The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

No that is small difference I don't think that will make any difference


"JIMMIE" wrote in message
...
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

"grumpy" wrote in :

No that is small difference I don't think that will make any difference


"JIMMIE" wrote in message
...
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie



20% is a a large difference. Not HVAC educated. Maybe for this app it's
negligible? One might ask why didn't they make it 20% less. Wouldn't that
be cheaper?

"Red Green" wrote in message
...
"grumpy" wrote in :

No that is small difference I don't think that will make any difference


"JIMMIE" wrote in message
...
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie



20% is a a large difference. Not HVAC educated. Maybe for this app it's
negligible? One might ask why didn't they make it 20% less. Wouldn't that
be cheaper?

Jimmie you can reduce capacitor in value as long as motor start up
but you can not increase, increase will cause start windings draw
excessive currents and eventually possible burn out, I have found
some motors may even run much cooler by reducing run cap. in value.

On Feb 10, 5:01*pm, JIMMIE wrote:
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

Why was he looking at the AC? If it is not running, then he might be
right. +/- 20% is about the maximum tolerance for thosse type of
capacitors.

On Feb 10, 8:49*pm, "hr(bob) "
wrote:
On Feb 10, 5:01*pm, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

Why was he looking at the AC? *If it is not running, then he might be
right. *+/- 20% is about the maximum tolerance for thosse type of
capacitors.

Seasonal check

Jimmie

On 2/10/2012 5:01 PM, JIMMIE wrote:
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

On Feb 11, 1:30*am, The Daring Dufas
wrote:
On 2/10/2012 5:01 PM, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

Ive never heard of anyone measuring the things before. While I am not
officially an HVAC tech, I work on radar systems, I wind up doing a
lot of the preventative maintenance on the ones at work and our tech
orders dont call for checking caps for capacitance. What they do call
for is measuring the start and run currents and recording them to
show trends and verifying the right capacitor is being used. If the
current is out of spec the first thing on the trouble chart is change
the cap. Over 25 years Ive changed a lot of them but never because I
measured the capacitance.. I know the environmental techs dont measure
capacitance either, they do check leakage current along with all the
other checks. I also know that even the best multimeters tend not to
be that accurate at measuring capacitance and I doubt like heck he is
carrying a capacitor analyzer around with him. Just didnt sound like a
good reason to fork out $100.

Jimmie

On 02/11/2012 07:37 AM, JIMMIE wrote:
On Feb 11, 1:30 am, The Daring
wrote:
On 2/10/2012 5:01 PM, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

Ive never heard of anyone measuring the things before. While I am not
officially an HVAC tech, I work on radar systems, I wind up doing a
lot of the preventative maintenance on the ones at work and our tech
orders dont call for checking caps for capacitance. What they do call
for is measuring the start and run currents and recording them to
show trends and verifying the right capacitor is being used. If the
current is out of spec the first thing on the trouble chart is change
the cap. Over 25 years Ive changed a lot of them but never because I
measured the capacitance.. I know the environmental techs dont measure
capacitance either, they do check leakage current along with all the
other checks. I also know that even the best multimeters tend not to
be that accurate at measuring capacitance and I doubt like heck he is
carrying a capacitor analyzer around with him. Just didnt sound like a
good reason to fork out $100.

Jimmie

That's really at the core of the issue -- HVAC techs can get away with
charging $100 to spend a few seconds changing a $10 part, so they have a
huge incentive to find "bad" ones.

JIMMIE wrote:
On Feb 10, 8:49 pm, "hr(bob) "
wrote:
On Feb 10, 5:01 pm, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

Why was he looking at the AC? If it is not running, then he might be
right. +/- 20% is about the maximum tolerance for thosse type of
capacitors.

Seasonal check

Jimmie

I'll bet it was the same last season. What is the tolerance written on it.
What temperature was is. They reduce when warm.

