Triac for motorized gate controller

[Behemot]

I got this board from motorized gate control unit with the issue of powering motor only in one direction. One of two triacs is blown which seems to be the one and only problem.

There is BTB24-800BW triac, that is 25A, 800V, 50 mA gate treshold. I can get similar triac but also another one with 35mA treshold, for less than 1/5 the price. Since I am not familiar yet with it and can only conclude based on transistors, I can asume lower gate treshold current is not a problem?

[budm]

Re: Triac for motorized gate controller

35ma is just the more sensitive Gate version, so that is find.

[larrymoencurly]

Re: Triac for motorized gate controller

I had a motor control that specified a triac with a 50mA gate, and a 25mA part worked fine but a 3mA part always stayed turned on 100%.

[Behemot]

Re: Triac for motorized gate controller

Oh man, 3 mA, that's less than 1/15th, no wonder it was doing that

[Longbow]

Re: Triac for motorized gate controller

I got this board from motorized gate control unit with the issue of powering motor only in one direction. One of two triacs is blown which seems to be the one and only problem.

Not enough information. What kind of circuit? What kind of motor? Speed controlled, or just on/off? A standard AC induction motor only runs in one direction - is there a gear change box or solenoid to switch directions?

The difference between 35 ma and 50 ma gate is not the issue. That amount of current is the threshold of the average part. You would never design a triac circuit based on the threshold rating. First, I would want to make a good guess at why the one part failed.

[Behemot]

Re: Triac for motorized gate controller

I'd say that each triac is for one direction, that would be consistent with the fact the gate only operates in one way.

I don't have any other informations, I only got the board, not the whole system. It may blow for no apparent reason, that happenes sometimes.

[Longbow]

Re: Triac for motorized gate controller

I'd say that each triac is for one direction, that would be consistent with the fact the gate only operates in one way.

It would be consistent if the gate used 2 motors. A motorized gate would not generally require premium technology components. Simple single phase AC motors only run in one direction.

I don't have any other informations, I only got the board, not the whole system. It may blow for no apparent reason, that happenes sometimes.

It sounds like you were asked to repair the board without knowing what it really does. Yes, failures happen for no reason. I would say in general that parts fail for a specific reason. In this case I'll bet the real problem is still mounted on the gate.

[Behemot]

Re: Triac for motorized gate controller

We'll see after all…BTW, servicing center offered replacement board for quite some money. As nobody asked for anything else, most likely they are aware of this failure which only supports my theory it's nothing more in that.

There is no simple motor but assynchronnous single-phase motor, in that case it's enough to change the phase difference if I am not mistaken so you can just select the right input by opening first or second triac.

[budm]

Re: Triac for motorized gate controller

Can we see the pictures of the board, and any info on the motor (labeling on the motor)?

[Behemot]

Re: Triac for motorized gate controller

Been told there's 1uF cap on the motor, that's all. I am giving the board back today so we'll see by tomorrow if it works or not.

EDIT: enjoy

[Behemot]

Re: Triac for motorized gate controller

I am idiot, I forgot I've been told the serviceman has already tried new working board and the gate operated normally. Customer has reminded that to me again while he was taking the board.

As I have not found any other problem on the board, it again only indicates the triac was the only problem. They have supposedly replaced the motor half a year before this incident so it may have somewhat damaged the triac which ultiamtely blown after some time.

[Behemot]

Re: Triac for motorized gate controller

I have been informed that the gate is running fine.