UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - HT / filament transformers from Aliexpress

MrBungle · 3rd May 2018, 5:29 pm

Finally some progress.

Firstly specimen A, as sold here: https://www.aliexpress.com/item/Tran...712131800.html

Test equipment:

1. calibrated Keysight U1241C DMM
2. calibrated Fluke 62Max IR thermometer.
3. Loads consisting of a selection of wirewound resistors connected to a choc block

Unloaded voltage on the LV winding is 7.4V RMS

Loaded voltage on the LV winding pulling 600mA (60% rating approx) is 6.3V RMS on the dot.

Unloaded voltage on the HV winding is 162V RMS.

Loaded voltage on the HV winding pulling 17mA (85% rating approx) is 146V RMS

Left for two hours under load, the temperature of the transformer windings measured with the IR thermometer peaked at 41.6 degrees C. Chassis at 38.1 degrees C.

No sign of any problems, degradation or breakdown.

Next one coming up in a few days ...

3rd May 2018, 5:29 pm	#40
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: HT / filament transformers from Aliexpress Finally some progress. Firstly specimen A, as sold here: https://www.aliexpress.com/item/Tran...712131800.html Test equipment: 1. calibrated Keysight U1241C DMM 2. calibrated Fluke 62Max IR thermometer. 3. Loads consisting of a selection of wirewound resistors connected to a choc block Unloaded voltage on the LV winding is 7.4V RMS Loaded voltage on the LV winding pulling 600mA (60% rating approx) is 6.3V RMS on the dot. Unloaded voltage on the HV winding is 162V RMS. Loaded voltage on the HV winding pulling 17mA (85% rating approx) is 146V RMS Left for two hours under load, the temperature of the transformer windings measured with the IR thermometer peaked at 41.6 degrees C. Chassis at 38.1 degrees C. No sign of any problems, degradation or breakdown. Next one coming up in a few days ...