UK 70TPS12 Thyristor - Help!

[mainline]

Just connected up a dc motor and have the same results as with the LED.

try another thyristor

 

[mangoelectrics]

try another thyristor

No difference!!!

 

[mainline]

No difference!!!

What happens if you put the gate to - and then power the circuit



What do you actually want to do ?

 

[mangoelectrics]

What happens if you put the gate to - and then power the circuit



What do you actually want to do ?

Can you tell me which pin you think is the gate? 1, 2, or 3? From the photo I think it’s pin 3, but thought I would get a second opinion. Thanks!

 

[Moley]

Looking at some data sheets the gate should be the one you've got marked up as 3. Also the minimum gate current to turn on should be 100mA.

 

[mainline]

Can you tell me which pin you think is the gate? 1, 2, or 3? From the photo I think it’s pin 3, but thought I would get a second opinion. Thanks!

 

[mangoelectrics]

Looking at some data sheets the gate should be the one you've got marked up as 3. Also the minimum gate current to turn on should be 100mA.

Thanks both of you. That’s very helpful to know for sure which is which. If I put - to the gate then the led or motor immediately is powered continuously even without the negative lead going into pin 2.

Hope this helps.

 

[mainline]

use a lamp or a motor.

Connect one wire of the motor to - of the battery.
Connect the other side of the motor to the K of the Thyristor.
Connect the A of the thyristor to + of the battery.

Connect a 1k resistor to G of the thyristor and - of the battery.

Power the circuit the motor shouldnt run.

If you run a bit of wire from + of battery and just touch it on to the Gate of the thyristor the motor should run and continue to run.

 

[mangoelectrics]

use a lamp or a motor.

Connect one wire of the motor to - of the battery.
Connect the other side of the motor to the K of the Thyristor.
Connect the A of the thyristor to + of the battery.

Connect a 1k resistor to G of the thyristor and - of the battery.

Power the circuit the motor shouldnt run.

If you run a bit of wire from + of battery and just touch it on to the Gate of the thyristor the motor should run and continue to run.

Will try this in the morning, thanks for your help!

 

[mangoelectrics]

use a lamp or a motor.

Connect one wire of the motor to - of the battery.
Connect the other side of the motor to the K of the Thyristor.
Connect the A of the thyristor to + of the battery.

Connect a 1k resistor to G of the thyristor and - of the battery.

Power the circuit the motor shouldnt run.

If you run a bit of wire from + of battery and just touch it on to the Gate of the thyristor the motor should run and continue to run.

Just tried that now. It does work as you say it should although it takes the positive power in through the gate pin and does not seem to activate the thyristor. Do you know why this might be?

Thanks again!

 

[mangoelectrics]

Also, when I remove the 1k resistor from - to gate then power the gate with + 5v the motor immediately runs, but does not continue to run after I remove the power to the gate, it should continue to run as I have permanent power to the K and A of the thyristor.

Im beginning to think my thyristors are no good?

Thanks!

 

[mangoelectrics]

@Moley Do you have any suggestions?
Thanks!

 

[mainline]

Also, when I remove the 1k resistor from - to gate then power the gate with + 5v the motor immediately runs, but does not continue to run after I remove the power to the gate, it should continue to run as I have permanent power to the K and A of the thyristor.

Im beginning to think my thyristors are no good?

Thanks!

What test gear have you ? I think you should have a read up on how to test scrs.

There are lots of videos on basic electronics etc i think you need to learn a bit more, especially when dealing with mains supplies.


If you just want to switch a higher voltage with a lower one then just use a contactor.

View: https://www.youtube.com/watch?v=dCEt_oaFPMY

 

[mangoelectrics]

What test gear have you ? I think you should have a read up on how to test scrs.

There are lots of videos on basic electronics etc i think you need to learn a bit more, especially when dealing with mains supplies.


If you just want to switch a higher voltage with a lower one then just use a contactor.

View: https://www.youtube.com/watch?v=dCEt_oaFPMY

Thanks, let me explain a bit further.

According to the video, mine are no good. They have measurements of between
G and K: 138 Ω
K and A: 63M Ω and always rising
A and G: 76M Ω and always rising

I am building a coil accelerator and so am needing to use the thyristor to switch on the coil when I give the command. But obviously I am running a 1900uf 450V DC capacitor charged to 400V DC so when I fire it, it gives a HUGE amount of power instantly and this was burning out normal switches.

This is why I was trying to use a thyristor. But if you have another idea of what I could use I would be happy to try that.

Thanks again!

 

[mainline]

Thanks, let me explain a bit further.

According to the video, mine are no good. They have measurements of between
G and K: 138 Ω
K and A: 63M Ω and always rising
A and G: 76M Ω and always rising

I am building a coil accelerator and so am needing to use the thyristor to switch on the coil when I give the command. But obviously I am running a 1900uf 450V DC capacitor charged to 400V DC so when I fire it, it gives a HUGE amount of power instantly and this was burning out normal switches.

This is why I was trying to use a thyristor. But if you have another idea of what I could use I would be happy to try that.

Thanks again!

If you have used those scrs on a coil the back emf may have destroyed them you would need a diode to stop that.