3-phase thyristor control

[roro36]

I want to try and replace the standard relays on our holding pots that are being kept hot by elements. I want to use thyristors instead, but i'm not sure what the best way would be. I would like to implement zero crossing control. So when 1 is fired in the forward dirction, 2 and 3 should be 1/3 into and 1/3 left of their reverse cycles? but ow toactually accomplish this?

 

[Canoeboy]

A little more information is required

What exactly are you trying to do ?

What are you controlling ?

You speak of thyristor control, this will give 0-100% power from a signal (0-10Vdc or 4-20mA for instance) which it gets (normally) from some sort of P, PI, PID controller

Or there are solid state relays (0% crossing firing) which are like electronic contactors, these can also be used for the purpose

SSR's are a lot cheaper than Thyristors

Like i say more info required

Regards

Canoe

 

[roro36]

Its heating elements, that are controlled via a switching rlay, but the contactors are not very good solutions, they wear out too fast. So I want to use zero crossing detection on the line to turn a thyristor on to allow the 50A current through to heat the elements. I a ssr likely to last as long as a thyristor? and give the same control?

 

[Canoeboy]

Use solid state switches, don't buy crap though

I only use siemens, if you choose the right model and protect it with a B type breaker then there is no need for semiconductor fuses either.

Solid state switches will last the same as thyristor controlled.

I'll sort out a siemens part number for you next week when im back in the office if you want

What's the heaters wattage and is it configured star or delta ?