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Hi, I have an application that would benefit from a hermetic relief valve able to pop at maybe 50 PSI or lower. I don't know a lot about these components, but it looks like most of them pop at 200+ PSI - is a lower pressure commercially available? Thanks! Rob

Thanks a bunch for confirming - in the past I've found reference patterns a little fussy (sometimes the option doesn't come up when I go to pattern, and I usually can't figure out why), but the majority of my experience is in WF3.0 so maybe things have improved... J - Interesting perspective...

Hi All, First off, apologies if this has been asked before (seems likely), but I didn't see it. I'm evaluating Creo 1.0 v. Solidworks for a new drivetrain components company, so expect lots of "how do i" questions in trying to give Creo a fair chance... Question 1: Can I add features to an...

Hi John, I went to Honeywell Aero in Torrance for 2 years after undergrad, designing air bearings (= pretty much useless for automotive). I found my way into automotive by quitting and attempting to start a hybrid bus company from scratch - that was enough to get me into VW's Bay Area research...

Hi John, Where in Cali are you? I'm an automotive engineer in the SF bay area, crossed over from Aerospace 3 years ago. It's not the easiest move but certainly doable. Are you up in this region?

Hi Scotty, We will plot the fuses and design for the HRC to blow first. And the battery floats relative to the chassis, so all fuse locations should be equally valid. Cheers, Rob

Hi Scotty, Glad the conversation has transitioned from "you are a lunatic!" to "you are overdesigning!" :-) There are still two scenarios that concern me: #1 - Vehicle crash in which a short circuit is created somewhere inside the battery, upstream of the HRC fuse and contactor. With the...

Hi Scotty, Under most circumstances you are right, these fuses will just stand off the voltage of the parallel group they belong to (<5V). HOWEVER, if a massive short breaks all of the fuses in a parallel group AND the contactor + HRC fail to open the circuit, those fuses will stand off full...

Hi guys, and thanks for the input. It sounds like there is no obvious choice (as usual)... Which companies would be best to talk to for help with this kind of work? I'm in NorCal, but local isn't necessary. Cheers, Rob

Hi Scotty, I'd prefer not to give too many hints :) but 300A is a theoretical maximum based on the cell's voltage and internal resistance. At lower state of charge the cell voltage is lower and the peak fault current goes down. And you are close on the interconnection strategy - cells are...

Hi Scotty, We have one HRC fuse across the pack terminals, but in the event of a sub-pack event or even shorting failure of one cell within a parallel group we need localized backup fuses. The Tesla roadster for example has 6821 cells, individually fused... 6821 HRCs would be bigger than the...

Hi Gunnar, Hi David, DC battery powered system, ~300A is the max fault current. We are basically just trying to break the circuit in the event of a dead short. And it's automotive environment, so "yes" to vibration and corrosion. We have multiple fuses in parallel (to protect batteries in...

Sorry Gunnar, probably need to clean up my terminology when dealing with electrical folk - our group in automotive has different associations to the lingo :) Voltage: ~400V (medium to us, low to you) Current: ~90A (peak normal operating conditions, 60A continuous) Fuse: ~250A, 3s blow We...

Hi All, For starters, we are currently using an open fuse link designed specifically for this application by a major fuse manufacturer. Unless they are risking their entire reputation for our sake, it must be doable with high repeatability. I simply want to integrate that same fuse shape...

Whoops, meant to add that detail... let's say ~400V The primary reasons for wanting to go this way are cost and reliability - integrating a purchased fuse link into our system means having several critical electrical connections to attach it, which escalate cost and reliability concerns...

Hi All, I am doing some early thinking for a light (~60hp) EV application, trying to understand what the options are for reduction gearing and I could use some help! - We would like to achieve ~8:1 reduction between the motor shaft and the axle. Is this possible with a single stage helical or...

Hi Gents, I want to design a custom fuse link, and am trying to find resources to help understand the principles and design rules that govern it. The biggest question I have is: what design parameters determine the fuse voltage rating? Intuitively it seems like the distance bridged by the...

Hi All, I have an electrical application where I want to weld a common busbar to several contacts. I need the contacts to be flexible for tolerance/vibration considerations, but the main body should be thick busbar for high current. My perfect solution would be to "laminate" a thin sheet of...

Hi Folks - I'm new to CATIA and stumbling a lot, so thanks in advance for the help! I'm trying to design a piece with multiple pockets of different shapes (kind of like a plastic drawer divider). The pockets also need to be applied to both sides of the part - some digging material from the...

Hi guys, I'm doing various sizes, most are in the neighborhood of 5"x8"x20", one of them more like 8"x20"x40". I mentally ruled out billet already due to the size... pretty much anything that I can move to casting later sounds like it'll be horifically expensive in the prototype stage, and our...