atkelar | Grundig RT-3 Restoration @atkelar | Uploaded October 2022 | Updated October 2024, 10 minutes ago.
Some time ago, I had the problem that I needed an insulated 240V supply for a device under test. This led to some ebay searches, and lots of OMG way too expensive results. I built a little cart around a car battery and inverter, so I could at least run anything directly mains supply related from there, and avoid any GFI incidents. My shop does have such devices, so "blowing up my oscilloscope" or getting a fatal shock should not be an issue at all, but better safe than sorry! Also: I do need to poke around in mains parts of power supplies now and then. While the GFI keeps my scope safe, it prevents me from doing exactly that too.
My inverter based solution was working fine; WHEN it was working. That is to say: the charging of a car battery took some time and it ran out almost always whenever I was working on a project. So I did keep on looking for something better, and eventually: I found it!
This device is an RT-3 made by Grundig. RT stands for "Regel-Trenn[trafo]" which is literally meaning "adjustment-separation[transformer]", or as the English wording would be: an isolation variac.
This is by far not the most powerful unit around, nor is it the newest; but it is complete (except a single nut) and works! And no more charging and waiting overnight to continue a project! Woohoo!
Special shout out to @HandToolRescue for the idea to use aluminium tape for label making. Mine is slightly different but I saw the basic concept in one of his videos.
0:00 Intro / Presentation / Disassembly: Case
2:55 Variac Roller / Disassembly: Insides / Schematic
5:03 Variac Damage
5:40 Case Painting
6:42 Switch Cleaning
7:30 Meter / Outlet
8:35 Rebuilding: Variac / Frame / Face Plate
9:55 Soldering: Fuses / Switch / Outlet
10:35 Power On!
11:40 Rubber Feet / Power Switch Mounting / Carry Handle
13:00 Closing the Lid / Changing Rubber Foot
13:52 Knob Cap Replacement / Sticker Remake
15:42 Device Info / Summary / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
Original "Power Bank" video youtube.com/watch?v=pm_uXl3q5bg
Some time ago, I had the problem that I needed an insulated 240V supply for a device under test. This led to some ebay searches, and lots of OMG way too expensive results. I built a little cart around a car battery and inverter, so I could at least run anything directly mains supply related from there, and avoid any GFI incidents. My shop does have such devices, so "blowing up my oscilloscope" or getting a fatal shock should not be an issue at all, but better safe than sorry! Also: I do need to poke around in mains parts of power supplies now and then. While the GFI keeps my scope safe, it prevents me from doing exactly that too.
My inverter based solution was working fine; WHEN it was working. That is to say: the charging of a car battery took some time and it ran out almost always whenever I was working on a project. So I did keep on looking for something better, and eventually: I found it!
This device is an RT-3 made by Grundig. RT stands for "Regel-Trenn[trafo]" which is literally meaning "adjustment-separation[transformer]", or as the English wording would be: an isolation variac.
This is by far not the most powerful unit around, nor is it the newest; but it is complete (except a single nut) and works! And no more charging and waiting overnight to continue a project! Woohoo!
Special shout out to @HandToolRescue for the idea to use aluminium tape for label making. Mine is slightly different but I saw the basic concept in one of his videos.
0:00 Intro / Presentation / Disassembly: Case
2:55 Variac Roller / Disassembly: Insides / Schematic
5:03 Variac Damage
5:40 Case Painting
6:42 Switch Cleaning
7:30 Meter / Outlet
8:35 Rebuilding: Variac / Frame / Face Plate
9:55 Soldering: Fuses / Switch / Outlet
10:35 Power On!
11:40 Rubber Feet / Power Switch Mounting / Carry Handle
13:00 Closing the Lid / Changing Rubber Foot
13:52 Knob Cap Replacement / Sticker Remake
15:42 Device Info / Summary / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
Original "Power Bank" video youtube.com/watch?v=pm_uXl3q5bg
