Refrigerator current load

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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.


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Re: Refrigerator current load
On 1/12/2020 5:43 PM, Tom Del Rosso wrote:
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   Are sure that is not just a fan running without the compressor  
running? It has to be more when the compressor runs.

                                         Mikek

Re: Refrigerator current load
On Sunday, January 12, 2020 at 6:43:33 PM UTC-5, Tom Del Rosso wrote:
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That sounds about right. A refrigerator maintains a low temperature, but ta
kes a long time to pull the contents down from room temperature. The compre
ssor 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 h
eat.

Re: Refrigerator current load
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 pressuriz
ed 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 sol
ar powered camper made out of a box truck.  

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

There are drawbacks. I would bet real money that if you put a new and old f

ew 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 1
60 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 hour
s with the doors open. Then you get a worst case scenario value for its cur
rent drain.

Re: Refrigerator current load
Jeff Urban wrote:
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Thanks to all.  This is good, so I can put some other loads on the  
fridge outlet.




Re: Refrigerator current load

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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.


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Knowledge may be power, but communications is the key
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Re: Refrigerator current load
danny burstein wrote:
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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.




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

Greg

Re: Refrigerator current load
On Sun, 12 Jan 2020 18:43:28 -0500, "Tom Del Rosso"

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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     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Refrigerator current load
Jeff Liebermann wrote:
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Frigidaire FFHT1621TS1



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.




Re: Refrigerator current load
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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 drai


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 m
anager to allow connecting an ammeter to one of their new refrigerators. I  
did.

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