, 2020 2:04 am   



On 1/12/2020 5:43 PM, Tom Del Rosso wrote:
Quote:
I expect a large fridge to draw around 5 amps, but my clamp transformer
(on one wire of a broken-out extension cord of course) and Fluke
together say 830ma when the thing is running. Does that seem wrong? It
measures the toaster oven at 9.1A and the fridge light at 300ma.


Are sure that is not just a fan running without the compressor
running? It has to be more when the compressor runs.

Mikek

Michael Terrell
Guest

Mon Jan 13, 2020 2:05 am   



On Sunday, January 12, 2020 at 6:43:33 PM UTC-5, Tom Del Rosso wrote:
Quote:
I expect a large fridge to draw around 5 amps, but my clamp transformer
(on one wire of a broken-out extension cord of course) and Fluke
together say 830ma when the thing is running. Does that seem wrong? It
measures the toaster oven at 9.1A and the fridge light at 300ma.


That sounds about right. A refrigerator maintains a low temperature, but takes a long time to pull the contents down from room temperature. The compressor is tiny, inside the housing It is spring mounted to reduce the noise, and to surround the motor with refrigerant. If it drew 9.1A, that would be over a Kilowatt that would need to be dissipated, along with the interior heat.

Jeff Urban
Guest

Mon Jan 13, 2020 2:41 am   



We measured a new fridge at the store, had to talk the manager into it but I built a box with a cord and outlet and a wire looped outside for a clamp on ammeter.

We got a peak of like 9 amps or so to start but then it went be;ow one amp.

However if the thing has not been in service the condenser is not pressurized which does make the compressor draw more. We didn't want to hang around all day so we took the data and went on to other things. This was for a solar powered camper made out of a box truck.

The trend now is for a smaller refrigeration system that runs longer. The peak at startup is one issue but there are so many others. Manufacturing costs, weight/freight. It all needs to be considered when you make decisions like that in design.

There are drawbacks. I would bet real money that if you put a new and old fridge out on 100º in the sun the old one could cool the food but the new one would not. But how many people are going to do that ?

So you might have 80 watts for 6 hours but with an old one you would have 160 watts for 3 hours. The lower drain means less loss of power in the house wiring, and not contributing as much to peak demand.

Thing is, after the startup surge, take and run the thing for a couple hours with the doors open. Then you get a worst case scenario value for its current drain.

Tom Del Rosso
Guest

Mon Jan 13, 2020 4:04 am   



Jeff Urban wrote:
Quote:
We measured a new fridge at the store, had to talk the manager into
it but I built a box with a cord and outlet and a wire looped outside
for a clamp on ammeter.

We got a peak of like 9 amps or so to start but then it went be;ow
one amp.


Thanks to all. This is good, so I can put some other loads on the
fridge outlet.

danny burstein
Guest

Mon Jan 13, 2020 4:58 am   



In <qvgjbq$5l5$1_at_dont-email.me> "Tom Del Rosso" <fizzbintuesday_at_that-google-mail-domain.com> writes:

Quote:
Jeff Urban wrote:
We measured a new fridge at the store, had to talk the manager into
it but I built a box with a cord and outlet and a wire looped outside
for a clamp on ammeter.

We got a peak of like 9 amps or so to start but then it went be;ow
one amp.

Thanks to all. This is good, so I can put some other loads on the
fridge outlet.


Maybe, maybe not.

While typical refrigerators these days pull one amp (or less...)
while running, the "frost free" ones use a hell of a lot
more during the defrost cycle.

I've measured _500_ watts (4 amps) on mine.

A meeting hall I work with had a problem where the
circuit breaker feeding the overhead lights would
overload and open up, plunging the room into darkness.

Which made no sense. Yes, I re-measured the load and
swapped breakers...

On checking further, I found that they had added
an outlet which was slaved off the lighting circuit [a]
and was being used for a refrigerator.

It took some head scratching before I realized that
when the lights were on at the same time the refrigerator
went into defrost mode, the power draw exceeded the
breaker rating.

Since the place was rarely used, just about all the
time the defroster kicked in the lights were off,
so these blackouts were few and far between...

