Select the Right Varistors for Overvoltage Circuit Protection | Circuit Breaker Parts

Viking if your cord is getting hot, it’s being overloaded. Time to upgrade the circuit wiring and breaker. The cable doesn’t necessarily have to feel cold, but it shouldn’t feel noticeably warm to the touch either.

Step 3: Use the pulse-rating curves (Fig. 2) in the same datasheet to determine pulse capabilities relative to the 40 pulses at the 1000-A requirement.

I walked in on instrument installation day and began the burn in test of running the halogen fixtures at 100%, then bringing it down over the course of 30 minutes to determine if we had a bad SCR dimmer.

I have plenty of stuff in my garage, including plenty of filled gas cans, but I have nothing within 18″ of the floor. Even the hot-tub boiler is elevated, which is why you see gas water heaters in garages elevated by concrete blocks.

Once upon a time, must have been 13 or 14 at the time, was doing the annual find the blown bulb in the christmas tree lights. Must have completed said mission and marvelled how the bit of cable at the middle/end of the lights was hidden within insulation tape (lights must have been 20 or so years old, this was in the 90s) and the curious being that I am thought let’s see what the tapes hiding – obviously bare wires.

FR4 is actually quite a good insulator. It’s only real failure is when you have impurities on the surface of the PCB in very high humidity conditions. The impurities will cause the surface tension of the water molecules in air to lower and as this happens the water will condense onto the PCB. The water on the PCB reduces the effective creepage clearance and can cause a flash over or arc.

Most people here only deal with low voltages – domestic mains and below. Where I live even mains voltage is lethal.

It happens to the best of us. We power up our project and immediately run into issues. Be it spotty communication or microcontroller reset or any number of bugs that have us mystified and picking though our code… only to find that it’s a power supply issue. Anyone who has tried doing Raspberry Pi stuff and depended on the USB power from their PC has certainly been bit by this.

A 25A relay seems perfect for a 22A load. If the relay is really built for 25A and not only marked as one. What use had a maximum rating when you could never really use it?

many years ago I had the bad behaviour to strip cables using my teeth… well, one day I was ready to strip the end of a cable that used to connected to my portable stereo (240v), its just few seconds that I noticed that the other end was still plugged-in on the mains…

Dust reduction. The Sony A33 has a dust abatement and removal system. A charge-protection coating on the low-pass filter aims to prevent dust adhering in the first place. The sensor shift mechanism used to provide SteadyShot image stabilization also doubles as a shake mechanism to try and free stubborn dust particles that settle on the low-pass filter, although at much lower frequencies than the vibration induced by cameras using a piezoelectric element. From what we can tell, there is no strategy for keeping dust off the translucent mirror, except to blow the surface gently with air; it cannot be cleaned, and should never be touched. A fingerprint would require replacement at a service center.

I know this goes against what many of you have been told and understood your entire career, but take a deep breath and read on.