The capacitor in the original photo is 4.16.27.19. (the 4 is not shown). See page 6 of the databook above for an example of the label.
4.16.27 series are motor run capacitors.
4.16.27.19 is their 30uF model.

The Super Jolly Parts manual says "motor capacitor". It does not say "motor start capacitor".

As to why Espresso Parts NW says "start" capacitor - I don't know.
However, zooming in on the picture in the Espresso parts page shows a Ducati Energia 4.16.27.19 - a 30uF RUN capacitor.

Perhaps Espresso Parts are experts on Espresso equipment - but not so on motor capacitor ratings?

In any case, the OP is replacing a motor run capacitor (the capacitor in his original image) with a motor start capacitor.

Motor start capacitor usage (or why the heck is a start cap unsuitable?):

In the same catalog from Ducati, look at page 25. Electrolytic start capacitor series 4.12.80. Note the section "Duty Cycle" (copied below).



It is clear that a duty cycle of 1.7% wouldn't work if the motor isn't disconnected from the cap. 3 sec on/ 3 minute cooldown...

Obviously, this isn't the same cap as the one from Dayton and I have no idea what the rated duty cycle is for that capacitor. But my guess would be pretty similar.

That is the reason run caps are substantially more expensive than start caps.

Last point on the subject: People die every year because motor caps catch fires. Old refrigerators, freezers, laundry machines, etc.
As a point, the Grenfell Tower blaze was caused by a refrigerator. Everyone I know suspects it is the capacitor. So do these guys:
http://www.telegraph.co.uk/news/2017/06 ... ower-fire/

I am an electronics engineer. Caps have values in uF and voltage ratings. But once caps store energy - one must be careful. Power amplifiers can cause burns. I can show the disaster an exploding power cap in one channel of my amplifier:



But it is still low Power DC.

CAPACIATORS WITH MARKS (CE MARKS, VDE, KEMA KEUR, ETL, etc); and marks like X and Y etc - ARE SAFETY DEVICES. They carry and dissipate enough energy to cause a fire, explode, leak, etc - at best making a mess - and at worst - a real fire hazard.



If you are replacing something like these - use the same - or at least work out why it is marked as such (e.g. input filtering caps in switching power supplies). Albeit unlikely one would use an X or a Y cap not on a mains line....

AssafL:

I just love and appreciate your posts. You're such a wonderful (technical) resource!

Thanks so much!

Sincerely,

SR

AssafL, thanks for the explanation.

Here's what Grainger has to say about the Dayton start capacitor drtzali bought:

"These electrolytic, nonpolarized capacitors are designed for nomal
intermittent service on single-phase AC motor starting circuits."

AssafL wrote:It is clear that a duty cycle of 1.7% wouldn't work if the motor isn't disconnected from the cap. 3 sec on/ 3 minute cooldown...

...That is the reason run caps are substantially more expensive than start caps.

Substantially more expensive?

The start cap drtzali bought cost $11.
This run capacitor, made by the same manufacturer and on the same website, is only $2 more than the one he purchased:
http://www.sustainablesupply.com/Dayton ... 3-C1551605

I wonder though, do all run capacitors have the safety feature that the $9 run capacitor I linked from Mouser has?

I agree with AssafL that the capacitor should be replaced with the proper run capacitor. The start cap is an electrolytic which as I recall actually uses a chemical reaction to store energy, but school was many years ago and I may be mistaken in my memories. When mistreated electrolytic become bombs and explode or catch fire. Start caps are designed to dump a goodly amount of energy in a very short time and then be disconnected, while run caps are used continuously to smooth waveforms as the poles of the motor transition keeping the power factor as close to neutral as possible. This makes the motor appear as a resistance load rather than a reactive load which overall generates less heat and probably makes your utility meter spin just a little slower. Most of my experience over the years has been with three phase power systems so some of what I cited here may not be 100% correct but I don't think it is too far off base. Anyway my feeling would be to change out the capacitor to the correct one for the duty, it might save your house or even your life.

Wow. I really, really appreciate all the effort and vast knowledge of the posters who answered my question.

I embarrassingly admit that after reading it all I still don't really understand any of it.

So I'm going to make a simple request: can you guys tell me if the capacitor I installed is okay?

I probably run my grinder for a grand total of 1-3 minutes a day. If this is okay and I can keep the capacitor I installed please let me know. If I am in danger of blowing stuff up or setting stuff on fire please let me know and I'll get one of the other capacitors someone suggested.

Sorry for my dumbness and it's frankly a miracle I didn't blow myself up somehow already.

I also want to reiterate that my understanding of why this grinder needs a capacitor at all is simply to give the motor a jump start because since when the grinder is off there are still beans stuck between the burrs, so it needs that extra burst of energy to crush through those beans rather than the motor getting stuck/jammed because of them. So if that's the case then a start capacitor at least to me would make sense, because the whole point is just to get it started, and once it's started is able to grind the new beans that fall into the burrs just fine.

2$ more is 20% more. That is a lot on a BOM. Pricing for these things is very obtuse.

I likes your original recommendation. I like Kemet capacitors.

jpender wrote:I wonder though, do all run capacitors have the safety feature that the $9 run capacitor I linked from Mouser has?

Who knows. The datasheets for these things seem to be non-existent.

It seems like the Dayton capacitors are made in China by the Zhejiang Huizhong Industrial Trading company (based on the Grainger MSDS). Their brand is Huizhong, and I am having a tough time downloading datasheets.

https://cnhuizhong.en.alibaba.com/

I cannot find comparable units (e.g. searching for 6FLW2 model the OP purchased leads to nothing).

I can't resolve the links to their datasheets:
http://www.hui-zhong.net/upadimg/Run%20 ... 0SDS英文.pdf
http://www.hui-zhong.net/upadimg/Start%20capacitor.pdf

Maybe the links would work for you?

ira wrote:As a simpler or at least more clear on the consequences explanation, if you were to just plug a start capacitor into the wall it would likely explode or catch fire in a few seconds, while a run capacitor should in theory just happily sit there. Not to say you should try that, it might be that a start capacitor dies in a few seconds and a run capacitor instead lasts a few minutes, but conceptually a run capacitor should take that forever.

When I was much younger working in a small electronics assembly plant we used a small electrolytic capacitor whose legs were just the right distance apart and stiff enough you could plug them into an outlet. Every once in awhile, someone, after turning off the power to the workbenches would plug one of those into a now unpowered outlet. The first person to turn on the power the next morning would do it to a quite unexpected bang. Those were little, 1/2" diameter by an inch tall.

Reverse polarity on a Tantalum. AFAIK many special effects people use tiny tantalums as squibs.

Talking of pranks, used to charge tiny mylar caps to a few hundreds of volts and leave them on the desks at my high school. It was the first and last time I was ever punched by a jock. I deserved it...

I just got one a month ago for a dead Major I got on ebay (paid $120 and change for the major-e, my best find yet). Got a new capacitor for about $20 from Venia coffee. Call them.