[a] installed by a professional and licensed electrician
who should have known that Code does NOT like appliance
outlets on lighting circuits for exactly this reason.


--
_____________________________________________________
Knowledge may be power, but communications is the key
dannyb_at_panix.com
[to foil spammers, my address has been double rot-13 encoded]

Jeff Liebermann
Guest

Mon Jan 13, 2020 6:30 am   



On Sun, 12 Jan 2020 18:43:28 -0500, "Tom Del Rosso"
<fizzbintuesday_at_that-google-mail-domain.com> wrote:

Quote:
I expect a large fridge to draw around 5 amps, but my clamp transformer
(on one wire of a broken-out extension cord of course) and Fluke
together say 830ma when the thing is running. Does that seem wrong? It
measures the toaster oven at 9.1A and the fridge light at 300ma.


Make and model of the fridge? 117VAC or 240VAC? I can possibly
lookup the expected current drain online and do a sanity check. I
found a few charts that claim a full size refrigerator/freezer should
draw about 700 watts. 5A sounds about right:
117VAC * 5A = 585 VA
No clue on the PF (power factor) so I'll use VA instead of watts.

If you're seeing only 0.83A, then you're looking at the current drawn
by a fan or light bulb in the fridge, not the compressor. Try
lowering the temperature setting of the thermostat temporarily to
force the compressor to start.

--
Jeff Liebermann jeffl_at_cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Tom Del Rosso
Guest

Mon Jan 13, 2020 6:47 am   



Jeff Liebermann wrote:
Quote:
On Sun, 12 Jan 2020 18:43:28 -0500, "Tom Del Rosso"
fizzbintuesday_at_that-google-mail-domain.com> wrote:

I expect a large fridge to draw around 5 amps, but my clamp
transformer (on one wire of a broken-out extension cord of course)
and Fluke together say 830ma when the thing is running. Does that
seem wrong? It measures the toaster oven at 9.1A and the fridge
light at 300ma.

Make and model of the fridge? 117VAC or 240VAC? I can possibly
lookup the expected current drain online and do a sanity check. I
found a few charts that claim a full size refrigerator/freezer should
draw about 700 watts. 5A sounds about right:


Frigidaire FFHT1621TS1


Quote:
117VAC * 5A = 585 VA
No clue on the PF (power factor) so I'll use VA instead of watts.

If you're seeing only 0.83A, then you're looking at the current drawn
by a fan or light bulb in the fridge, not the compressor. Try
lowering the temperature setting of the thermostat temporarily to
force the compressor to start.


Tthat 800ma is when it's making noise. It's less than 10ma the rest of
the time. The other loads are toaster and microwave so they draw zero
most of the time.

The most unfortunate thing is that all the outlets in the kitchen seem
to be on one breaker. I say so because there is a 3 volt drop on any
outlet when the toaster oven draws 9 amps. In another room it drops
100mv or less.

Tom Del Rosso
Guest

Mon Jan 13, 2020 7:02 am   



danny burstein wrote:
Quote:
In <qvgjbq$5l5$1_at_dont-email.me> "Tom Del Rosso"
fizzbintuesday_at_that-google-mail-domain.com> writes:

Jeff Urban wrote:
We measured a new fridge at the store, had to talk the manager into
it but I built a box with a cord and outlet and a wire looped
outside for a clamp on ammeter.

We got a peak of like 9 amps or so to start but then it went be;ow
one amp.

Thanks to all. This is good, so I can put some other loads on the
fridge outlet.

Maybe, maybe not.

While typical refrigerators these days pull one amp (or less...)
while running, the "frost free" ones use a hell of a lot
more during the defrost cycle.

I've measured _500_ watts (4 amps) on mine.


That might be a few times a day but my other loads are used even less
often. The total is still under 15 amps which is what motivated me to
measure it.

gregz
Guest

Mon Jan 13, 2020 9:29 am   



"Tom Del Rosso" <fizzbintuesday_at_that-google-mail-domain.com> wrote:
Quote:
Jeff Urban wrote:
We measured a new fridge at the store, had to talk the manager into
it but I built a box with a cord and outlet and a wire looped outside
for a clamp on ammeter.

We got a peak of like 9 amps or so to start but then it went be;ow
one amp.

