Electrical Engineering

5:39 AM

@ThePhoton Still not 2 weeks

6:33 AM

morning

PlasmaHH

7:32 AM

@W5VO there is not much common for the eu, it is all different for the single countries. In Germany though you always get three phase from the utility company. That means three phase for single houses, and whatever the landlord of your apartment building decided, which often means three phase too, in case water heating is done with electricity

MickLH

8:07 AM

luckyyeeee

8:54 AM

@jippie yup

2 hours later…

PlasmaHH

11:01 AM

@crasic would be fun if I printed out all the code I wrote in this company...

4 hours later…

Rami Aqqad

2:44 PM

Hello I have a question in NGSPICE can I ask here?

W5VO

3:14 PM

@RamiAqqad probably, what are you trying to do?

electronics.stackexchange.com/questions/188821/… <- someone has a lot of work ahead

3:51 PM

@W5VO dilbert episode? Having been assigned a task that you don't have the tools, knowledge and system docs for?

4:01 PM

@crasic I used to do that, but cubicles keep shrinking and storing binders of old project information is discouraged around my office.

Sometimes it leads to engineers spending longer debugging a problem, but I guess that's a trade-off my management has chosen to accept.

Rami Aqqad

@W5VO, I have recently compiled CUSPICE but unfortunately, I faced ERROR
Using KLU as Direct Linear Solver
Using CUSPICE (NGSPICE on CUDA Platforms)
Segmentation fault (core dumped)
---------
I was using same input file in NGSPICE and it was working fine!
---------
***spice file
.options temp=125 C
vdd vdd 0 1
icritcharge A 0 DC 0 AC exp(0 -1.17329607021669e-05 15p 33p 0 161p)

.include 22nm_HP_degraded_m1.pm
.include 22nm_HP_degraded_m3.pm
.include 22nm_HP_degraded_m2.pm
.include 22nm_HP_degraded_m4.pm

eevBLAB #13 - Buying Youtube DISLIKES! - The Batteriser

4:22 PM

The batteriser people really do know what to waste their money on.....

►

1 hour later…

PlasmaHH

5:40 PM

They get enough for free, so they do others the favor to buy some ;)

@Asmyldof Yeah it is amazing what you can buy on Internet. I bet you can buy EE.SE rep too.

@jippie Oooo, but can you sell it?

My rep must be worth at least $0.10!

@ThePhoton I'll happily upvote you +30 rep for 5$

@jippie I told you, I want to sell, not buy.

my goodness what language some people use ... (spam flag)

5:48 PM

@jippie where?

I'll give you 5$ if you upvote me +100 by the end of the week

no wait, that is wrong :-/

no definitely I am the one wanting to make money here

W5VO

6:17 PM

@RamiAqqad Try running something really simple first, like a transient simulation of an inverter. Make sure you can actually run it first. If you can't, then your best recourse is probably with the ngspice folk

@jippie Yeah, and the case is pretty severe as well

@Asmyldof I'm waiting for the downvotes

6:58 PM

slightly off topic guys ...

if a household machine is defective and needs repairs

is there some rule of thumb what part may cost

to be economically viable?

to be more specific: a 20yr old washing machine ... if a new one costs say 800€, what would be reasonable to spend on parts?

W5VO

Probably involves the likelihood of further failure, perhaps a valuation of the current machine

and if you want to be clever, any difference in operating cost of the new machine

and how much your time is worth ;)

@W5VO I asked a repairman for tomorrow morning, but I'm in doubt now if that was a good idea since the machine is 20yrs old.

I know the valve is broken ~30 - 70€

the guy repairing it .. say 60€

I just realised one of the buttons (Start) is getting old too ..

Also I discovered that I can manually fill water into the machine, changing fixing priority from "top priority" to "above medium priority"

Al Longley

7:40 PM

If I had to come up with a rule of thumb:

Manually fill it until the next thing breaks on it, and then figure out how to manually perform the function that the broken thing performs, repeat this process until you can justify the price of a new one in comparison to the amount of manual labor it requires to wash your clohes

1 hour later…

8:41 PM

@jippie Jippie it depends on the condition of the rest of the machine

If a part can be considered a consumable then replacing it may be worth it

E.g. a motor bearing that has a lifetime of 10 Yrs, while the rest of the Assy has a lifetime of 30 Yrs, replacing the bearing gives you an effective lifetime extension of 10 Yrs, if a new machine contains the same part then the repair may be just as effective as purchasing a new machine

@crasic I'm a bit afraid of other consumables that last about 20yrs.

Right so it depends on what breaks

and the cost of the repair will be at least 10% of a new machine

I would approach it from a risk analysis perspective

Expected lifetime of the machine, lets say 10 more years

the youngest forum entries mentioning my machine date from 2013 :-p

8:47 PM

X = Expected Number of additional failures*average cost of repair

e.g. the capital cost of the machine over the next ten years

Y is the cost of a new machine with an expected problem free lifetime of 10 years

if X > Y then a repair is not worth it

new machine will probably be more efficient too :-/

anyways hints / tips / thoughts are welcome, but it's way past my bed time.

Yes, so the total cost of this machine for 10 years is

The cost of the current repair + the expected repair cost over the 10 years + operating costs (water and heat for some average use case) for 10 years

if that is more than the cost of a new machine and the operating costs of that new machine (which may be more resource efficient) then its worth replacing it

hmm

But on the other hand money is not free, if you spend risk $100 making this repair and a new machine is $1k then the utility of that $900 over the next 10 years may be worth it

but if it fails in 2 months with additional cost then it was an expensive repair. \

8:50 PM

but since we are talking small dollars this is not necassarily an ssue

Yes that is the risk

whereas a new machine has an 8 year warranty

The big unknown is the likelihood of other parts failing

@crasic yeah I know :-/

Curious wha kind of magic unicorn-farts yoiur machine is made of

My washer-dryer-combo was € 480 about 6 years ago

If you spend $1000 over 10 years repairing it vs $1000 today, you have time to make interest on that money

8:52 PM

it is big and white

@Asmyldof you would probably fix it yourself :-p

E.g. scenario A you put $1k in a repair account that you would have spent on a new one, while you wait for the next part to fail you earn a few % over the years to offset that cost, you also have available liquidity for other issues

Probably, if it were worth it, which it probably wouldn't

but I digress into business land

All that being said, I think that simple repairs <$100 on appliances are overall worth it

unless you have a strong suspicion that its EOL and will die regardless

Replacing a fan, button, motor, etc.

@crasic the start button is getting bad as well

;o)

Economic life on something like a front loading washing machine is 10 years, 15 if it was a good one

8:55 PM

seems an important button

I got this one early 1996

Bearings, springs, all wear down

@Asmyldof I would suspect that the components themselves may be better than that. A nice 3 phase motor not overloaded should be a beast for 20/30 years

but the system wears down and failing parts tend to take other parts with them

with increased stress

there is little stress when the valve doesn't open :-p

In this exact scenario, the water level sensor on my washing machine broke and it would ocasionally overflow

It's not the motor that should be the cost. The motor is dry and if well engineered can last a century

8:57 PM

$30 assembly on ebay, but that is a 10 year old machine