Finally, I completed the switch for the Lamptest laboratory, which allowed me to significantly reduce the number of wires on the table and makes the process of testing lamps more convenient.
The task was quite simple - from one common remote control, switch the voltage on the lamp under test (230V-220V-207V-variable), turn on the test lamp lamp through a "switch with backlight" (in fact, through a "neon" from such a switch), control the inclusion of a table lamp and a heating station lamps. In addition, display the current voltage on the test lamp on the indicator of the remote control.
I thought about how to make the switches large enough and convenient, but at the same time compact. I settled on two conventional three-gang built-in switches.
It turned out here is such a design of two blocks connected by a ten-wire MKSH cable (https://ammo1.livejournal.com/1216114.html). On the second block there is a double socket for the tested lamp, a single socket for a table lamp, a triple socket on a long wire - for the lamp warm-up station.
To get three fixed voltages and one variable, I decided to follow the simplest, but cumbersome way - three LATRs and a stabilizer are used. The stabilizer produces exactly 230 V, which are fed to the LATRs - the first, standing on the table, makes a variable voltage, the second and third, standing behind the sphere, give 207V and 220 V. Of course, these two LATRs could be replaced with one transformer, but it would have to be made from something, and the LATRs are ready-made, and they also allow you to fine-tune the voltage.
The switches work only for closing and all three keys have one wire in common, so relays were needed (to make switching and control of different voltage sources). For convenience, I took a ready-made module with six relays (here it is on aliexpress), although, of course, the optocoupler isolation available in it is not needed in this case.
The control unit has a board with a relay, a power source (usual USB charging), a digital voltmeter, a neon light bulb. In the block of sockets only switching.
Did the first test today. It really became more convenient and faster to test the lamps, but a problem was discovered - the heating station control relay "sticks" in the on state. Although 10A is written on Chinese relays, it cannot withstand a couple of dozen low-power LED bulbs (probably they have large starting currents and a spark jumps, due to which the contacts stick together).
I'll try to use a large solid state relay to turn on the "warmers", I hope it will withstand.
It will be necessary to make a similar switch for the house (include table and photo lighting lamps, laboratory power supplies, soldering iron, hair dryer, etc.) to leave only the block with switches on the table, and remove all sockets under table.
© 2022, Alexey Nadezhin
For ten years I have been writing every day about technology, discounts, interesting places and events. Read my blog site ammo1.ru, in Learn, Zen, Mirtesen, Telegram.
My projects:
lamptest.ru. I test LED lamps and help you figure out which ones are good and which are not so good.
Elerus.ru. I collect information about domestic electronic devices for personal use and share it.
You can contact me on Telegram @ammo1 and by mail [email protected].
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