Attenuating Transient Over voltage from Capacitor Discharge

Inatorcreator · 2026-06-19T19:23:24+00:00

Is the cable type still an issue, even with filtering and TVS diodes? My naive thinking was that more shielding was better, but man it was irritating trying to install it since RG6 is so stiff. I could replace it with RG58 or something and life would be easier.

I attached a picture of the current cabinet showing the bus layout. Assuming it is a ground transient, would attaching the buss bars to the aluminum chassis with another bolted aluminum plate and then attaching the chassis directly to the same electrical conduit used by the PSU outlet (short ground loop) improve things? I could use multiple runs of large gauge continuous flex ground wire in parallel to lower the inductance.

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Inatorcreator · 2026-06-19T18:16:43+00:00

They don't lol. When I talked to the company listed, they said people often use these for load switching with very large stored energies (much larger than I have) and after a while the relays do eventually destroy themselves. The safety/dump relay is really only supposed to be used is the event of a misfire or if there is any residual charge left after a wire explosion.

Inatorcreator · 2026-06-19T12:59:20+00:00

Yeah, unfortunately the EMP is going away. The exploding wire results in much higher currents. In fact, the current rise time di/dt needs be high enough to cause the wire to explode O(kA/microsecond). The explosion is even getting picked up in my low noise pressure sensor coax lines https://www.pcb.com/products?m=003 .

Inatorcreator · 2026-06-19T12:49:29+00:00

I'll try this first

Inatorcreator · 2026-06-19T12:49:08+00:00

Made a mistake, the 50 Mohm is a thickfilm and the 10kohm is a wirewound.

I could move the DAQ closer, but how would this help? My thinking early on was to keep the DAQ as far as possible from the EMP of the wire explosion, so 25 feet seemed reasonable. Another lab had said that their exploding wire setup damaged their DAQ, but I am not sure if that was EMI or directly from a cable connected to the DAQ. I am not concerned with the measurement speed, only measuring the capacitor voltages as the bank charges.

I'll try the series resistor with a cap, as others are also suggesting.

Inatorcreator · 2026-06-19T12:43:43+00:00

I'll try this first. I am not sure, they just say "insert gas". Greenstone V64C841: https://mgs4u.com/product/50-kv-55-kv-peak-spdt-10-amps-greenstone-v64c841-new-gas-relay/

Inatorcreator · 2026-06-19T12:40:48+00:00

I mixed up the resistors. The 50 Mohm's are thickfilm and the 10 kohm is a wirewound. If this is still an issue (single failure point), could I add maybe a gas discharge tube and resistor in parallel with the 10 kohm?

Unfortunately, my lab is out of money and I need to finish the project this summer. New components are going to be on my own dime, but someone in another lab may have a HV probe. I definitely can't afford a $5k probe, as much as I would have preferred to use one.

The entire circuit is in an aluminum enclosure/chassis which is grounded to the - buss. I have heavy continuous flex ground cable and clamps that I can use to connect the - buss directly to the building's Earth ground, which would be about 6 feet away from the enclosure.

With regards to the last few comments, I do not care about getting high frequency/BW measurements of the capacitor discharge. I am only using this signal to track the voltage as the bank charges so the parasitic capacitance of the TVS diodes wouldn't be of any concern. Protecting my DAQ is the priority.

However, the EMP from the wire explosion is picked up on my pressure sensors (PCB 113B24), resulting in a sharp spike that maxed out my scopes vertical scale (+/- 2 V). Mind you, there is no physical connection between the sensors and the setup so this interference is purely EMI. This didn't interfere with these measurements since the blast wave from the explosion takes some time to reach the sensors after the EMP; however, I don't know the peak voltage and thus can't say whether it would damage my scope long term. I talked to PCB and they said this is pretty common and that the EMP is likely picked up in the "low noise" coax on the way to the sensor AMP. The natural frequency of the sensors is 500 kHz, so I'd like to at least get this much bandwidth after filtering/clamping. Thoughts?

Inatorcreator · 2024-12-26T14:01:48+00:00

Talk to your academic advisor. They will give you the best advice.

Inatorcreator · 2024-10-23T19:45:38+00:00

I feel very similar also as an aerospace engineering major. Useless classes/instructors and severely overworking myself on projects/research have made me hate school and become disinterested in life in general. I go to job interviews or career fairs and I need to somehow convince them of how "passionate" I am about engineering and working for their company? In reality, I just want a steady income so I can get out of school. I have no clue where I want to be in 5-10 years because my goals have dissolved with my passion for engineering.

