Author Topic: gen won't pow'r deep freeze (Read 3196 times)

Cornbelt · « **on:** April 21, 2011, 08:40:24 AM »

Anyone have any idea why my 9 KW generator won't run my deep freeze?
The sides get warm while the top gets cooler which means stuff is starting to melt.
Works just fine when the power comes back on.
Does it need a stronger capacitor maybe?

Cornbelt · « **Reply #1 on:** April 21, 2011, 08:42:50 AM »

(forgot to check the box for replies)

charles p · « **Reply #2 on:** April 21, 2011, 12:45:06 PM »

After Hurrican Isabel hit our island, a friend in the seafood business borrowed a generator to power his walk in freezer. It worked great until we turned the generator off to refuel it. The compressor would not start again. Someone got a booster to wire into the circuit and it started the compressor. When it went down the second time for fuel. it would not restart with that booster, so a second boostet was located and it started the compressor. Pretty soon his landlord let him connect to his 6-71 Diesel, and that did the job.

It takes more amps to start a freezer than to run it continuously. I'm not an electrician, just sharing my experience. I have run a 21 ft upright freezer for days on a generator half the size of yours, but I don't know what power consumption yours would require. Seems that you ought to have enough power for a home model.

Cornbelt · « **Reply #3 on:** April 21, 2011, 04:16:38 PM »

Its old enough it may need another or better capacitor anyhow (or be replaced completely). Too bad the compressor isn't exposed. The quick fix on the farm for a motor that wouldn't start was to whack it with a rubber hammer. If it went on then, it needed a capacitor.
This unit is 28 or 30 yrs old. The test for a new one will be whether or not it will work w/the generator.
Couldn't even find dry ice, and no one wants to sell just a qt. of liquid nitrogen.

PowPow · « **Reply #4 on:** April 21, 2011, 04:41:24 PM »

Most residential freezers are about 1/4 hp. Same as a refrigerator, better insulation, runs longer.

Could be the capacitor.

Could be a problem with the voltage drop in the line from the generator to the freezer. If there is a long run of small wire (#14 maybe) or some other stuff is on the circuit, when it tries to crank up the voltage drops over the line (maybe the lights go brown). The compressor trips on it internal overloads, then take a long time to cool off and auto reset. A shorter run or bigger wire solves that problem. Try going direct from freezer to gen with fat extension cord.

Could be low voltage coming out of the generator. Any other motors having a hard time starting? frig? window ac?

Could be you're not holding your mouth right. Don't know what that means but its my mother's explanation for why stuff won't work.

Cornbelt · « **Reply #5 on:** April 21, 2011, 04:54:10 PM »

Short #10 cable goes directly into the box. Also tried the freezer just by itself.
As far as A.C. goes, I havent tried that yet a-tall and hoping I won't need to, but I may just try it before I need it.
Air comp would hardly turn at all. It has a 5-7 hp 240v motor, so that one's not gonna be on the list of things I can use.

And by the way (strictly a hypothetical question): Could a guy use one of these for fishing?

PowPow · « **Reply #6 on:** April 21, 2011, 05:05:31 PM »

buy or borrow a $10 volt meter and check the output of the gen.
If its good, go buy a freezer capacitor, just like the one you had. might be $15.

I think the generator you use for fishing is a DC generator from an old telephone.

Cornbelt · « **Reply #7 on:** April 21, 2011, 05:33:25 PM »

Thanks, I'll try it.

Game wardens have a powered generator they use to get a fish count in order to know what to stock, but I havent seen one used. Maybe a telephone/weedeater combo.

FourBee · « **Reply #8 on:** April 21, 2011, 05:46:47 PM »

Quote from: Cornbelt on April 21, 2011, 08:40:24 AM

Anyone have any idea why my 9 KW generator won't run my deep freeze?
The sides get warm while the top gets cooler which means stuff is starting to melt.
Works just fine when the power comes back on.
Does it need a stronger capacitor maybe?

It doesn't sound like the freezer is at fault. A 9KW ought to run more than two freezers , plus several lights at one time .

blind ear · « **Reply #9 on:** April 21, 2011, 06:48:32 PM »

Do ou have a curcuit breaker that cuts off the back feed to the main service supply? Pulling the meter doesn't do it. ear

PowPow · « **Reply #10 on:** April 22, 2011, 12:14:33 AM »

Quote from: blind ear on April 21, 2011, 06:48:32 PM

Do ou have a curcuit breaker that cuts off the back feed to the main service supply? Pulling the meter doesn't do it. ear

are you talking about a transfer switch, that switches from power company to generator, either manually or automatically?
good question; without one, you could be trying to light up the world and some power co lineman.

hillbill · « **Reply #11 on:** April 22, 2011, 02:13:51 AM »

i run my deep freeze with a 6.5 kw generator easy. im thinking your gen may not be putting out what its supposed to.however ive had the same prob that you did with a 5hp air compressor and it was just 110 v.there is something about those newer small high output motors that takes a lot of juice to start them.