I say replace it. This might work if it's the same voltage rating. From
granger.

http://www.drillspot.com/products/50..._run_capacitor

Greg

On Feb 11, 2:35*pm, gregz wrote:
JIMMIE wrote:
On Feb 10, 8:49 pm, "hr(bob) "
wrote:
On Feb 10, 5:01 pm, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

Why was he looking at the AC? *If it is not running, then he might be
right. *+/- 20% is about the maximum tolerance for thosse type of
capacitors.

Seasonal check

Jimmie

I'll bet it was the same last season. What is the tolerance written on it..
What temperature was is. They reduce when warm.

I say replace it. This might work if it's the same voltage rating. From
granger.

http://www.drillspot.com/products/50...otor_run_capac...

Greg- Hide quoted text -

- Show quoted text -

If the AC works ok, leave well enough alone. These periiodic checks
are fine, but checking capacitance sounds like the tech was hunting
for some way to maake some $$ because nothing else was wrong.

On Fri, 10 Feb 2012 23:46:12 +0000 (UTC), Red Green
wrote:

"grumpy" wrote in :

No that is small difference I don't think that will make any difference


"JIMMIE" wrote in message
...
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie



20% is a a large difference. Not HVAC educated. Maybe for this app it's
negligible? One might ask why didn't they make it 20% less. Wouldn't that
be cheaper?

20% tolerance (and more) is normal for such capacitors. There really isn't
any need to make them better than that. If the motor runs, the capacitor is
fine.

On Sat, 11 Feb 2012 15:07:50 -0800 (PST), "hr(bob) "
wrote:

On Feb 11, 2:35Â*pm, gregz wrote:
JIMMIE wrote:
On Feb 10, 8:49 pm, "hr(bob) "
wrote:
On Feb 10, 5:01 pm, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

Why was he looking at the AC? Â*If it is not running, then he might be
right. Â*+/- 20% is about the maximum tolerance for thosse type of
capacitors.

Seasonal check

Jimmie

I'll bet it was the same last season. What is the tolerance written on it.
What temperature was is. They reduce when warm.

I say replace it. This might work if it's the same voltage rating. From
granger.

http://www.drillspot.com/products/50...otor_run_capac...

Greg- Hide quoted text -

- Show quoted text -

If the AC works ok, leave well enough alone. These periiodic checks
are fine, but checking capacitance sounds like the tech was hunting
for some way to maake some $$ because nothing else was wrong.
On the other hand, if the capacitor IS borderline, and the AC fails
to start on a very hot day next summer, good luck getting a tech to
look at it and fix it in a timely manner. The time to fix it is before
it quits, and when you do not need it.

On 2/11/2012 7:37 AM, JIMMIE wrote:
On Feb 11, 1:30 am, The Daring
wrote:
On 2/10/2012 5:01 PM, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

Ive never heard of anyone measuring the things before. While I am not
officially an HVAC tech, I work on radar systems, I wind up doing a
lot of the preventative maintenance on the ones at work and our tech
orders dont call for checking caps for capacitance. What they do call
for is measuring the start and run currents and recording them to
show trends and verifying the right capacitor is being used. If the
current is out of spec the first thing on the trouble chart is change
the cap. Over 25 years Ive changed a lot of them but never because I
measured the capacitance.. I know the environmental techs dont measure
capacitance either, they do check leakage current along with all the
other checks. I also know that even the best multimeters tend not to
be that accurate at measuring capacitance and I doubt like heck he is
carrying a capacitor analyzer around with him. Just didnt sound like a
good reason to fork out $100.

Jimmie

I check the darn things all the time because power surges and near
lightning strikes pop a lot of capacitors in AC systems. For folks
living in rural areas, I've been installing surge arresters on the
furnace and outdoor condensing units because of not only capacitor
damage but newer units have a lot of expensive circuit boards where
the older systems relied on relay logic controls. The more conscientious
HVAC techs use a capacitor tester on a regular basis because more damage
is caused to very expensive motors and compressors when the Chinese caps
go "POP!". Most of the HVAC techs who have a capacitor tester carry
this one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things. If you
have electrical/electronic repair experience, you should be able to get
your own 5uf capacitor at any motor rewind/repair shop, HVAC supply
house or W.W. Grainger. I always replace them with the 440 volt rated
capacitors.

