no-cap fridges

[David Lesher]

I'm helping a friend fix a fridge remotely. The compressor
tried but won't start.

I suggested he check continuity on the run and start windings, the
starting relay, and the starting cap. Ooops, it has none!

<http://sendspace.com/file/emdg1e>
<http://sendspace.com/file/ckpnaw>

It's been 20 years since I took Machines, but I got an A. [And the
fridge is not much younger...] But I don't recall any capacitor-less
single-phase AC motors with good starting torque.

What gives?


--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Jeff Liebermann]

On Sun, 27 Sep 2009 17:28:31 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

I'm helping a friend fix a fridge remotely.

Beware of friends bearing broken devices.

The compressor tried but won't start.

Are you getting a clicking sound (i.e. overcurrent shutoff) or a
grinding sound (loss of lube)? Did this happen just after he moved
the fridge (broke loose the crud at the bottom of the compressor)?

I suggested he check continuity on the run and start windings, the
starting relay, and the starting cap. Ooops, it has none!

http://sendspace.com/file/emdg1e

It certainly does have a relay. Look on the compressor schematic.
It's labeled "PTC Relay" on the schematic. Depending on the model,
you might get lucky and find that it's removable.

It's been 20 years since I took Machines, but I got an A.

You get an "F" for this posting. Asking a repair question without
supplying the manufactory and model number is a capital crime. Turn
in your deploma and slap yourself on the wrist with a wooden ruler.

Also, while there may be some electronics inside a fridge, methinks
that one of the appliance repair forums or newsgroups might be a more
appropriate place to ask your question.

[And the
fridge is not much younger...] But I don't recall any capacitor-less
single-phase AC motors with good starting torque.

What gives?

If it's 20 years old, it's quite possible that something in the
compressor has worn out. A freon leak will eventually cause the
compressor to lose lubrication and grind to a halt.

This might be helpful:
<http://www.applianceaid.com/refrigerator.html#clicking>


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

 

[Wild_Bill]

I'm not all that familiar with these motors, but they have been made without
starting capacitors for quite a long time. I don't remember how long it's
been since I've seen a household fridge with a starting cap, maybe in the
60s or 70s, and those would've been old models at the time.
Maybe exceptionally large household or commercial reefers still use starting
caps.

The relay and overload are the motor's control and protection devices.

One possible motor failure mode could be that the motor was in the run cycle
and a brief power disruption caused the motor to try to restart before the
relay had time to reset (these typically aren't electromagnetic relays lke
common ones with contacts actuated by a coil).
During these power-fail restarts, the winding can open if the overload
doesn't open the circuit in time.
I've seen these events happen a couple of times, and the unit just hummed
until the overload opened to protect the motor.

You're correct, in that many machine, utility or appliance motors do have
greater starting torque when fitted with a starting capacitor, but the
small, hermetically enclosed fridge motors in consumer fridges aren't the
same.

If the fault is within the motor enclosure or cooling/freon components, the
only practical option will probably be to replace the fridge.

--
Cheers,
WB
..............


"David Lesher" <wb8foz@panix.com> wrote in message
news:h9o7bv$kf4$1@reader1.panix.com...

I'm helping a friend fix a fridge remotely. The compressor
tried but won't start.

I suggested he check continuity on the run and start windings, the
starting relay, and the starting cap. Ooops, it has none!

http://sendspace.com/file/emdg1e
http://sendspace.com/file/ckpnaw

It's been 20 years since I took Machines, but I got an A. [And the
fridge is not much younger...] But I don't recall any capacitor-less
single-phase AC motors with good starting torque.

What gives?


--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Jeff Liebermann]

On Sun, 27 Sep 2009 23:36:35 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

Jeff Liebermann <jeffl@cruzio.com> writes:

The compressor tried but won't start.

Are you getting a clicking sound (i.e. overcurrent shutoff) or a
grinding sound (loss of lube)? Did this happen just after he moved
the fridge (broke loose the crud at the bottom of the compressor)?

It's cycling on overcurrent.

