I am looking for test equipment to perform the Q (resonance) test outlined in MIL-46058C. This test is performed on coupon PCB's with a standard Y pattern an is used to evaluate the performance of coatings applied to the coupon.
Here is a link to the MIL spec I am referencing...
Thanks guys! Great feedback!
The connectors we are using do not have a loop around strain relief so we can't attach a label there.
We are marking each cable end individually with a unige connector reference number to indicate which connector it goes to. The machine has 20 different headers...
I am looking for recommendations for marking ribbon cable assemblies. We need to build and label a bunch of flat, fine pitch (0.025"), 100 circuit cables that are 2.5" wide. The insulation is PVC. I need a label or marker that is moderately durable and will withstand normal installation and...
I really appreciate all the great feedback!
jreaf- Can you send me the manufacturer/model of the non-contact DC voltage sensors you use? I would like to learn more about them.
VE1BLL- Good point on the cap bank tolerance! These big electrolytics are +/-20% Additionally there is one point in...
I want to thank everyone who responded.
VE1BLL- Good suggestion but it would be hard to discharge this bank fast enough to make it safe in the time it would take a user to open the enclosure. The other problem with that approach is the stress put on the caps during a high current discharge and...
All:
I am designing a test system that involves a DUT (device under test) that contains a capacitor bank (5000uF @ 600 VDC). Our test system contains a bleed resistor (7.5k ohm) to discharge the cap bank at the end of the test. I need a safety rated circuit that will detect the voltage of the...
As a follow-up I wanted to let everyone know that the only prohibition I found to wirenuts was in NFPA79 (2007) 13.5.9.2 which states 'Electrical connections at motor terminal boxes shall be made with an identified method of connection. Twist-on wire connectors shall not be used for this...
John,
Thanks for posting that link. I already have a hardcopy of NFPA79 with very dog-eared pages. I have read through the wiring practices section (Ch. 13) but don't see anything about wirenuts.
Thanks again for your reply!
Karl
Karl Edminster
www.electromechanica.com
Does that smell like...
Keith,
I agree that wirenuts seem like a hack but I want to have solid ammo based on something like NFPA79 before I address this with my client. This is the kind of grey area where the judgment of the Authority Having Jurisdiction (AHJ) could cause problems when these units get out in the...
I was reviewing a piece of industrial machinery for a client and discovered the machine builder used wirenuts to connect conductors in several places in the internal wiring of the machine. Included was several places where the protective (earth) ground was spliced/pigtailed using wirenuts. I...
Ed: I looked at the 100S-D contactors you sent but they appear to only be rated for AC operation. The coils are available in AC & DC (perhaps this was the confusion) but the contacts needed to rated for switching DC. This means they need to have magnetic blowouts and/or baffles to quench the arc...
Keith: The resistor crowbar idea is interesting but I would have a hard time verifying it as a category 3 safety system. I would need some sort of fault detection to sense a failed resistor, etc. Using a DP relay is a good idea and I haven't discounted that quite yet...
Ed: Thanks for the AB...
Keith: I considered interrupting the mains but there are large filter caps on the output. Under low/zero load conditions the outputs would remain hazardous for too long after cutting the incomming AC mains hence the need for isolation on the DC side
Roy: Good reminder but fortunately I am very...
Keith: Excellent feedback-thank you!. I agree with your concern about separate contactors not operating simultaneously.
Ed: Thanks for your feedback. I looked at Kilovac but was unable to find an appropriate relay that has auxiliary contacts as required to tie in the safety controller.
I found...
Thank you for your feedback about the ABB part. I should have clarified that although the intent is to never make or break under power it is possible that the relay would need to break under power should the safety system detect an unsafe condition (operator opening the enclosure unexpectedly or...
