Hi -
Did you ever find MSD SD-2 maintenance manual? I have one that works
great and would like to keep it that way . . .
Thanks
David A. Rice
me(a)davidarice.net
www.realhickorywind.com
--------------------------------------------------
If you think education is expensive - try ignorance.
--------------------------------------------------
> We used to have to put "motor run" capacitors on all our
> large equipment (3 phase) to get our power factor closer
> to one (unity). However, this system is a single phase
> system. I don't think the same issue is being addressed
> by the run capacitor.
It is, like the capacitor in flourescent light fittings the
run capacitor on a motor is (usually) just for power factor
correction and it matters not if it's 3 phase or single. The
give away is if it's across the supply or in series with a
separate winding. If it's across the supply then it's for PFC.
Lee.
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Well it's been a while, I just remembered something else about
run and start. We used to have to put "motor run" capacitors on all our
large equipment (3 phase) to get our power factor closer to one (unity).
It wasn't ever used in that situation for creating a second phase, as
we were using 3 phase motors. However, this system is a single phase
system. I don't think the same issue is being addressed by the run
capacitor.
joe heck
btw, I checked for "motor start" capacitor on google and got a nice
place to buy caps.
http://www.toad.net/~jsmeenen/boom.html is a nice picture of both
types of caps in a pool motor application
End of returned message
>From: vrs <vrs(a)msn.com>
---snip---
>
>Here is my problem with the claim that a couple of people have made, that
>these are "motor run" caps: They are clearly filled with paste, not oil (as
>some has been forced out through the emergency vent hole), and they seem to
>be marked with a "-" near one of the solder lugs. That strongly suggests to
>me that these are electrolytic "motor start" capacitors.
>
>Am I missing something?
>
> Vince
>
Hi
As I think Joe mentioned, the electrolytic capacitors are usually
used as motor run capacitors and not starting. These are non-polarized.
Starting capacitors are usually oil/paper ( newer don't have PCB's ).
This is because the starting capacitors require more current that
would blow up a run capacitor. Run capacitors are used to help
maintain efficiency of the motor while running. They help to
keep a rotating field and help to pull the inductive load back
to a resistive load from the AC side.
Dwight
>From: vrs <vrs(a)msn.com>
>
>> These are oilfilled AC capacitors. Not an electrolytic capacitor. They are
>> usually used together with the motor. Phase-shift capacitor for example to
>> generate a second phase on a single phase system.
>>
>
---snip---
>Hmm...Doesn't look oil-filled to me; more like a cream-colored paste. Looks
>just like an electrolytic which has blown crud out through the safety vent,
>which has then hardened over the years into a crust. Under the crust is a
>cream-colored substance with a texture like hardened toothpaste.
>
>I do know that motor start and motor run are different and incompatible.
---snip---
Hi
This is most likely an electrolytic capacitor, it is just
that it is a non-polarize electrolytic. These are special
purpose capacitors. If you place a regular electrolytic
capacitor into this circuit it would blow up.
You can use a pair of electrolytics mounted back to
back of equal value and something like a 10 meg resistor
in parallel with each to keep them balanced. The capacitor
values need to have the full voltage rating each and
the value needs to be 2 times the desired value.
Dwight
Motor-start and motor-run are different but the same. A motor-run
capacitor is AC and is connected all the time. A motor-start capacitor
is connected usually through a centrifugal switch (and starting winding)
so it is only connected during spinup. There are many motors that have
centrifugal switches and starting windings without caps. and most of
the caps used are fulltime, that is run caps. Now, my definitions may
not be everybodys definitions, but that was how I was brought up when
I did motor repair and rewound armatures. The giveaway was the
original spec stated 60 cycle, which is a motor capacitor. run or start
is not significant, but if it said 60 cycle, then it cannot be a DC
cap with plus and minus.
As stated in a previous message, the capacitor "creates" a second phase
so you can get the motor to spin. Too little or too much capacitance and
the created phase is not in the proper angle to provide the right
rotation. again, make sure you get at least the minimum voltage, and
getting a cap with more voltage spec is o.k., if you cannot match
the capacitance, I think I would err toward more rather than less.
Joe Heck
>From: vrs <vrs(a)msn.com>
>
>Hi,
>
>I've got an electrolytic I pulled from my TU56 drive because it had a big
>crusty electrolyte extrusion through the vent plug in the top. The
>capacitor is marked "SPRAGUE 100 MFD 55V - 60CY A5030". It is 2" in
>diameter and just over 4" tall, with two solder lugs on top. I think they
>are connected to the drive motors.
>
>I have looked for replacement electrolytic, but they all have way more
>capacitance or way more voltage rating, and are nowhere near the right
>physical dimensions. Is there a source for exact replacements?
Hi
Also, be careful, this sounds like a non-polarized cap. Rather
then checking with electronic supply companies, check with people
that do electrical and motor suppies.
Dwight
>
>If not, should I just get one with the right diameter for the mounting clamp
>and the right capacitance, but some huge voltage rating, or is the voltage
>rating more important and I should beef up the capacitance instead? Or do I
>have to get both those right, and substitute a little dinky device?
>
>Thanks!
>
> Vince
>
>
This is a real long shot, but hey...
Found this old posting from you, do you by any chance still have the
MEK-D@ manual?
I am trying to get copies of key sections.
Thanks
Eric
www.va3ep.net
------------------------------------------------------------------------
-------
John Honniball cctech(a)classiccmp.org
Tue Aug 13 09:09:38 2002
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------------------------------------------------------------------------
--------
Philip Pemberton wrote:
> A MOS Technology/Commodore KIM-1? Lucky you - I've been after a MOS
KIM for
> ages. They're like the proverbial rocking horse droppings (or gold
dust)
> over here in the UK. Same goes for the Synertek SYM-1.
Well, rare or not, I have both a KIM-1 and a SYM-1. No sign of
the AIM-65, though. I've also got a 6800 development board, the
Motorola MEK-D2.
--
John Honniball
coredump(a)gifford.co.uk
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