Products > Test Equipment
Bronson ++ Isolation transformers-Any good?
<< < (7/9) > >>
djsb:
Interesting discussion here about fusing in the live feed only.

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=62064

Can isolation truly ever happen simultaneously in the live and neutral wires? Surely any time overlap is an opportunity for electrocution?
threephase:

--- Quote from: djsb on November 30, 2021, 10:01:34 pm ---Interesting discussion here about fusing in the live feed only.

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=62064

Can isolation truly ever happen simultaneously in the live and neutral wires? Surely any time overlap is an opportunity for electrocution?

--- End quote ---

Ultimately no it can't, but the opportunity for electrocution also exists for the duration that it takes the protective device in the live conductor to break. The extra time taken for a 2-pole device to clear both poles would be negligible. The same argument also applies to 3 phase supplies, technically a 3-pole breaker will not clear all 3 phases simultaneously, but the time differential between them is very low, so in practice it is not a concern, all 3-poles will be cleared within the trip time specification for the circuit.
djsb:
I have removed the PCB in order to investigate the relay contact layout and the additional support circuitry. I have requested a datasheet for the relays (3 off GDYHDZ YH-T90-30-2A and 1 off GDYHDZ YHT72-15-2A) from GDYHDZ in china. I will gradually be building up a schematic layout as I go along. It may take me a while as I have to reverse engineer the board layout. I'm concentrating on the relays first, as they are the business end of the transformer.

The semiconductors so far identified are
1/ Holtek HT46R064B OTP MCU.
2/ JST7805CV regulator.
3/ BD681 power darlington.
4/ 2N5551 high voltage transistors.
5/ 1N5349B Zener diodes.
6/ A few other diodes on the board where I can't see ALL the numbers.
Capacitors.
1/ Electrolytics are all 105 degree XYG make.

The blade terminals on the wires have a locking tab that prevents the blade slipping off the terminal. They won't pull off unless a tab is depressed on the blade. Good to see blades soldered into the PCB.

I will be checking the transformer wiring on Friday to make sure all the windings are actually isolated from each other.
electr_peter:
I am curious of those 4 relays configuration. Likely inrush limiting, but why they have 4?
TheBay:

--- Quote from: electr_peter on December 02, 2021, 01:58:51 pm ---I am curious of those 4 relays configuration. Likely inrush limiting, but why they have 4?

--- End quote ---

To automatically switch between 110/230v Input, the relays will switch the primary transformer taps in series or parallel.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod