Tom Jenkins said:
I never understood why, with our modern technology, they couldn't design a meter that had a single set of plugs for the leads and switched the internal connections when I turned the selector switch on the meter.
I had a Craptsman Meter from Sears that did that. I blew the fuse and the little contacts the first time I tried to measure the amp draw of the blower motor in my '84 Suburban on the 10A range. Later at work, I sprayed it with solvent flux remover (same brand and similar label to the contact cleaner we used...) and welded the plastic together, turning the face to a nice shower-glass-looking glazed blur in the process. As soon as I saw the bubbling, I started trying to take it apart, but it was too late...the knob was now part of the cover. I did manage to separate them later. I still use that POS for DC Volts after popping the cover off the LCD and tossing the case front. Yeah I have done some Pretty pHreakin Dumb schtick myself. I remember using my friend's AC welder with no insulation on the stinger handle, and moving the ground clamp without turning it off. No gloves, stinger in one sweaty hand, ground clamp in the other. Luckily, I was also barefoot, so I was able to throw the dang things down before my chest caved in...this was an emergency boat trailer repair, btw, I usually wear gloves and flip flops while welding...
Tom Jenkins said:
I also never understood why they can't develop a breaker that would act fast enough to protect the meter instead of blowing a fuse.
If there's a breaker faster than semiconductor fuses, put that in my VFD panels, and I'll keep the expensive little fuses in my Fluke.
Tom Jenkins said:
For that matter, I don't understand why they can't design a meter that has a compartment to let me change the fuse without unscrewing the back and taking the whole darned thing apart!
That's to help you remember. If they make it too easy to replace those fuses, you'll end up exposed to danger...I think I like the fact that you have to stop and think about what just happened..pay a little price to deepen the lesson...
The Starr said:
I handed him my Extech EX830 clamp-on.
I know a guy who bought an Extech DC clamp on during his technician training and was using it on a VFD (AC) drive, if I recall correctly. The output under a load, at tech school and the clamp on meter popped in his hand. He said it was like a large firecracker popping in his hand. It didn't break the skin. He showed me the meter, it had a large hole burned through the case where you would grip it! At that time (probably late '90s) that meter was not rated to deal with the PWM of AC drives. I don't recall the model number.
You might want to double check with them, but I did hear that the instructor contacted Ex-Tech and warned them, as well as the company she was training for, and they issued a “Fluke Only” policy...
Okay, back on topic...
I worked with a genius who was having trouble with a 50hp pump controls upgrade. He was supposed to find a replacement for an obsolete contactor. After he installed the replacement and spent three days trying to make it run, I got the tap on the shoulder, “Hey Paul, go see what's wrong with Genius's pump contactor. He changed the motor starter and now it won't pull in...He's been working on it for three days...we need that pump, we need to get it back in rotation so we can catch up on P.M.s”
I opened the box and saw a control transformer about the size of my thumb (480:120) and a contactor with a 120vac coil about the size of a doorknob...
I laughed and said, “Yeah, I can see why it won't seal in. Why did you change the coil to 120v? The print shows 460?”
I put my meter on peak hold and read a low peak of 42vac...
“Yabbit it was the only 460v coil we stock, and I am also tasked with trying to reduce spare parts...”
Yep, that's what I needed added to my plate. A genius EE with no common sense, but motivated to take away my spares and screw up projects...