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Posted

What is the advantage of the mundorfs against the kemets?

 

I'd like to know that, too. Though with the large-quantity quote, it looks like they end up cheaper than Kemets.

 

Also, the spreadsheet doesn't specify which capacitances to sign up for, just a raw count.

Posted

"Spreadsheet updated with column for Carbon amp v5. Please make your changes there."

 

"No action is needed from you if you agree with this proposal - I will switch your order to the V5 board. Please respond to this thread if you prefer to stay with either the V2 or V3 board."

???

Posted

With the new development of the KGSSHV Carbon V5 board, I like to propose that the GB switch to use the V5 board and obsolete the V2 and V3 boards. V5 board basically allows the builder to choose between the original or new servo using the same board. For more details please read Kevin's posting #4970 and subsequent discussions over at the KGSSHV main thread. 

 

This will effectively drive down the amp board cost for both the V2 and V3 boards but definitely more so for the V2 boards.

 

No action is needed from you if you agree with this proposal - I will switch your order to the V5 board. Please respond to this thread if you prefer to stay with either the V2 or V3 board.

 

I will be posting the details of the quotes I obtained for the various boards soon. It's been a busy weekend for me and I need to make sure my calculation is correct.  

 

Would the v2 and v3 columns just be collapsed into the v5 column unless you hear otherwise? Would be odd for someone to want a v2 or v3 in place of a v5, no?

Posted (edited)

I actually don't see any point in manufacturing v2 or v3 boards. I think we should just all order v5 boards to get the lowest possible price. 

 

A major difference between the KEMETs and the Mundorfs seems to be the lifetime (18000h vs 2000h or 8000h)

Edited by insanity
Posted

Would the v2 and v3 columns just be collapsed into the v5 column unless you hear otherwise? Would be odd for someone to want a v2 or v3 in place of a v5, no?

 

That's what I intended. I thought it would keep things simple. 

 

Kevin can clarify, but I figure the whole purpose of the V5 is so we can obsolete V2 and V3 boards. I personally will be very surprised if someone would want the V2 or V3 board instead of the V5 but I don't feel right to not give the participants the option. Please do keep in mind, smaller quantity of boards will drive the per board cost high.

 

To avoid further confusion, I like to stick to what I proposed - "No action is needed from you if you agree with this proposal - I will switch your order to the V5 board. Please respond to this thread if you prefer to stay with either the V2 or V3 board."

Posted

Looks like I misread the datasheet of the kemet. Their lifetime seems to be similar. :-X

I actually don't see any point in manufacturing v2 or v3 boards. I think we should just all order v5 boards to get the lowest possible price. 

 

A major difference between the KEMETs and the Mundorfs seems to be the lifetime (18000h vs 2000h or 8000h)

Posted (edited)

What is the advantage of the mundorfs against the kemets?

 

 

I'd like to know that, too. Though with the large-quantity quote, it looks like they end up cheaper than Kemets.

 

Also, the spreadsheet doesn't specify which capacitances to sign up for, just a raw count.

 

As far as I remember NoPants asked for the Mundorf Caps option, and Kevin change the layout accordingly.

The Mundorf features their 4pin technology. Kevin says he uses the 4pin configuration on the cap before regulation, but shorts it on the cap at the output (uses the cap as a regular cap).

 

As for the advantage it probably boils down to personal taste and belief

 

As for the spreadsheet, the GB is intended for those who wants 680uF/550V.  I got quote on 470uF, 580uF(custom) and 680uF ....I guess the price difference isn't huge, so I guess most wants the 680uF? (have changed the spreadsheet to indicate this, and moved the Caps GB to separate sheet in the same workbook) ...but as KingOfSnake states: they are massive huge, and that goes for both the Kemet and Mundorf. Might be something to consider when planning for a chassie.

Edited by sorenb
Posted

If you scroll down in the datasheet of the kemet you also find the following:

Shelf Life
2,000 hours at +85°C or 30,000 hours at +40°C 0 VDC
Posted

I have a question about ordering the needed resistors from mouser. I want to use all vishay dale parts if possible. I had a BOM where I used mostly CMF60 resistors. Then I noticed that some of these i.e. 1k 10k had much higher prices than other values. My search continued and then I noticed that the RN60 resistors have a much better price than the CMF60. How is this possible? I thought this was more or less the same part, just with lower wattage and voltage ratings because of milspec. 

 

Anyone??

Posted

My guess would be that it is due to the volumes they order from the supplier, but I am not sure. I have also seen some cases where the 50ppm RN60s cost less than the 100ppm ones of the same value so there are some inconsistencies here and there :D

 

//UFN

Posted (edited)

From the data sheet (http://www.mouser.com/ds/2/427/cmfind-239942.pdf): “Vishay Dale Model CMF is also available as Military Qualified Styles RN and RL. See Vishay Dale’s CMF (Military RN and RL) datasheet (www.vishay.com/doc?31027) for the MIL-SPEC ratings / attributes. (Except for marking, the Industrial and Military versions are exactly the same).” (Emphasis mine.)

 

After reading this, I started buying whichever of the two is cheaper and available. :D

Edited by gepardcv
Posted

I am not sure if this applies to electrolytic cap or not

 

This is for  film cap

 

""VDC change on Mundorf capacitors on February 17, 2011

 

  •  
  • There has been a labeling change for Mundorf capacitors. This is labeling change only; there are no internal or technical changes.
  •  
  • Mundorf has changed the VDC rating for this capacitor from 800 VDC to 600 VDC (for security of operation in high-current, non-audio applications)
  •  
  • On newly made caps, Mundorf will change the label on the cap to indicate the new rating.
  •  
  • To reiterate, this is a label change only. There have been no changes in the manufacturing process or materials used for Mundorf capacitors.""
  •  
Posted

Somewhere there is a typo: the order code above for the 680 says +500 even though VDC says 550, and some vendors have the 680 listed as 500V, e.g. http://www.partsconnexion.com/capacitor_ele_mundorf_hv+.html

MLGO+500-680 680 ±20% 550 35 * 100 1.2 * 9 51.90

@Sorenb: would you know which is right

Following your link, I can see that they reference a Mundorf datasheet where the 680uF is rated at 550V ...like it says on the Mundorf site ....so I guess Mundorf stick to 550V ,ok?

Posted (edited)

I have attached the quotes I got from PCBnet (US) and iTEAD (China) here and also on my first post for all to review . You can see clearly the cost is very much affected by quantity.

Please keep in mind, the cost listed only contains the manufacture cost and shipping to me. It does not contain contribution to Kevin's order, packing material, shipping cost to you and PayPal fee.

I got quotes from 4 fab houses. I excluded quotes from two other China fab houses because their quotes are, overall, higher than iTEAD. One actually quoted 60% higher cost on the V2/V3 boards than PCBnet did.

Considering all factors, my intention is to go with PCBnet.

In a few days I will lay out logistics and start collecting payments. I will submit order to PCBnet soon as I receive all payments. It will take PCBnet roughly 10 days from the time I place the order to the time they are ready to ship the board out.

Please respond with your thoughts.

All boards are 2mm thick and 2oz copper, HASL finish, green PCB with white silkscreen.

post-4147-0-93342200-1437674316.jpg

Edited by mwl168

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