a friend is having problems with the pump in an outdoor pool.
Apparently the motor ran one day then the next day it would not come
on. mains supply is good. He suspects a capacitor - which seems to be
16uF 400v , from the motor. I've seen it, quite a chunky thing with a
small threaded screw coming out of it for attachment and a plastic
body. it's about the size of the mains filter caps in 1970s t.v.s

I had never seen a 16uF cap before, and I am surprised at this size.
Is it likely to be an electrolytic? I presume replacing this is a
good place to start. Any thoughts?
-B

b wrote:
a friend is having problems with the pump in an outdoor pool.
Apparently the motor ran one day then the next day it would not come
on. mains supply is good. He suspects a capacitor - which seems to be
16uF 400v , from the motor. I've seen it, quite a chunky thing with a
small threaded screw coming out of it for attachment and a plastic
body. it's about the size of the mains filter caps in 1970s t.v.s

I had never seen a 16uF cap before, and I am surprised at this size.
Is it likely to be an electrolytic? I presume replacing this is a
good place to start. Any thoughts?
-B
IT's a AC (Non polarized cap) and you can't always assume a cap.
You can look for vented internals at the base ect.

Also a good test would be to see if the motor is humming when started.
if this is the case then the CAP maybe opened but I would first check
that. The caps are not cheap.

Use a CAP meter or your DMM which many have a C testing function.
check for DC shorts and then test for Value using a Cap function .

Also, some motors use a centrifugal switch that sits in the head of
the motor. The actuator/switch could be stuck or broke. You can
determine this
by using an ohm meter from the windings verses the other windings..

etc..


http://webpages.charter.net/jamie_5"

"b" wrote in message
...
a friend is having problems with the pump in an outdoor pool.
Apparently the motor ran one day then the next day it would not come
on. mains supply is good. He suspects a capacitor - which seems to be
16uF 400v , from the motor. I've seen it, quite a chunky thing with a
small threaded screw coming out of it for attachment and a plastic
body. it's about the size of the mains filter caps in 1970s t.v.s

I had never seen a 16uF cap before, and I am surprised at this size.
Is it likely to be an electrolytic? I presume replacing this is a
good place to start. Any thoughts?
-B


The capacitor is almost always suspect in case of an AC motor failure, however,
it's not the only thing that can cause problems. As a starting place, I suggest
that you read the FAQ at
http://www.metalwebnews.com/howto/el.../elec-mtr.html. It will give you some
theory on motor operation and some troubleshooting tips.

If the motor has a centrifugal start switch, then that's the first thing to
check, since it's the easiest thing to get to on your motor. Open the end bell
on the opposite end of the shaft and make sure the contacts are in good
condition. If they are burned or badly pitted, they are probably not making
contact. This will surely prevent the motor from starting.
Next, test the capacitor with an ohmmeter. It should not have a steady low
(less than a few thousand ohms) resistance, but when the meter is first
connected, the reading should read very low, then commence a steady rise in
resistance, ending in extremely high resistance.
Last thing for you to try is check the continuity of the motor's windings. The
web page above will give you a number of possible wiring configurations (you'll
have to determine which applies to your motor).

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Experience: What you get when you don't get what you want

On Sun, 15 Jun 2008 10:11:10 -0700 (PDT), b
wrote:

a friend is having problems with the pump in an outdoor pool.
Apparently the motor ran one day then the next day it would not come
on. mains supply is good. He suspects a capacitor

Why does he suspect it?

- which seems to be
16uF 400v , from the motor. I've seen it, quite a chunky thing with a
small threaded screw coming out of it for attachment and a plastic
body. it's about the size of the mains filter caps in 1970s t.v.s

I had never seen a 16uF cap before,

Limited experience?

and I am surprised at this size.

Too small or too large?

Is it likely to be an electrolytic? I presume replacing this is a
good place to start.

Good for the person who sells you a new capacitor. Probably not good
for you, however.

Any thoughts?

More information, what diagnostic work have you done yet?

-B

In article ,
Jamie t wrote:

b wrote:
a friend is having problems with the pump in an outdoor pool.
Apparently the motor ran one day then the next day it would not come
on. mains supply is good. He suspects a capacitor - which seems to be
16uF 400v , from the motor. I've seen it, quite a chunky thing with a
small threaded screw coming out of it for attachment and a plastic
body. it's about the size of the mains filter caps in 1970s t.v.s

I had never seen a 16uF cap before, and I am surprised at this size.
Is it likely to be an electrolytic? I presume replacing this is a
good place to start. Any thoughts?
-B
IT's a AC (Non polarized cap) and you can't always assume a cap.
You can look for vented internals at the base ect.

Also a good test would be to see if the motor is humming when started.
if this is the case then the CAP maybe opened but I would first check
that. The caps are not cheap.

About $7. Many people would call that cheap.


Use a CAP meter or your DMM which many have a C testing function.
check for DC shorts and then test for Value using a Cap function .

Also, some motors use a centrifugal switch that sits in the head of
the motor. The actuator/switch could be stuck or broke. You can
determine this
by using an ohm meter from the windings verses the other windings..

etc..

The centrifugal switch contacts on my compressor motor were
intermittent, and I ended up replacing the switch. But I don't consider
the few dollars I spent on new caps as a first attempt, to have been
wasted.

Smitty Two ha escrito:
etc..

The centrifugal switch contacts on my compressor motor were
intermittent, and I ended up replacing the switch. But I don't consider
the few dollars I spent on new caps as a first attempt, to have been
wasted.

thanks for the useful replies.- part of the problem here is that I'm
working 'blind' , not having seen the setup or been able to check it
out for myself, I don't even know what type of motor it is or how old
etc. All I've seen was the cap that was shown to me briefly. I'll try
and get out there to take a look for myself and post back. meanwhile
will follow up on the links and advice posted here.
cheers, B.