Need help for motor driving with triacs

[mesuthh]

Hello people;
I really need help friends
I am tring to drive a single phase (230V AC) motor 4A with BT137(8A), but triac gets hot like 35 celcius degree (even I am using cooler) and after some switching it is getting failed. So that later on I have changed the triac with BTA41(40A) and heatshink, but it is still hot around 30 degree, and in one week BTA41 also gets failing. I am tring to drve the triac with Moc3041, and I am tring to switching the triac when 5Vdc available on Moc3041.
I have tried to use snubber but it is not solving the problem
you can reach the view of my circuit on  http://img408.imageshack.us/img408/9485/soru1h.jpg

 here I am triying drive the motor with 5V dc control to moc3041 so triac fries and the motor starts, and one more think I am also drving a 25uf 400 V capacitor (paralell with the motor) with that motor for compansating

if someone has an advice I will be really thankfull to him/her
Regards

[Hero999]

TRIACs don't like switching capacitive loads.

You probably also need a snubber network to protect the TRIAC from the back EMF.

[mesuthh]

thank you for your reply sir
I have tried a snuber network as moc3041 datasheet advice but it did not solve my problem.
do you have a specific idea for snubber for this circuit, or is there any calculation for snubbing depending for the load
regards

[cachehiker]

Basic 2 or 4-pole induction motor? Any idea of its resistance or inductance?

I think the snubber is likely where it's at. What values did you use?

You may have to use a larger one to limit 1000W of reactive load to 25 V/

[GelecG]

I have driving 2.2 HP single phase ac induction motor with capacitor like you.
 AND bta41 failing.

snubber and zero crossing is correct.but bta41 in full load suddenly failed.

 can you help me?

[kimico]

The two motor driving rollers of the centrifugal casting machine must keep synchronous and keep load balance。

[hotwaterwizard]

http://www.electro-tech-online.com/electronic-projects-design-ideas-reviews/93323-switching-ac-loads-triac.html

I think the resistor is too small needs to be 330


BT137 Datasheet

http://www.nxp.com/documents/data_sheet/BT137_SERIES.pdf


BTA41

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00002263.pdf

Moc3041 Datasheet

http://www.electro-tech-online.com/custompdfs/2009/05/moc3041.pdf

[ccsintlcircuits]

This one is the great post in which we get information regarding the power driving motor.