TDD

" wrote in
:

On Fri, 10 Feb 2012 23:46:12 +0000 (UTC), Red Green
wrote:

"grumpy" wrote in
:

No that is small difference I don't think that will make any
difference


"JIMMIE" wrote in message

...
The HVAC guy told my wife the motor run capacitor on my AC unit
needed changing because it measured 4 instead of 5. He didn't say 4
or 5 what, I'm assuming uF. Does this really need to be replaced?

Jimmie



20% is a a large difference. Not HVAC educated. Maybe for this app
it's negligible? One might ask why didn't they make it 20% less.
Wouldn't that be cheaper?

20% tolerance (and more) is normal for such capacitors. There really
isn't any need to make them better than that. If the motor runs, the
capacitor is fine.




That's my philosophy with the Possum Van - if it runs it's fine.

On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this
one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the actual
capacitance that drops, rather than the ESR which climbs (the latter
being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make any
mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

"The Daring Dufas" wrote in message
...
On 2/11/2012 7:37 AM, JIMMIE wrote:
On Feb 11, 1:30 am, The Daring
wrote:
On 2/10/2012 5:01 PM, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

Ive never heard of anyone measuring the things before. While I am not
officially an HVAC tech, I work on radar systems, I wind up doing a
lot of the preventative maintenance on the ones at work and our tech
orders dont call for checking caps for capacitance. What they do call
for is measuring the start and run currents and recording them to
show trends and verifying the right capacitor is being used. If the
current is out of spec the first thing on the trouble chart is change
the cap. Over 25 years Ive changed a lot of them but never because I
measured the capacitance.. I know the environmental techs dont measure
capacitance either, they do check leakage current along with all the
other checks. I also know that even the best multimeters tend not to
be that accurate at measuring capacitance and I doubt like heck he is
carrying a capacitor analyzer around with him. Just didnt sound like a
good reason to fork out $100.

Jimmie

I check the darn things all the time because power surges and near
lightning strikes pop a lot of capacitors in AC systems. For folks
living in rural areas, I've been installing surge arresters on the
furnace and outdoor condensing units because of not only capacitor
damage but newer units have a lot of expensive circuit boards where
the older systems relied on relay logic controls. The more conscientious
HVAC techs use a capacitor tester on a regular basis because more damage
is caused to very expensive motors and compressors when the Chinese caps
go "POP!". Most of the HVAC techs who have a capacitor tester carry
this one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things. If you
have electrical/electronic repair experience, you should be able to get
your own 5uf capacitor at any motor rewind/repair shop, HVAC supply
house or W.W. Grainger. I always replace them with the 440 volt rated
capacitors.

*************** Good Policy**********************

TDD

In ,
grumpy typed:
No that is small difference I don't think that will make
any difference

No? A 20% change would make no difference? Whoosh!




"JIMMIE" wrote in message
...
The HVAC guy told my wife the motor run capacitor on my
AC unit needed changing because it measured 4 instead of
5. He didn't say 4 or 5 what, I'm assuming uF. Does this
really need to be replaced? Jimmie

In ,
hr(bob) typed:
On Feb 10, 5:01 pm, JIMMIE wrote:
The HVAC guy told my wife the motor run capacitor on my
AC unit needed changing because it measured 4 instead of
5. He didn't say 4 or 5 what, I'm assuming uF. Does this
really need to be replaced?

Jimmie

Why was he looking at the AC? If it is not running, then
he might be right. +/- 20% is about the maximum
tolerance for thosse type of capacitors.

So instead of 4, it migiht only be 3.2? Now you're really scrapiing bottom.