There's your clue. The motor is either grinding, not turning, stuck,
or fried (shorted winding). In all cases, the motor/compressor
assembly appears to dead. It's sealed, unrepairable, and probably a
good candidate for eWaste.

Been there for 10+ years.

Past performance is not a good indication for future results. Works
for stocks, investments, and refrigerators.

It's labeled "PTC Relay" on the schematic. Depending on the model,
you might get lucky and find that it's removable.

It is. But there's no cap.

I haven't bothered to check, but I don't recall seeing a starting
cazapitor in any of the assorted refrigerators I've owned or attempted
to repair in perhaps 20 years.

GE Hotpoint CTX18BACGRWW.
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=205542&diagram_id=21197026#d21197026

Thanks. The diagram shows that the relay is replaceable. However, I
doubt that's the problem. It might be that the overload sensor is
tripping too early. Tear the relay and overload assembly apart, clean
all the junk out, clean the contacts, and look for damage. You might
get lucky.

Read the following:
<http://www.applianceaid.com/refrigerator.html#clicking>
Note the photos of the various relay failures.

I'm not sure I want to suggest this because there's too many ways this
can go awry. Just be very careful. Take an insulated stick and jam
the relay closed so the compressor is running. MEASURE the AC current
or load with a AC wattmeter or clamp on ammeter. If it's sky high,
give up. If it seems in spec, listen to the compressor. If it sounds
like it's grinding, you're out of coolant. If it wobbles, you've
blown a bushing. If it purrs, it's ok and there's something wrong
with the relay or its the overload detector.

The people here are far smarter.....

Nope. Just mention something political and watch the average IQ drop
dramatically. Also, I sometimes get bored fixing computahs and
printahs. Next time, I'll play dumb.

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

 

[Meat Plow]

On Sun, 27 Sep 2009 17:28:31 +0000 (UTC), David Lesher
<wb8foz@panix.com>wrote:

I'm helping a friend fix a fridge remotely. The compressor
tried but won't start.

I suggested he check continuity on the run and start windings, the
starting relay, and the starting cap. Ooops, it has none!

http://sendspace.com/file/emdg1e
http://sendspace.com/file/ckpnaw

It's been 20 years since I took Machines, but I got an A. [And the
fridge is not much younger...] But I don't recall any capacitor-less
single-phase AC motors with good starting torque.

What gives?

The motor doesn't need a lot of torque when the high side bleeds down.
Until then it can cycle on the overload until the high side bleeds
down if cooling is called for.

Check the start relay and winding.

 

[Bob Larter]

David Lesher wrote:

Jeff Liebermann <jeffl@cruzio.com> writes:
[...]
Also, while there may be some electronics inside a fridge, methinks
that one of the appliance repair forums or newsgroups might be a more
appropriate place to ask your question.

The people here are far smarter.....

Here's a bloke who knows how to get people onside. ;^)

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Bob Larter]

Jeff Liebermann wrote:

On Sun, 27 Sep 2009 23:36:35 +0000 (UTC), David Lesher
The people here are far smarter.....

Nope. Just mention something political and watch the average IQ drop
dramatically.

Let's not go there...


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Mark Zenier]

Yea, I'm three weeks behind so shoot me.

In article <5s60c5lsb3cpkq99odg75rs42jg4vg3bhg@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

It's labeled "PTC Relay" on the schematic. Depending on the model,
you might get lucky and find that it's removable.

It is. But there's no cap.

It's probably inside the compressor case.

....

Thanks. The diagram shows that the relay is replaceable. However, I
doubt that's the problem. It might be that the overload sensor is
tripping too early. Tear the relay and overload assembly apart, clean
all the junk out, clean the contacts, and look for damage. You might
get lucky.

A PTC relay is solid state, like the degauss posistor in a CRT TV set.

I fixed a 20+ year old Whirlpool with a bad overload. The repair
consisted of taking out the start relay (bouncing armature type) and the
bi-metal click disk overload switch, and gluing a GE brand PTC relay on
the side of the compressor with silicone glop and tie-wraps. (It includes
the overload function). Three wires: 1) power in from the main thermostat
and/or defrost timer, 2) start and 3) run wires to the compressor.

Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)