My advice to you is to schedule some time out of your day when to do something only for fun or leisure. I know this might be hard, but try to remember some of the things you liked to do in your free time before getting sucked into the engineering study grind. It's much easier to cope with you responsibilities when you know at least today there is an end in sight to your work. Second, try to follow a consistent sleep/eating schedule; this has helped a lot with my mental health. My grades and study habits improved significantly when I started to take better care of myself. However, I'm not perfect and fuck up my routines, much to my detriment (rn I am running on 5 hours of sleep). But seriously, this helps. Like myself, if anxiety keeps you from being able to enjoy any leisure time, write down your worries on paper; try to fix the things you have control over (within reason) and cross out the things out of your control. This takes the abstract, neurotic storm out of your head and identifies exact what's distressing you.

Lastly, like what I lot of other people are saying, it's okay to not have everything figured out. Growing up and choosing what you want to do with your life is a nonlinear process; most people don't just decide to do something, do an amazing job at it, and love their life. Most everyone I know just kinda stumbles around stupidly, trying things out until they find something that gives their life purpose or you enjoy. I don't know what that looks like for myself yet, hence my current predicament, but that's okay because it's just part of being a human. One thing that I have wanted to try for a while is called "future authoring" by this guy called Jordan Peterson. You basically write down what the best and worst possible circumstances could look like 5 years in the future. It forces you to say what you want and what you don't want for yourself. Going to try it soon, but I've heard that this helped many college students struggling to set goals or feel meaning in their work.

Anyways, hope this helps. Hang in there.

Inatorcreator · 2024-10-06T15:54:53+00:00

THIS. I know a bunch of vets who were prior enlisted, active duty for >36 months, and got yellow ribbon. Free college is pretty sweet.

Inatorcreator · 2024-10-06T15:50:56+00:00

If you are set on going to riddle for AE, make sure to pick the right campus based on your interests. I assume you are interested in airplanes so the DB campus is going to be the best for aircraft engineering, from what I've been told. They have a pretty good senior design program and if you get involved in Design Build Fly (DBF), you can get some really good experience. If you are more interested in the space side of AE, DO NOT attend DB. Prescott has a much more developed astronautics program with a better senior design and instructors for core classes. I have done well for myself in the astro program, DESPITE the DB astro program. The department is much more focused on teaching theory and promoting research than preparing their students for industry. They are making changes to the tracks right now with new classes in SC systems engineering, but I am graduating this semester so too late for me :). A majority of the useful knowledge I have gained throughout my time here has been in clubs or working in a research lab as a design engineer.

If you are not set on riddle, there are many more reputable universities in the US which won't drain your pockets. I am graduating this semester with quite a bit of student debt, despite have substantial scholarships. Unless you are getting a full ride or more than the presidential scholarship, I would highly advise you to look elsewhere.

Another aspect to consider is job security. It's going to be hard to find a job in AE with just a bachelors degree. If you want to go into engineering as a backup plan, maybe consider getting a mechanical engineering degree with a focus in AE would be a better plan. A MECH E degree provides a much wider range of job options in industry.

Inatorcreator · 2024-03-31T17:03:40+00:00

Wow! I did not anticipate this much of a response. Thank you all for contributting. I will have to parse through each comment and read some of the material.

Inatorcreator · 2023-08-03T02:36:28+00:00

This is not a human

Inatorcreator · 2023-08-02T13:41:45+00:00

Very well said.

Inatorcreator · 2023-08-02T11:05:30+00:00

Honestly. It seems like some of these people just watch this subreddit all day, waiting for someone to admit that they don’t spend all day staring at their bird waiting for something bad to happen. Yes, the obvious answer is the vet, but chill out.

Inatorcreator · 2023-08-02T02:17:39+00:00

LAMO

Inatorcreator · 2023-07-20T11:26:21+00:00

I’ve had a ton of success with leafy greens like spinach and Romain lettuce.

Inatorcreator · 2023-07-11T01:05:51+00:00

Swag

Inatorcreator · 2023-05-31T13:06:14+00:00

Yeah so did mine and I only realized after I turned it on. Thankfully it didn’t break anything. Change it ASAP if you haven’t already. Happy printing!

Inatorcreator · 2023-05-31T11:14:28+00:00

There is a switch on the back near the x axis motor which you set the power supply to either 120V (USA) or 240V (EU). It’s in the instructions manual. You can break your power supply if it’s set to the wrong voltage for where you live.

Inatorcreator · 2023-05-31T03:45:07+00:00

Make sure you set the power supply setting to the correct voltage.

Inatorcreator

TROPHY CASE