On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this
one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the actual
capacitance that drops, rather than the ESR which climbs (the latter
being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make any
mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is
the prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

TDD

On Sun, 12 Feb 2012 17:16:17 -0600, The Daring Dufas wrote:

On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this one or a
similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since
I also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the
actual capacitance that drops, rather than the ESR which climbs (the
latter being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make
any mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is
the prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

Sure, I don't doubt that they're under high stress and that testing of
capacitance is wise - I just wondered if it was different to the
electronics world, where high ESR normally warrants replacement long
before a meter capable of measuring capacitance alone might show up any
faults.

Maybe it's that high ESR just isn't an issue for motor start/run like it
(usually) is for electronic circuits, so capacitance is the only thing
there that techs really need to check.

cheers

Jules

On Mon, 13 Feb 2012 00:35:51 +0000 (UTC), Jules Richardson
wrote:

On Sun, 12 Feb 2012 17:16:17 -0600, The Daring Dufas wrote:

On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this one or a
similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since
I also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the
actual capacitance that drops, rather than the ESR which climbs (the
latter being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make
any mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is
the prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

Sure, I don't doubt that they're under high stress and that testing of
capacitance is wise - I just wondered if it was different to the
electronics world, where high ESR normally warrants replacement long
before a meter capable of measuring capacitance alone might show up any
faults.

Maybe it's that high ESR just isn't an issue for motor start/run like it
(usually) is for electronic circuits, so capacitance is the only thing
there that techs really need to check.

cheers

Jules
ESR, or eqeivalent series resistance, is a definite issue in
electronics where the capacitor is part of a tuned circuit -
particularly an R-C tank circuit.

Extra resistance throws all the timing out.

Not a big issue on a motor cap as far as I know

The Daring Dufas wrote:
On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this
one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the actual
capacitance that drops, rather than the ESR which climbs (the latter
being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make any
mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is the
prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

TDD

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

On Sun, 12 Feb 2012 16:09:47 -0500, "Twayne"
wrote:

In ,
grumpy typed:
No that is small difference I don't think that will make
any difference

No? A 20% change would make no difference? Whoosh!

No, he's right. That's a small difference, almost assuredly within the
tolerance of the cap.

On 2/12/2012 7:22 PM, gregz wrote:
The Daring wrote:
On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this
one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the actual
capacitance that drops, rather than the ESR which climbs (the latter
being what often causes problems* in electronic circuits)? The
description of the meter in the link you posted doesn't seem to make any
mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is the
prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

TDD

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

On 2/12/2012 9:28 PM, Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

The Supply houses carry them and here in Alabamastan, Alabama power will
install a meter socket surge arrester that is installed between
the meter and socket. It plugs in first, then the meter plugs into
the arrester.

http://preview.tinyurl.com/7bvfwn5

Lowe's stocks several brands of hardwired surge arresters and I've used
the Square D units before with good results.

http://preview.tinyurl.com/73xejpo

TDD

" wrote:
On Sun, 12 Feb 2012 16:09:47 -0500, "Twayne"
wrote:

In ,
grumpy typed:
No that is small difference I don't think that will make
any difference

No? A 20% change would make no difference? Whoosh!

No, he's right. That's a small difference, almost assuredly within the
tolerance of the cap.

Quickly looking at some spec sheets, most are less than 10% .

Greg

On 2/12/2012 10:29 PM, The Daring Dufas wrote:
On 2/12/2012 9:28 PM, Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the
suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

The compressor/condenser units are pad mounted. The pad, on the earth,
may be at a far different potential than the building earthing and
ground system if there is a very near lightning strike, or if there is a
strong surge current to the building earthing system.
The compressor ground will be at pad potential and the power wires will
be at the building potential, which could be thousands of volts different.

Same can happen with submersible pumps. At least some of them have surge
protection built in.