Glanceblamm · « **Reply #12 on:** April 22, 2011, 05:34:33 AM »

Quote from: PowPow on April 22, 2011, 12:14:33 AM

Quote from: blind ear on April 21, 2011, 06:48:32 PM
Do ou have a curcuit breaker that cuts off the back feed to the main service supply? Pulling the meter doesn't do it. ear

are you talking about a transfer switch, that switches from power company to generator, either manually or automatically?
good question; without one, you could be trying to light up the world and some power co lineman.

A manual or automatic disconnect goes without question and mainly because you would get one He$$ of a bang inside the house at the breaker box if the main came back on and Phases were crossed. Probably wouldnt do the transformer any good either. We had several cases of this in a ten day power outage due to an ice storm back in 78'. The affected breaker boxes were mainly turned into a pile of charcoal.

Interesting thought on lighting up the World with your generator. A transformer does not have any moving parts like a motor does so what the do is to use the appropriate windings on the intake and discharge side and rely on the field of the windings to produce power. This is called the "turn ratio" which would be incorrect to back feed to the main line. This point is moot though compared to crossing Phases.

I did get to run my generator for the first time at this residence on Wed night. 5500 w ran the Refrigerator & deep freeze along with a few light with no problem. I would also check the voltage output on yours as the portable generator is suppose to be ran under load once a month to keep it in working order on the output. In reality, I only average running the thing bout every three months and use a industrial heat gun for the load.

blind ear · « **Reply #13 on:** April 22, 2011, 05:52:13 AM »

I learned the hard way. Thank goodness our local power grid checks all residences before reheating a line. It scared me and I leave all power concernes to professioonals now. ear

PowPow · « **Reply #14 on:** April 22, 2011, 09:21:48 AM »

Quote from: Glanceblamm on April 22, 2011, 05:34:33 AM

...This is called the "turn ratio" which would be incorrect to back feed to the main line...

Wire-wound iron core transformers are bidirectional; if you backfeed 120/240 from a residential gen to the low side of a residential transformer, you will create a high voltage on the primary line, unless its gone to ground or the transformer fuse is blown.
The lineman should be and probably are checking generators for their own saftey prior to making repairs. I've heard that around here if you are the one backfeeding, they physically isolate your service (pull the meter, disconnect the service cable) and your power is "eventually" restored.

SHOOTALL · « **Reply #15 on:** April 22, 2011, 09:34:20 AM »

Is the generator set to idle ? Some generators won't rev up unless you have a good load. Lights for example can cause a gen to either not rev up or hunt when it does. Some generators have a time out feature that waits a few seconds to a few min. before starting. If you plug in the freezer along with a drill motor and start the drill in most cases a low load appliance will start and run. In some cases if you leave the drill running it will regulate the system and not hunt.

charles p · « **Reply #16 on:** April 22, 2011, 11:47:39 AM »

I have a manual disconnect that prevent me from charging my house from the generator pigtail without seperating me from the grid.

Question: If a 7kw generator were backfeeding onto the grid, would the load be so great that if would quickly stall the engine or damage the generator? I have no idea?

PowPow · « **Reply #17 on:** April 22, 2011, 11:57:37 AM »

Quote from: charles p on April 22, 2011, 11:47:39 AM

I have a manual disconnect that prevent me from charging my house from the generator pigtail without seperating me from the grid.

Question: If a 7kw generator were backfeeding onto the grid, would the load be so great that if would quickly stall the engine or damage the generator? I have no idea?

I have a manual switch too. I don't want to be the one to try it.
My guess is is would trip the generator's internal circuit breakers.
Mine is a 5 kW; if it hits 20 amps for a certain period of time, it trips.

hillbill · « **Reply #18 on:** April 22, 2011, 02:34:07 PM »

if your gen is backfeeding into the line and there is enuf draw on it, as ther prob would be, it will kill the motor.or thats what mine does when i forget to trip the breaker on the elec water heater.always trip the main breaker on your pole or pull the meter if yu have a older type service.yu dont want to be shockin the guys who are fixin yu lines.

Cornbelt · « **Reply #19 on:** April 24, 2011, 02:55:27 PM »

The whole system is isolated from the grid before using the generator. In addition to that, I throw all the breakers and only use the minimum.
Carb is either set to "choke" or "run", so there is no reed switch as on a welder, for instance.
But when the water pump kicks on, its easy to tell the gen is under a load. Other than shop equipment, that's probably what pulls the most amps. Shop equipment just stays off. No range, furnace, dryer or hot water heater either.

blind ear · « **Reply #20 on:** April 24, 2011, 04:21:56 PM »

Does the engine not rev up when you hook up the freezer? If not, the load demand for the welder governor to kick in may be too high for the freezer to activate it and up the engine RPMs. Could burn your freezer motor and the governor will kick in about the time it burns.

Had a cotton picker set up as a generator on fish ponds. Rpm drop for the engine was 10% drop for governor to work. Turn on a 20 hp electric mptor and the engine would slow down then pick back up to operateing speed slowly. No governor activation. The motor speed was manually set to operateing speed to begin with and didn't require load to reach op speed, just recovery to op speed with load demand and engine RPM drop.

