Maker Pro
Maker Pro

Hep please - what resistor size.

punkieys17

Feb 7, 2016
45
Joined
Feb 7, 2016
Messages
45
I am flummoxed. This is a commercial circuit from a pump. It incinerated the resistor and the thyrstor. The thyrsitor is correct but when i connect the pump and energise the reed switch it works once or twice then the thyristor burns out.
The only variable is the resistor size. Its on a 240V AC line. Yhe Igt is stated between 5 & 50MA and the Vgt at 1.2v. Please someone advise to the correct size...and show me the calculation. Any help greatly appreciated. The circuit diagram is complete as in thepump.jpg unit.
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
but when i connect the pump and energise the reed switch it works once or twice then the thyristor burns out.
Is the motor ok? Sounds like it's stalled, seized or otherwise knackered to me.....
 

bertus

Moderator
Nov 8, 2019
3,302
Joined
Nov 8, 2019
Messages
3,302
Hello,

Have a look at the attached application note.

Bertus
 

Attachments

  • AN1007.pdf
    182.6 KB · Views: 4

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
Might also be because you have the device connected wrongly - double check the pinout and your orientation.
 
Top