The Supply houses carry them and here in Alabamastan, Alabama power will
install a meter socket surge arrester that is installed between
the meter and socket. It plugs in first, then the meter plugs into
the arrester.

http://preview.tinyurl.com/7bvfwn5

Lowe's stocks several brands of hardwired surge arresters and I've used
the Square D units before with good results.

http://preview.tinyurl.com/73xejpo

TDD

I would rather have a service panel protector than one mounted on the
meter base. Meter base ones would likely have to come from the utility.

Neither will protect from the above.

--
bud--

Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

If you got the right kind of breaker, you can put this attached to breaker
box in parallel with HVAC, and will function whole house also. It can
attach at HVAC also.

http://www.drillspot.com/products/13...ge_Protectorii

Greg

gregz wrote:
Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

If you got the right kind of breaker, you can put this attached to breaker
box in parallel with HVAC, and will function whole house also. It can
attach at HVAC also.

http://www.drillspot.com/products/13...ge_Protectorii

Greg

This has stranded leads which is somewhat of a problem, you need a breaker
that will work on stranded leads. The last one I had, blew up. I also see
these have a lower clamping voltage than many. I see these on Holmes on
homes.
its better to protect HVAC locally. In the main box, you normally use a
dedicated 2 pole breaker.

Greg

On Mon, 13 Feb 2012 19:27:19 +0000 (UTC), gregz
wrote:

gregz wrote:
Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

If you got the right kind of breaker, you can put this attached to breaker
box in parallel with HVAC, and will function whole house also. It can
attach at HVAC also.

http://www.drillspot.com/products/13...ge_Protectorii

Greg

This has stranded leads which is somewhat of a problem, you need a breaker
that will work on stranded leads. The last one I had, blew up. I also see
these have a lower clamping voltage than many. I see these on Holmes on
homes.
its better to protect HVAC locally. In the main box, you normally use a
dedicated 2 pole breaker.

Greg

When the new system was installed I had them abandon the "old"
aluminum wiring that was in the wall (permit / inspection). They
left the old disconnect box in place and then installed a new
disconnect in the proper location (house had a drive-by inspection, so
the disconnect had to be moved).

New copper wire (I believe is stranded) in a new conduit and a new
breaker (lower amperage). The new disconnect has fuses as before did
not.

ISTR the tech saying the surge protector would be installed at / near
the disconnect box. He never mentioned the meter types of the panel
types. Before they come for the annual service I'll ask again.

We seldom have lightning. There is always a possibility of brown outs
(heat / high demand in the desert). We have not experienced a brown
out here at home, but I have seen one at my former work place.

Looks like choices a

- at the panel
- at the meter
- at the AC disconnect

hmmm :-\

Oren wrote:
On Mon, 13 Feb 2012 19:27:19 +0000 (UTC), gregz
wrote:

gregz wrote:
Oren wrote:
On Sun, 12 Feb 2012 20:39:16 -0600, The Daring Dufas
wrote:

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

My HVAC tech suggested a "surge" protector for my new unit. I asked
about a "whole house" suppressor, he said to put one on the
compressor. Got a link for the HVAC unit type? We seldom have
lightning strikes, but now it makes more sense -- just in case.

If you got the right kind of breaker, you can put this attached to breaker
box in parallel with HVAC, and will function whole house also. It can
attach at HVAC also.

http://www.drillspot.com/products/13...ge_Protectorii

Greg

This has stranded leads which is somewhat of a problem, you need a breaker
that will work on stranded leads. The last one I had, blew up. I also see
these have a lower clamping voltage than many. I see these on Holmes on
homes.
its better to protect HVAC locally. In the main box, you normally use a
dedicated 2 pole breaker.

Greg

When the new system was installed I had them abandon the "old"
aluminum wiring that was in the wall (permit / inspection). They
left the old disconnect box in place and then installed a new
disconnect in the proper location (house had a drive-by inspection, so
the disconnect had to be moved).

New copper wire (I believe is stranded) in a new conduit and a new
breaker (lower amperage). The new disconnect has fuses as before did
not.

ISTR the tech saying the surge protector would be installed at / near
the disconnect box. He never mentioned the meter types of the panel
types. Before they come for the annual service I'll ask again.

