purpose of capacitor

[framehvac]

Hold up I am not a serve tech I am a installer but I do know some service he ask what was a run capacitor & Start Capcitor was I told him I could be wrong that would not be the first time but if I am wrong then modern refrigeration and air condittionimg book is wrong because I looked it up in dictionary of techncal terms to make sure I was right were is NormChris he know everything he can tell us.

[condenseddave]

It depends. On a CSCR motor, the run cap is in the circuit connecting the start and run windings in series with one another.

On a PSC motor the run cap is in parallel with the "start" and the "run" windings.

Power is applied to the start winding through the start capacitor only until the switch (whatever form that might take) opens, then, the power is rerouted through the run capacitor. Actual line power is no longer applied directly to the start winding at that point, but current does flow through the winding.

The run capacitor takes the "place" of the start cap, after the motor is at or near full speed. (Often called 75% of full speed.)

And, eddy, I'm pretty certain that you do want to argue.

[condenseddave]

Originally posted by framehvac
Start Capcitor electrical storage device used to start and run circuits on many electric motors.

Run Capacitor a device that dissipates heat generated by a motor.

A run capacitor is the same exact thing as a start capacitor. It does the same exact type of work. It ONLY dissipates the heat from itself, which is generated as a side effect of it's constant charging and discharging. Nowhere in the Modern book, that I can see, does it refer to or describe the run capacitor as a "heat sink", which is what you infer with your second sentence.

The capacitors charge up and discharge energy, adn, for the millionth time, simply shift the phase angle of the power being applied to the winding to which they are attached, for the single purpose of "straightening out" incorrect phase angles.

[framehvac]

Nowhere in the Modern book, that I can see, does it refer to or describe the run capacitor as a "heat sink", which is what you infer with your second sentence.


Modern Refrigeration and Air Condittionimg book 18th edition pg.1159 run capacitor at the bottom of the page.


Run Capacitor a device that dissipates heat generated by a motor.

[condenseddave]

http://electronics.howstuffworks.com/capacitor.htm

[condenseddave]

Originally posted by framehvac
Nowhere in the Modern book, that I can see, does it refer to or describe the run capacitor as a "heat sink", which is what you infer with your second sentence.


Modern Refrigeration and Air Condittionimg book 18th edition pg.1159 run capacitor at the bottom of the page.


Run Capacitor a device that dissipates heat generated by a motor.

The newest copy I have is from 1992, and doesn't go to page 1159. I think Norm is going to tell you that that is wrong, also.

Is that from the glossary?

[condenseddave]

No edition number listed on my copy, but it appears to be the 6th.

Are you looking at "Modern Refrigeration and Air COnditioning" by Althouse, Turnquist and Bracciano????

[framehvac]

condenseddave
Professional Member

So did you see it it is in the book this is a book that they use in hvac schools I think you know your sh!t but is the book right or wrong I think a teacher would take Run Capacitor techncal term on a test & I think that is what this guy is looking for.

[framehvac]

No edition number listed on my copy, but it appears to be the 6th.

Are you looking at "Modern Refrigeration and Air COnditioning" by Althouse, Turnquist and Bracciano


Yes!6th edition time to update but if you have the 6th edition then I would say you know what you are talking about but in my book it does say that.

[fat eddy]

Dave your beating a dead horse, The Run and start windings are never in series they are paralell with one point in common that would be C

[bornriding]

Just for your info -
the shaded-pole & the resistance-start, induction run motors are the least torque producing motors of the single-phase class. That is because they do not use capacitors.
The shaded-pole motor uses a 'ring' attached to one pole to create a very small phase shift, with very little torque produced. The RSIR motor uses a winding of small wire to produce a large resistance to accomplish a small phase shift ( haven't plotted an RL circuit in a long while ) but I might could if need be.
Also, what do you think a cap-start motor is ??
basically the same thing as a RSIR motor but with a cap added for better starting torque - with a centrifugal switch to remove it.

And oh by the way, A compressor motor with a start & run capacitor operates with both caps in the system at the same time, but the start-cap is removed by the start-relay, leaving the start winding & the run capacitor in series together but in parallel with the run winding. The start & run windings are 'never' in series. Motor wouldn't work that way.

Electrician for 30+ years

[fat eddy]

Thank You BornRiding,

Now that we have gotten over that hurdle,can we now move on to how it looks a lot like a three phase motor.

Would someone please explain what a single phase to three phase converter does and what it does it with.

[framehvac]

fat eddy
Member

Registered: Feb 2005
Posts: 334
Thank You BornRiding,

Now that we have gotten over that hurdle,can we now move on to how it looks a lot like a three phase motor.

Would someone please explain what a single phase to three phase converter does and what it does it with.



I can't beleave you don't know that if you don't know then I am not goning to tell you.HaHa So just tell us?

[fat eddy]

Do tell please,

Enlighten me,

I do know the answer very well I want someone else to tell him so that he might beleive it.

[framehvac]

fat eddy
Member

Registered: Feb 2005
Posts: 335
Do tell please,


Can I phono someone?No I will take my 50/50 so give me my 50/50.

[snewman24]

In my edition of MR&A/C,published in 2000, it does describe a run capacitor on pg. 1159 of the glossary as "A device that dissipates heat generated by a motor." This is clearly in error and should have been caught by the editors. What they are trying to say is that the run cap has to be built to dissipate the heat it develops since it is left in the circuit while the motor runs, as contrasted to a start cap which is only energized for a fraction of a second and therefore doesn't have sufficient time to heat up. This is explained in the text on pg. 268.

[oilman52]

Capacitor law...all caps are wired to line voltage. All caps are wired to start winding.

[oilman52]

Anyone believe that one?

[fat eddy]

That is a false statement Oil

[oilman52]

Which cap. shell is plastic? Run or start?