triac mot firing with snubber

[ameythatte]

triac not firing due to snubber circuit i am using triac BTA16 800BW driven by MOC3041 for the snubber 220E resistor and0.01 1kv ceramic capactor. between terminals A1 & A2 of the triac. if i remove the snubber the triac works well switching the load.
pl. advice

 

[barry]

Without more information, it's hard to tell. Maybe it's a problem with your drive circuit. Maybe you've got a shorted cap.

 

[ameythatte]

Without more information, it's hard to tell. Maybe it's a problem with your drive circuit. Maybe you've got a shorted cap.

can you pl. explain which capacitor should be used for the snubber. I have used the same circuit as given in MOC 3041 datasheet.
thank you.

 

[barry]

I don't think your chosen values should cause this to not work. (I assume "220E" means 220 ohms and "0.01" means .01uF).

 

[ArNvC]

What kind of load you are using?

 

[ameythatte]

as for now i am testing the circuit with a 20W bulb and am planning to run 1Kw motor using the circuit but when i use the snubber the bulb does not glow on testing with a line tester it shows current even if i remove the MOC3041 .

- - - Updated - - -

pl. explain about the type of capacitor used for the snubber

 

[ArNvC]

Generally you use a snubber circuit for inductive load. Use a snubber while you use the motor load.

 

[jpsganesh]

follow the thread. it may answer ur prob

https://www.edaboard.com/threads/286626/

 

[D.A.(Tony)Stewart]

Consider the triac as a switch with sensitive current gain which latches (self-driven after trigger)

When you load the output with a snubber, you may need a little more drive current.

The MOC3041 is an opto-coupled zero crossing triac to drive power triac with 360R series for 220Vac and 180R for 120Vac.
I suspect your series R is too high so the drive current is too low and when snubber load was applied, it failed. Did you use 180K?

Is it wired correctly to pull up gate with 180R to HOT with 1K GATE to NEUTRAL to reinforce off state of phototriac by shunting leakage.

 

[jpsganesh]

this ckt has snubber for optocoupler too (DIAC side).

after successful run I changed R1, R2 and C1 values still it worked fine.
but R values i tried with less than 1K only.

 

[D.A.(Tony)Stewart]

What load do you have connected when you add snubber?

The triac in your config needs a load to turn on.

Check MOC3021 specs. It is not a DIAC , rather a Opto triac, however for purpose of dv/dt test, it appears like a Diac in D.U.T.

 

[jpsganesh]

What load do you have connected when you add snubber?

The triac in your config needs a load to turn on.

Check MOC3021 specs. It is not a DIAC , rather a Opto triac, however for purpose of dv/dt test, it appears like a Diac in D.U.T.

humm minimum load should be tre.

Optically triggered Triac right?

 

[ameythatte]

i changed the gate to load resistor of 390 ohms with 1K ohms resistor and the triac fired with the snubber. Thanks a lot every one.