If you can manually set the welder to op speed do that rather than rely on the governor to raise rpms with load demand.

I am probably wrong after re reading your last post.

ear

Cornbelt · « **Reply #21 on:** April 25, 2011, 07:03:57 AM »

The welder is a thing of the past; just mentioned it to contrast the differences . It needed a bit of amp drain to kick in and if it didn't get enough I had to use the manuel switch.

The generator doesn't have one; just runs at the set RPM, but the sound changes when its under a load.
Haven't tested the output yet. Today I'm putting wheels on it -to make it a little more geriatric friendly. Funny how stuff seems to outgrow me.

The Hermit · « **Reply #22 on:** April 27, 2011, 05:11:07 PM »

I have a small generator at my big cabin that I connect directly to either my water pump or freezer as needed. During the last ice storm I was with out electric for 19 days. I switched to kerosen lamps and my wood cook stove, but didn't want to loose some of the meat in the freezer, so I canned it, and now don't have a freezer at all. I also made a pipe arrangement with a check valve to get water by hand from my well. I left the kitchen light switch on just so I would know when the power came back on. I noticed one night that the light had a slight glow to it, kinda eerie. Somebody must have been feeding a generator back into the line. The power company came around to every place looking for the "(unprintable word) idiot". He wasn't too hard to find because at night we could hear a generator running about a mile or so away. Some folks just have no common sense.

The Hermit

curteric · « **Reply #23 on:** April 28, 2011, 02:25:54 AM »

I have a Gen that I can hook up to the house. When the weather forecast indicates that we may have a power outage, I put a small light bulb, plugged into a outlet, in my garage window. My garage is a separate building and feed from the pole separately. When the power goes out I isolate the house from the grid and use the Gen set. I know when the power comes back, because the light in the garage comes on. The neighbor lady will see the light and either stop or call to tell me that the light in the garage is on. She can't stand that light on for no reason, and I don't tell her what is going on, I just say I'll take care of it. Some times, depending on the weather, it will be on for 3-4 days.

Gaz-52 · « **Reply #24 on:** April 28, 2011, 03:27:21 AM »

Hi, Is the generator output frequency the same as your "mains "power ? e.g. 50Hz or 60 Hz. Next thing to check is whether the generator is producing power at the rated frequency, this is dependent on the generator running at the correct Rpm. Check the info on the generator "name plate" . A 50 Hz . is usually 3,000Rpm, and I think for 60Hz 3,600 Rpm would be about right.
You would need a "multimeter " with a Frequency/ cycles per second range ,or a rev counter of some kind to check the correct speed of the generator. As a point of interest , what type of electrical appliances will run on the generator as it is now ? This may give me a clue to the problem, but I don't think it is the freezer going by what you have said so far.
Cheers
Gazz ,
( gerriatric sparkie )

Cornbelt · « **Reply #25 on:** April 28, 2011, 04:31:08 PM »

Its a 60 hz outfit, but didn't come with any meters like the old ones used to, so I'm only going by faith to assume its set at the right speed. I have a tach, but can't get to anyplace to check it; (mechanical tach), and my multimeters don't show hz.
I like your idea well enough to find someone with the right meter just to see where things stand. I'm starting to think nothing is "wrong" with the generator or the freezer, just that they don't like each other. So now I gotta play shrink and delve into their disfunctional relationship. It ought to at least be as interesting as the in-laws.

PowPow · « **Reply #26 on:** April 28, 2011, 05:38:24 PM »

Plug an old fashioned clock with hands into it and compare it to digital watch.
However many seconds it clicks off during a digital clock minute is the frequency.

I think mine has some kind of centrifugal or magnetic thing pushing against a spring to regulate speed. If it goes to fast the centrifugal or magnetic force slows it down. If it goes too slow the spring steps on the gas. They balance out at 60 hz

Gaz-52 · « **Reply #27 on:** April 29, 2011, 02:49:54 AM »

An electric clock (A.C. Not battery) uses a "synchronous motor " and should keep near perfect time when powered by a generator providing it is running at the right speed. Comparing it to a digital watch or similar over 10 minutes
any difference should be noticeable and the speed can be adjusted up or down till the clock and watch are in Sync with each other .
I take it that the gene. will operate other appliances . Will it start a power saw? Fridge / freezer motors are sensative to incorrect Voltage/ frequency and can be damaged if run for extended periods on it .
Give us any other details , there may be a clue to the problem, I just hate to think of an "old mate "not having any way to keep the beer cold. ;

Cornbelt · « **Reply #28 on:** May 02, 2011, 03:51:54 AM »

I do have a clock. And I know how to use one (almost as well as a hammer). I'll give it a try.

SHOOTALL · « **Reply #29 on:** May 02, 2011, 08:27:24 AM »

Quote from: charles p on April 22, 2011, 11:47:39 AM

I have a manual disconnect that prevent me from charging my house from the generator pigtail without seperating me from the grid.

Question: If a 7kw generator were backfeeding onto the grid, would the load be so great that if would quickly stall the engine or damage the generator? I have no idea?

I would worry more about a lineman working on the "non energized " line . The step down transformer works the other way