Hi All, the specifications for a tlp3063 appear to be conflicting. The peak off state voltage is given as 600v. The minimum isolation voltage is given as 5000vrms.
So is the opto going to be damaged when the voltage at the triac side exceeds 600v or 5000vrms? If it was 5000vrms you wouldn't have to worry about voltage spikes damaging it. I blew a opto when turning on a 240vac motor. The motor was not connected to the opto and triac. It was simply connected to the same L and N line of the mains as the resistive load controlled by the opto.
I will try a 275v mov across the motor terminals to see if this will protect the opto. Tried it already across the terminals without the opto circuit connected. It didn't blow or didn't even get warm.
The motor is rated at .43 amps. I connected it through a fast blow 0.5 amp fuse. The fuse didn't blow. This must be because any damaging high voltage inductive spikes are of too short a duration to blow the fuse but still blow optos. and other semiconductors.
Looking forward to receiving your comments.

 

Hi All, the specifications for a tlp3063 appear to be conflicting. The peak off state voltage is given as 600v. The minimum isolation voltage is given as 5000vrms.
So is the opto going to be damaged when the voltage at the triac side exceeds 600v or 5000vrms? If it was 5000vrms you wouldn't have to worry about voltage spikes damaging it. I blew a opto when turning on a 240vac motor. The motor was not connected to the opto and triac. It was simply connected to the same L and N line of the mains as the resistive load controlled by the opto.
I will try a 275v mov across the motor terminals to see if this will protect the opto. Tried it already across the terminals without the opto circuit connected. It didn't blow or didn't even get warm.
The motor is rated at .43 amps. I connected it through a fast blow 0.5 amp fuse. The fuse didn't blow. This must be because any damaging high voltage inductive spikes are of too short a duration to blow the fuse but still blow optos. and other semiconductors.
Looking forward to receiving your comments.

Isolation voltage is referring to the separation between the two sides of the opto, which in many applications is a serious safety concern. If you've got 240V on one side of the opto, but the other side is a microcontroller with buttons that you touch, it's really important that high voltage never jumps from the high voltage side to the low voltage side and electrocutes you! That's the 5000V rating.

Peak off state voltage is the highest voltage you can have across the TRIAC pins (4 & 6?) without risking damage. That's the 600V number.

So anything over 600V across pins 4&6 might damage the opto, possibly turning the output on or off unexpectedly, but it won't leak any voltage/current over to thev emitter side (pins 1&2) in that scenario, so you shouldn't be electrocuted. Make sense?

 

The MOV sounds like a good idea to me. An RC snubber might also help. The subtleties of these applications are beyond my expertise, but I've had success in the past with RC snubbers in similar situations.

 

Isolation voltage is referring to the separation between the two sides of the opto, which in many applications is a serious safety concern. If you've got 240V on one side of the opto, but the other side is a microcontroller with buttons that you touch, it's really important that high voltage never jumps from the high voltage side to the low voltage side and electrocutes you! That's the 5000V rating.

Peak off state voltage is the highest voltage you can have across the TRIAC pins (4 & 6?) without risking damage. That's the 600V number.

So anything over 600V across pins 4&6 might damage the opto, possibly turning the output on or off unexpectedly, but it won't leak any voltage/current over to thev emitter side (pins 1&2) in that scenario, so you shouldn't be electrocuted. Make sense?

 

thanks ebeowulf17. got it. good answer.
I have a further question on my 275vac mov which gives a clamping voltage of 710v. There is a specification of 13.5 for what is called DIA. Cannot find out anywhere what this means?
Clamping must begin before the 710v otherwise damage would be done to the circuit. The mov probably starts sinking current long before this. A graph of voltage v current shows a fairly steady voltage clamp for increasing current sunk by the mov. At 710v the voltage goes up vertically which would be the 2,500A peak current.
The 13.5 figure may mean amps. It may mean the current being sunk by the mov at the start of the steady voltage clamp?

 

thanks ebeowulf17. got it. good answer.
I have a further question on my 275vac mov which gives a clamping voltage of 710v. There is a specification of 13.5 for what is called DIA. Cannot find out anywhere what this means?
Clamping must begin before the 710v otherwise damage would be done to the circuit. The mov probably starts sinking current long before this. A graph of voltage v current shows a fairly steady voltage clamp for increasing current sunk by the mov. At 710v the voltage goes up vertically which would be the 2,500A peak current.
The 13.5 figure may mean amps. It may mean the current being sunk by the mov at the start of the steady voltage clamp?

Off hand, the only thing that comes to mind is diameter. Otherwise, I'm not sure.

Maybe it would make more sense in context - post a copy of the datasheet here, or at least a link to the part or complete part number.

 

It is diameter although measured in a funny way. It is measured from where the blue part finishes down 1 leg to the opposite side of the mov. The bigger peak current movs have bigger diameters.
Should have guessed that from dia short for diameter.