We seldom have lightning. There is always a possibility of brown outs
(heat / high demand in the desert). We have not experienced a brown
out here at home, but I have seen one at my former work place.

Looks like choices a

- at the panel
- at the meter
- at the AC disconnect

hmmm :-\

When my suppressor went, there was a storm. The lights went out, back on,
off, bang went the suppressor.

On Mon, 13 Feb 2012 17:31:40 +0000 (UTC), gregz wrote:

" wrote:
On Sun, 12 Feb 2012 16:09:47 -0500, "Twayne"
wrote:

In ,
grumpy typed:
No that is small difference I don't think that will make
any difference

No? A 20% change would make no difference? Whoosh!

No, he's right. That's a small difference, almost assuredly within the
tolerance of the cap.

Quickly looking at some spec sheets, most are less than 10% .

What caps are you looking at? Links please.

On 2/12/12 10:29 PM, The Daring Dufas wrote:

The Supply houses carry them and here in Alabamastan, Alabama power will
install a meter socket surge arrester that is installed between
the meter and socket. It plugs in first, then the meter plugs into
the arrester.

http://preview.tinyurl.com/7bvfwn5

Lowe's stocks several brands of hardwired surge arresters and I've used
the Square D units before with good results.

http://preview.tinyurl.com/73xejpo

TDD

Isn't having a good grounding electrode system critical for surge
arrestors to work properly?

On Feb 12, 9:39*pm, The Daring Dufas
wrote:
On 2/12/2012 7:22 PM, gregz wrote:









The Daring *wrote:
On 2/12/2012 10:52 AM, Jules Richardson wrote:
On Sun, 12 Feb 2012 00:50:46 -0600, The Daring Dufas wrote:
Most of the HVAC techs who have a capacitor tester carry this
one or a similar one:

http://preview.tinyurl.com/6p7c8ld

My own test gear tends to be more elaborate thus more expensive since I
also do circuit board repair work on a lot of different things.

So do motor capacitors typically fail in a way where it's only the actual
capacitance that drops, rather than the ESR which climbs (the latter
being what often causes problems* in electronic circuits)? *The
description of the meter in the link you posted doesn't seem to make any
mention of ESR, so I assume it's not relevant in motor appications?

* the real issue being that the capacitance can still check out OK on a
meter, but the high ESR will affect the circuit and cause it to fail.

cheers

Jules

Motor run/start capacitors are an extremely inexpensive commodity and I
tend to look at them like disposable batteries here lately because so
many of the Chinese caps fail. It seems like every little hit from a
voltage spike coming from the electrical service punches holes in the
dielectric of the darn things. A simple test on every service call is the
prudent thing to do because of the nature of the equipment. I have
seen sources for very high quality American manufactured capacitors but
they're very expensive. o_O

TDD

Last year I got some kind of surge/ spike that took out the suppressor I
had on my compressor line. I installed a new one again. Ac is ok.

Greg

That's why I recommend surge arresters on HVAC equipment. Around here in
the summer months is when we have a lot of thunderstorms and the
darn lightning strikes occur when the AC is running wide open. Voltage
spikes travel a long way from a strike and of course power may cut in
and out a lot so I always install a anti-short cycle timer to protect
the compressor from slamming on and off when under load. Most electronic
thermostats have the timer built in but there are a lot of mechanical
thermostats out there.

TDD

Picked up a new cap today and changed it out. Checked the cap and it
was 4.8uF out of 5. I can measure within 1%. It did need changing
though but not for the reason the tech mentioned. The rivet holding
the connectors was sloppy loose. Also found the wire dress a mess.

