Skip to main content
DIGIPRESSURE
Associate
May 8, 2024
Solved

The opto coupler fails frequently in the circuit below.

  • May 8, 2024
  • 2 replies
  • 1372 views

hello.
I am using bta16-800-bw for 400v 3 phase motor phase control.
In triac control, the optocoupler frequently fails in the circuit below.
For couplers, use moc3071sm, il4208-x007, etc.
Please see photos for symptoms.

I'm thinking of changing to BTA16-800CW.
I'm asking for advice.

and!
bta16-800-bw Snubless type.
Should I install another snubber circuit like the circuit?
Or is it okay not to use a snubber circuit in the triac?
C14, C15, R8, and R9 you pointed out are snubber circuits, and C is the X-cap.

There were cases where this snubber resistor was damaged or burned.
I would like to ask for advice on two phenomena.

 

출력스위치 정상출력.jpg출력스위치 +측 출력 특성불량현상2.jpg출력스위치 단방향출력 불량현상1.jpgThe picture on the oscilloscope shows line T + fan W of the circuit tested with a differential probe.MOC3071_Circuit.png

This topic has been closed for replies.
Best answer by DIGIPRESSURE

I am using bta16-800-bw for 400v 3 phase motor phase control.
In triac control, the optocoupler frequently fails in the circuit below.
For couplers, use moc3071sm, il4208-x007, etc.
Please see photos for symptoms.

I'm thinking of changing to BTA16-800CW.
I'm asking for advice.

and!
bta16-800-bw Snubless type.
Should I install another snubber circuit like the circuit?
Or is it okay not to use a snubber circuit in the triac?
C14, C15, R8, and R9 you pointed out are snubber circuits, and C is the X-cap.

There were cases where this snubber resistor was damaged or burned.
I would like to ask for advice on two phenomena.

The picture on the oscilloscope shows line T + fan W of the circuit tested with a differential probe.

2 replies

Peter BENSCH
Technical Moderator
May 8, 2024

To get answers from the English-speaking community, it is helpful to ask in English as well. I have therefore translated your text using a web-based tool:

Hello.
I am using a BTA380-3BW for phase control of a 16V 800 phase motor.
The optocoupler fails frequently in the circuit below.
I use MOC3071SM, IL4208-X007, etc.
See the photo for symptoms.

I am thinking of changing to BTA15-800CW.
Looking for advice.

Second!
Is it ok to not use the snubber circuit in a triac without a snubber? The snubber is built into the circuit separately.

There are times when this snubber resistor breaks or burns out.

The photo of the oscilloscope shows line T + fan W in the circuit tested with a differential probe.

I would like to enquire why you are asking in the community of STMicroelectronics if BTA380-3BW, BTA15-800CW and the optotriacs are not devices from STMicroelectronics?

Nevertheless, I'd like to give you a hint: you probably inserted C14 and C15 to realise a capacitive voltage divider, right? Have you taken into account that the capacitors cause a phase shift?

Regards
/Peter

DIGIPRESSURE
Associate
May 9, 2024

hello.
I am using bta16-800-bw for 400v 3 phase motor phase control.
In triac control, the optocoupler frequently fails in the circuit below.
For couplers, use moc3071sm, il4208-x007, etc.
Please see photos for symptoms.

I'm thinking of changing to BTA16-800CW.
I'm asking for advice.

and!
bta16-800-bw Snubless type.
Should I install another snubber circuit like the circuit?
Or is it okay not to use a snubber circuit in the triac?
C14, C15, R8, and R9 you pointed out are snubber circuits, and C is the X-cap.

There were cases where this snubber resistor was damaged or burned.
I would like to ask for advice on two phenomena.

The picture on the oscilloscope shows line T + fan W of the circuit tested with a differential probe.

AScha.3
Super User
May 8, 2024

Hi,

1. write in English.

2. try the standard circuit : from ds ->

AScha3_0-1715161061927.png

R = VPAC / ITSM

 

 

"If you feel a post has answered your question, please click ""Accept as Solution""."