Very useful devices are the opto-triacs. I used one to directly power a (small) transformer. Works brilliantly. Power is applied when audio is present and has a 5 minute switch off timer when audio finishes.
On the subject of zero crossing switching. Switching a large toroid at the zero point can actually be the worst condition for generating a large inrush current. How large depends on how much residual magnetism is left in the core (which depends on where in the cycle it was switched off). It's better to apply power at the peak of the mains cycle... which goes against initial logic.
I believe once large reservoir caps are added into the equation all that goes out of the window though, and the inrush current is large whatever point in the cycle the transformer is switched. Haven't seen much info on that anywhere.
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Could you give a link to the thread explaining that, after a quick search just now I couldn't turn up any info on it.
Is it only an issue for larger transformers since they will have the most significant inrush condition? I have some smaller transformers (less than 50VA) and smps that I was going to sequence with SSR with zero crossing switching so I am interested to learn more.
Is it only an issue for larger transformers since they will have the most significant inrush condition? I have some smaller transformers (less than 50VA) and smps that I was going to sequence with SSR with zero crossing switching so I am interested to learn more.
Beware of Zero-Crossover Switching of Transformers
http://relays.te.com/appnotes/app_pdfs/13c3206.pdf
http://relays.te.com/appnotes/app_pdfs/13c3206.pdf
It seems that a simple relay is the go. If I was to use a relay. Nice notes on the zero crossover problems, until i read that article i was contemplating using one. I have been reading about triacs they do seem to be a bit noisy unfortunately.
I have been enjoying everyone comments I have been learning quite a bit.
Cheers
I have been enjoying everyone comments I have been learning quite a bit.
Cheers
Hi,
I think the best solution it is the use of a simple and cheapo switch. Making it fancy create more problems. But also here in this link they have an application note page 7 that it is said that the best solution in this case is to fire the traic at the peak or at 90 degree to eliminate the problem. Here it is the link:
http://www.fairchildsemi.com/an/AN/AN-3004.pdf
I think the best solution it is the use of a simple and cheapo switch. Making it fancy create more problems. But also here in this link they have an application note page 7 that it is said that the best solution in this case is to fire the traic at the peak or at 90 degree to eliminate the problem. Here it is the link:
http://www.fairchildsemi.com/an/AN/AN-3004.pdf
Genius!
rotating switch 240v 6A min, any ideas?
I have never used a rotating switch before.
I found Shallco switches they seem heavy gauge, check this Series 16 Rotary Switch, 10 Ampere, Single-Hole Mount on Shallco, Inc.
Is this the sort of thing that will be able to switch Neutral and Active simultaneously?
Cheers
rotating switch 240v 6A min, any ideas?
I have never used a rotating switch before.
I found Shallco switches they seem heavy gauge, check this Series 16 Rotary Switch, 10 Ampere, Single-Hole Mount on Shallco, Inc.
Is this the sort of thing that will be able to switch Neutral and Active simultaneously?
Cheers
Specs read okay. A 2 section one 16A1-b-2 would be required to switch both hot lines you have in Aust. I don't believe you have a neutral in aust., just a safety ground and 2 hots.
This is a US origin switch. You should be able to find a 2 or 3 pole industrial disconnect at an electrical supply. Ask for a "lockout switch". The hole will be harder to machine, but it is not as likely to rotate in the hole as this device could. I have a lot of lockout switches on SS panels in dead motor drives I fished out of the trash at work. The motor drive is plastic trash, but the SS box and switch and heat sink are nice. Nose around a bar near a food plant, you may meet a maintenance man that can scan bins for you.
This is a US origin switch. You should be able to find a 2 or 3 pole industrial disconnect at an electrical supply. Ask for a "lockout switch". The hole will be harder to machine, but it is not as likely to rotate in the hole as this device could. I have a lot of lockout switches on SS panels in dead motor drives I fished out of the trash at work. The motor drive is plastic trash, but the SS box and switch and heat sink are nice. Nose around a bar near a food plant, you may meet a maintenance man that can scan bins for you.
Thanks for the reply indianajo, I have since found a really great switch thats DPNO, see this link if your interested, www.lorlin.co.uk/PDF/RMS.pdf It still present s the problem of becoming loose and rotating but can be tightened with spring washers and maybe nylon blocks either side if it still a problem.
Just as a side note AC in Aus. does have a Neutral, Active and Earth.
cheers
Just as a side note AC in Aus. does have a Neutral, Active and Earth.
cheers
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