Jimmie

On Feb 11, 1:30*am, The Daring Dufas
wrote:
On 2/10/2012 5:01 PM, JIMMIE wrote:

The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A new capacitor that size is not that expensive and from the value of
5uf I have to assume it's the run capacitor for the blower or condenser
fan motor. If the tech tries to charge you more than $20.00 for the cap
which wholesales for $3 to $5, he may be trying to rip you off. The cap
value dropping from 5uf to 4uf is quite a bit and could be an indication
of a capacitor that's failing. I've had to replace a lot of defective
capacitors for customers in the last decade because all the damn things
are coming from China. If you decide to have it replaced, ask the tech
to replace it with a higher voltage rated capacitor. If it rated at 370
volts AC ask the tech to install one rated at 440 volts AC.

TDD

Picked up a Dayton cap at local supplier. One that was in it was a
Supco. The Dayton was a lot more expensive than the Supco. Are they
better? I use a Dayton motor on my tablesaw and it is probably 30
years old and still going.

Jimmie

On 2/13/2012 9:49 PM, Dean Hoffman wrote:
On 2/12/12 10:29 PM, The Daring Dufas wrote:

The Supply houses carry them and here in Alabamastan, Alabama power will
install a meter socket surge arrester that is installed between
the meter and socket. It plugs in first, then the meter plugs into
the arrester.

http://preview.tinyurl.com/7bvfwn5

Lowe's stocks several brands of hardwired surge arresters and I've used
the Square D units before with good results.

http://preview.tinyurl.com/73xejpo

TDD

Isn't having a good grounding electrode system critical for surge
arrestors to work properly?

For a service entry protector earthing has to be reasonably good.

If you have a strong surge, 1,000A, to earth, and a quite good 10 ohms
resistance to earth the building 'ground' system will rise 10,000V above
'absolute' earth potential. Much of the protection is actually that all
the wiring - power, cable, phone, dish, ... - rises together.

The NIST surge guru wrote "the impedance of the grounding system to
`true earth' is far less important than the integrity of the bonding of
the various parts of the grounding system."

That is, work on short ground wires from entry protectors from phone,
cable, ... to a common connection point on the earthing system. That
will greatly help keep all the wiring at the same (elevated) potential.

You could protect with no earthing. Throw your empty beer bottles out in
the yard. Build a metal shed on top of the bottles. Bring
power/phone/cable into the shed next to each other with surge protectors
connected to the shed (but not earth). The voltage between wires in the
shed is safe and earthing was not used for protection.

Point-of-use protectors don't primarily earth a surge. They limit the
voltage on all appropriate wires to the ground at the protector.

At a pad mounted compressor/condenser I would connect a surge protector
to limit from the power wires to the enclosure.

At a furnace I would do the same and make sure the control circuit is
grounded to the furnace.

Control wires from the furnace to the compressor/condenser are a
possible problem (during an 'event' the ground potential at furnace and
compressor unit may be very different). Control wires are probably
isolated enough at the compressor from the compressor ground.

--
bud--

On Mon, 13 Feb 2012 21:49:29 -0600, Dean Hoffman
" wrote:

On 2/12/12 10:29 PM, The Daring Dufas wrote:

The Supply houses carry them and here in Alabamastan, Alabama power will
install a meter socket surge arrester that is installed between
the meter and socket. It plugs in first, then the meter plugs into
the arrester.

http://preview.tinyurl.com/7bvfwn5

Lowe's stocks several brands of hardwired surge arresters and I've used
the Square D units before with good results.

http://preview.tinyurl.com/73xejpo

TDD

Isn't having a good grounding electrode system critical for surge
arrestors to work properly?

Not necessarily. The idea is to keep everything at the same
potential. Think of a boat on the water.

On Feb 10, 5:01*pm, JIMMIE wrote:
The HVAC guy told my wife the motor run capacitor on my AC unit needed
changing because it measured 4 instead of 5. He didn't say 4 or 5
what, I'm assuming uF. Does this really need to be replaced?

Jimmie

A motor run capacitor has a leeway of plus/minus 10-15% in
microfarads (generally) without causing any problems with what its
hooked up to. This very low capacity Capacitor would be inexpensive
to replace if it needed it ...and just a matter of 3 push on wires
most of the time.