Dc power supply in cnc not working

[shelby5041]

Re: Dc power supply in cnc not working

and it makes me mad too becasue i screwed up...and now i have to replace a high quality component with crap made in china

i put the wires off to the side pos to one side and neg to to other side so that when i hook bnoard back up i just hook up terminals accordingly...but since i have been working on this machine for a few days the wires got moved around by accident and when i went there today to hook the board back up ...BOOM!!!!!

this cnc machine is ...was entirely made in USA even all the electronics

oh well

[shelby5041]

Re: Dc power supply in cnc not working

would it be ok to get a cap with diff uf value or do i need to stick with 4800uf? i know i can get higher voltage if better availability

[CapLeaker]

Re: Dc power supply in cnc not working

Mallroy = Cornell Dubilier - CDE
you find them on digi or mouser. Probably $40 or so.

[shelby5041]

Re: Dc power supply in cnc not working

awesome thanks i found them at mouser $40 plus shipping

quite costly but thats what i get for screwing up

[eccerr0r]

Re: Dc power supply in cnc not working

Where's pictures of capacitor gore!

[shelby5041]

Re: Dc power supply in cnc not working

hi

i dont know
i posted photo yesterday and it showed up and then now its gone

will have to see if i can post anohter day as the photo is not on my pc

one question though...this capacitor is about $40 new...if i can find a used one for real cheap under $10 would it be worth buying?

as i said i wont be using this machine much at all ..maybe once in a great while....to me a good working used one wold be ok..just wanted some input from pros

[Per Hansson]

Re: Dc power supply in cnc not working

$28 on this one, I'm not sure where the free shipping kicks in for US customer but I believe it is not that much higher?
https://www2.mouser.com/ProductDetai...BL%252BQXG1g==

[shelby5041]

Re: Dc power supply in cnc not working

hi hanson
i saw that one but its wrong dimensional size and would require some modifying which i dont want to do

i need 22mm screw holes spacing and 2in diameter

mouser shipping is $9 extra

[Per Hansson]

Re: Dc power supply in cnc not working

How about this then? Quite cheap too.

https://www.mouser.com/ProductDetail...5aE5RRng%3D%3D

[eccerr0r]

Re: Dc power supply in cnc not working

I don't understand this quote on mouser's website: "Quantities greater than 33 will be subject to minimum order requirements."


???

[shelby5041]

Re: Dc power supply in cnc not working

hi hanson

its a bit lower than 4800uf but im sure it would be ok considering the application
but it may be too tall not sure..original is 80mm tall



its possible it would fit..i may have to do some measuring..i have restrictions on height and diameter due to where its located unless as i said i do some modifyng which im not wanting to do

thanks

[Per Hansson]

Re: Dc power supply in cnc not working

I don't understand this quote on mouser's website: "Quantities greater than 33 will be subject to minimum order requirements."


???

They have 33 in stock, I think it means if you order more than 33 the additional ones you will not get the lower break prices on.

[redwire]

Re: Dc power supply in cnc not working

I would bite the bullet and get the $40 part because newer or cheaper parts are smaller and will not fit the PC board 22mm screw spacings.
Cornell Dubilier - CDE CGS482U075V3C 4,800uF 75VDC $39 at Mouser

I don't see the high current path from the cap (+) to the load. Would need more board pictures to see where the voltage loss is occurring. There might be a fuse, open-connection etc. which is what I'd be looking for.
The LM338 would be OK if the output measures 5VDC for the logic circuits. They might act as the master switch for the 42VDC, if there is a relay or something.
So far I don't see any 42VDC regulator and it could be unregulated if powering high current solenoids etc.

[shelby5041]

Re: Dc power supply in cnc not working

Hi redwine
Thanks
I didnt want to spend 50$ total inc shipping....however i did get lucky and found exact part number on ebay used

I typicslly eould never buy a used cap but sibce this one is so costly new i made an exception

I only paid $7.50 snd free ship... i wanted to buy this new one but its 1in taller..wouldnt fit https://www.ebay.com/itm/14409611372....c100167.m2940

It was the only one on ebay that matched part number and made in USA

Plus ...there is risk that the ps could be bad...so spending 50$ on a non returnable item could be 50$ out the window

And also no fuses in circuit....i measured 44v at big cap so the issue would be the lm338 or a diode in citcuit since thats all thats in between cap and output ....my only concern is if the lm338 is bad if some other component blew the lm338...will see what happens when i get the cap and lm338...both ordered

)

[shelby5041]

Re: Dc power supply in cnc not working

Here are pics redwine

[shelby5041]

Re: Dc power supply in cnc not working

Am i right to assume a mallory/cornell made in usa capscitor is as good or better quality .........as compared to made in china versions? And surprisingly the mallory csp is only rated for 2000hrs ....can they last longer than 2000hrs?..i would have thought it would be 5000 or maybe 10000 hour rated.

[sam_sam_sam]

Re: Dc power supply in cnc not working

They can those ratings are based on using at the rated voltage maximum and at maximum temperature rating if used with in the normal range rating it should last a lot longer

[stj]

Re: Dc power supply in cnc not working

the rated hours is at maximum temperature, voltage and ripple.
it's a minimum life.

[eccerr0r]

Re: Dc power supply in cnc not working

Those are lifes at the rated temperature. Life of capacitors are significantly improved if you keep them cool, the rule of thumb is double life each time you keep them 10°C cooler. Note that capacitors generate heat.

[shelby5041]

Re: Dc power supply in cnc not working

Great info thanks...i think my decision to buy the used cap should be fine for my situation...there is a nice 4in 12v cooling fan inside the enclosure so that should keep the cap a bit cooler than normal