Thanks to all. This is good, so I can put some other loads on the
fridge outlet.


Newer ones seem to draw less on auto defrost. I think some older ones may
draw a bunch, like 10 amps or more.

Greg

Jeff Urban
Guest

Mon Jan 13, 2020 10:16 am   



>If you're seeing only 0.83A, then you're looking at the current >drawn by a fan or light bulb in the fridge, not the compressor.

No, I am sure of what I said, that was considered at the time.

But if the compressor is not pumping into a loaded condenser the power drain will be low as I stated. Your fans n shit are more like ¼ amp.

Go look, you'll see I am right. It just so happens I have recent experience with this. Not many people last year went into a store and convinced the manager to allow connecting an ammeter to one of their new refrigerators. I did.

David Lesher
Guest

Mon Feb 24, 2020 5:45 am   



Besides the NEC violation, the other reason not to share the
fridge circuit is when/if the toaster/mixer/whatever trips it,
and you do not notice, you get was-frozen food.
--
A host is a host from coast to coast.................wb8foz_at_nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

pfjw@aol.com
Guest

Mon Feb 24, 2020 3:45 pm   



In general, the best means of deciding how much current a device takes is a peak-holding watt/hour meter. Various devices may be purchased at your local Big-Box, Amazon and any number of other outlets.\

Such devices are also good for discovering real or pending problems with appliances and any number of other items around the house.

Why speculate when good data is readily available?

Peter Wieck
Melrose Park, PA

Fox's Mercantile
Guest

Mon Feb 24, 2020 4:45 pm   



On 2/24/20 8:38 AM, pfjw_at_aol.com wrote:
> Why speculate when good data is readily available?

Because this is Usenet.
The standard rules of engagement are to take something simple,
blow it all out of proportion, then continue to beat it like
a dead horse with wild speculation.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

amdx
Guest

Mon Feb 24, 2020 5:45 pm   



On 1/12/2020 10:47 PM, Tom Del Rosso wrote:
Quote:
Jeff Liebermann wrote:
On Sun, 12 Jan 2020 18:43:28 -0500, "Tom Del Rosso"
fizzbintuesday_at_that-google-mail-domain.com> wrote:

I expect a large fridge to draw around 5 amps, but my clamp
transformer (on one wire of a broken-out extension cord of course)
and Fluke together say 830ma when the thing is running. Does that
seem wrong? It measures the toaster oven at 9.1A and the fridge
light at 300ma.

Make and model of the fridge? 117VAC or 240VAC? I can possibly
lookup the expected current drain online and do a sanity check. I
found a few charts that claim a full size refrigerator/freezer should
draw about 700 watts. 5A sounds about right:

Frigidaire FFHT1621TS1


117VAC * 5A = 585 VA
No clue on the PF (power factor) so I'll use VA instead of watts.

If you're seeing only 0.83A, then you're looking at the current drawn
by a fan or light bulb in the fridge, not the compressor. Try
lowering the temperature setting of the thermostat temporarily to
force the compressor to start.

Tthat 800ma is when it's making noise. It's less than 10ma the rest of
the time. The other loads are toaster and microwave so they draw zero
most of the time.

The most unfortunate thing is that all the outlets in the kitchen seem
to be on one breaker. I say so because there is a 3 volt drop on any
outlet when the toaster oven draws 9 amps. In another room it drops
100mv or less.



I'd have a little concern about that 3v drop. It could be just a long
run of wire, (I doubt it) or a poor connection somewhere between,
starting at the box and going to the outlet.
Warning I once connected several freezers to an outlet, in an outdoor
porch. It was fine for years and then one day a got a burning smell.
Tried and tried to sniff it out, but it went a way. A couple days later
I smelled it again. I traced behind a TV, I grabbed the TV plug and it
was very hot. I moved everything out, removed a panel from the wall.
Upon inspection the the outlet crumbled to pieces. The wire from the
Circuit breaker box terminated at the outlet, then another wire was
connected to the box that went to the outdoor outlet. A poor connection
to the box, heated up every time the freezers ran. I was lucky it didn't
start a fire. I installed 220v to a sub box and divided that for my
freezers after that.

Mikek

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