One of my A/Cs has just failed (Not).

In the Greater Montreal Area (Canada), we have been subject to a prolonged heat-wave, with daily high-temperatures of 35⁰C (+), for approximately a week in a row now. This is expected to continue at least until tomorrow (Thursday, July 5). Luckily, my own home has been protected by two working, 8500BTU air-conditioners until now.

The way an A/C works is such, that it has a compressor-motor, the windings of which are cooled by the return-flow of refrigerant in its gaseous form, after that refrigerant has evaporated in the evaporator, and done its job cooling the home. Yet, these motors are not designed to run with 100% duty, 24/7. They need to cycle off periodically, and one reason for which they normally cycle, is that their function has achieved some sort of (low) target temperature. But, another reason fw the compressor-motor can switch off, is the possibility that its windings themselves, which are linked to yet another temperature-sensor, have overheated.

Even worse than to have the temperature-protection trip once, because of overheated windings, is the very common problem that eventually, the enamel-insulation of the windings may itself fail, causing a permanently defective motor! This tends to happen eventually, because of the cheap way the motors are made.

If that happens, certain turns of the enameled wire, within the motor-windings, will act as if they were the secondary winding of a transformer, to which the still-healthy turns would form the primary winding. A heavy current flows through the short-circuited turns in this way, that can be hard to detect, unless one also measures the exact amount of current drawn by a running motor, and compares it to a known, correct amount of current, which I do not know for the motor in question. But if a winding has in fact started to short in this way, the amount of heat that builds up inside it becomes more acute, of course.

What I am used to from my A/Cs, is that they will run for about 15 minutes, if they fail to reach a target temperature, before their compressors cycle ‘off’. But the A/C in my bedroom, where the temperature is 24⁰C right now, has started to run for only 5 minutes, before turning off. And I have it set to achieve an evaporator-temperature of 20⁰C.

I’ve decided to switch off both my A/Cs temporarily, even though the temperature outside is 35⁰ at the moment, in hopes that they will recuperate. As they are switched off, of course it will start to get warmer in all parts of my home, including in the computer room.

If I should not be able to keep my indoor temperatures under control, I will need to shut down my actual computers next, which are more important to me than the A/Cs, or than my own, personal comfort. In such an event, my blog will also go offline. For the moment, my site and blog are still accessible. But depending on what happens next, there could be some downtime.

(Edit 07/04/2018, 23h05 : )

Apparently, my A/C is still fine. But in order for me to understand this strange behavior, I need to take into account the peculiar way in which my present A/Cs are designed. They are both indoor, portable A/Cs, which have air-ducts that send warm air, with the waste heat, out a window.

Continue reading One of my A/Cs has just failed (Not).

Scheduled Upgrade to my Internet Connection

I follow the somewhat unusual approach, of Hosting my Web-site and this blog, on my PC at home, running as a server. This means that the visibility of the blog is only as good, as the connectivity of this PC (named ‘Phoenix’).

This Friday, June 8, a technician from my ISP will come, to upgrade my Internet connection. Among other things, this upgrade will mean that my Web-server will respond faster, to requests from readers, to fetch blog pages.

But, because of the type of work which the technician will need to do, on Friday itself, I will be temporarily disconnected from the Internet. This also means that at some time on Friday, this blog will not be accessible.

I thank my readers for their patience.

Dirk

 

High Wind-Gusts For now

I host this blog on my home-PC. This means that the blog’s availability is only as good as that of my PC. I do not advise everybody to do it this way; this is just how I do it.

Well right now we are experiencing 80 km/H wind-gusts in Montreal, that are expected to continue throughout the night. Of course, since I also live in a suburb, this could bring about a power-failure. Therefore, within the next few days, this site and blog could go down.

If this happens, I encourage my readers to be patient with me. There would be nothing I could do about it.

Dirk

 

Power Cut Planned.

I take the unusual approach, of Hosting my blog and my site, on my PC at home. What this means, is that the visibility of this blog is only as good as the reliable uptime of the same, home-computer. This is different from what most people would  do, which would be, to go through a professional hosting service.

One benefit of doing it my way, is that I get to tinker and reconfigure my server as I wish, while small-scale hosting arrangements usually require, that the client / author accept the PHP libraries that his hosting service provides, the database which his hosting service provides, etc..

An unfortunate fact which has been brought to my attention, by way of a courtesy letter, is that my power utility will need to replace a batch of power meters, of some minor glitch in the way they do or don’t work. We have power meters that report our consumption wirelessly to the utility, and if there is a malfunction, it’s within their jurisdiction to replace meters.

But, at some point in the next few days, a professional working for the utility will actually have to remove the present meter, and insert a replacement-meter. Which implies that briefly, my power will need to be cut.

This should not take long, and I thank my readers for their patience.

Dirk